The Liverworts and Hornworts of Colorado

April 28, 2003

THE LIVERWORTS AND HORNWORTS OF COLORADO

W. A. Weber and Ronald C. Wittmann

(A WORK IN PROGRESS)

This portion of the Bryophytes of Colorado is dedicated to

Won Shic Hong

University of Great Falls, Montana

who has contributed mightily to our knowledge of the Colorado Flora

Our Hepatics, usually called liverworts, are small in numbers of species. So many of the genera have only one species, which is wonderful news for amateurs. The larger genera, especially Lophozia, present difficult problems in recognition and dissection. However, with field experience many Lophozia species may be recognized on sight! By far the best source of information with hints on field recognition is Schuster, Boreal Hepaticae (1953). The illustrations are really useful. It is sad that such books are no longer easy to find. We really need a clearing house for good illustrations of hepatics!

*** introductory morphological material, terminology (spores, elaters, pseudoperianth, etc.)

THE THALLOID LIVERWORTS

A note about the families: In a local flora, especially one in which the number of genera and species is very low, as here in the Rocky Mountains, it makes little sense to try to think of families. Learning the liverworts begins with recognizing a species, then a few more, getting the feel for a genus. This is often as far as the non-specialist wants or needs to go. Too many families are controversial. Genera are less so. So pardon us if we slight the family characteristics.

Microscopic characters: For field botanists it will be impossible to follow some generic keys that deal with cell sizes and other microscopic characters. Until you have the necessary experience with the genus that you feel you need to do microscopic work, you may have to be satisfied with recognizing the genus.

ANEURACEAE

1a. Thallus large, unbranched or nearly so; thallus thick, bright green and greasy in appearance, 10-15 cells thick and 4-10 mm wide; oil bodies absent; calyptra hairy. Aneura

1b. Thallus small and rather delicate, thin, dull, 4-9 cells thick, less than 2 mm wide, regularly pinnately branched, the ultimate branches thin-edged about 2-3 cells wide and 1 cell thick. Riccardia

Aneura

Aneura pinguis, our only species, consists of a very simple, usually unbranched thallus up to 6 mm wide, opaque green, rather rigid and thickish, with a greasy appearance. There is no mid-rib. It is closest in appearance to Pellia, but that is thinner and has a mid-rib. Female plants have erect, club-shaped green calyptras. The fragile seta and black, oblong capsule stick up through the top of the calyptra.

Aneura pinguis (L.) Dum. We have one record: Chaffee Co.: Wet ground, St. Elmo, 10,000 ft., Kiener 6695 (with fruit!) (Riccardia pinguis (L.) S. F. Gray, Trichostylium pinguis Schuster, Bryologist 61:53. 1958).

Riccardia

Riccardia multifida (L.) S.Gray. We have only one record, Larimer Co.: On soil, Chiquita Creek, Rocky Mountain National Park, Hong 78-921 (Hong 1980). We have no specimens in the COLO herbarium.

ANTHELIACEAE

Anthelia

Anthelia is an exceedingly common plant of melting snow-beds in the alpine tundra. However, it is rarely recognized as a plant because it forms black, more or less amorphous patches. It is only upon very close examination that it is seen to consist of minute stems. In the field Anthelia usually has a grayish color because of a covering of either fungal hyphae or terpenoid chemical compounds.

Anthelia juratzkana (Limpr.) Trevis. There are two species of Anthelia. The second one, A. julacea, occurs in areas with a more oceanic climate than Colorado. Fortunately we do not need to distinguish them here, since technically they differ in spore size (A. julacea having spores 14-15 microns, A. juratzkana 17-20 microns). I have not seen Anthelia fruiting here. We have specimens from Boulder, Grand, Larimer, Park, Pitkin, and San Juan counties. It can be found in most snow-melt basins.

ANTHOCEROTACEAE

The hornworts, as these are called, form a separate class from other liverworts: The Anthocerotae. They are different in all respects from other hepatics. The sporophyte, rather than having an ephemeral seta, is green and persists until the death if the thallus.. The capsule is long and cylindric instead of round or oval. The capsule is two-valved rather than four. The cells of the thallus are thin-walled, never with corner thickenings (trigones), and they have a single, large saucer-like chloroplast.

1a. Sporophytes small, nearly horizontal, surrounded until maturity by the perichaetia. Carpobrotus

1b. Sporophytes tall, erect, cylindrical, projecting far beyond the perichaetia at maturity. Phaeoceros

Carpobrotus

C. orbicularis Schwein. Our only collection is from Alamosa Co.: East edge of Alamosa, on alluvial deposit, bank of Rio Grande River; very scattered, with Riccia frostii, McGregor 7465. There has not been an attempt to rediscover this, and the town of Alamosa probably has grown to encompass and destroy the locality. The species forms small rosettes similar to those of Riccia, but the thallus is clear green and not appressed to the ground.

Phaeoceros

P. laevis (L.) Prosk. Our only collection is from Boulder Co.: Boulder [presumably on the White Rocks], 1908, Bethel. If it still persists, it should be sought on moist underhangs of the Fox Hills Formation at the White Rocks Preserve, 8 mi NE of Boulder. In Phaeoceros the spores are yellow. In Anthoceros, for which we have no reports, the spores are black.

May 8, 2003 AYTONIACEAE

In this family, a critical character is the structure of the pores that open into the air-spaces of the thallus. Making thin sections showing the surface view or the cross-section of these is not an easy task, but it is worth while to explain what the architecture of the surrounding tissue is like. Many times the determination of the genus depends on our knowledge of the pores. Also, sporophytes are usually necessary for identification. Count yourself very lucky to find specimens with well-developed female receptacles. These are beautiful structures and vital in distinguishing the genera. Treat them gently so that hey are not damaged by pressing.

1a. Plants with female receptacles.............................................................................................. (2)

1b. Plants lacking female receptacles......................................................................................... (4)

2a. Female receptacles (carpocephala) with a white pseudoperianth surrounding the capsule; stalk lacking scales at the base......................................................................................................................... Asterella

2b. Female receptacles lacking a pseudoperianth....................................................................... (3)

3a. Stalk very short (3 mm or less),arising from the thallus surface, lacking a rhizoid furrow; the receptacle cap smooth; involucre 2-lipped (lengthwise). Plagiochasma

3b. Stalk elongate, arising from the thallus notch, with a rhizoid furrow; receptacle cap with low coarse tubercles, not lipped. Mannia

4a. Thallus pores bounded by 4-6 cells, not in several radial rows. Plagiochasma

4b. Thallus pores bounded by several radial rows of cells........................................................... (5)

5a. Subalpine species. Asterella

5b. Foothills species. Mannia

Asterella

Asterella is a thalloid liverwort with a bluish-green color. It is easily recognized when fruiting because it produces a stalked umbrella that is simply hemispherical, not lobed, and under the umbrella four sessile sporophytes that are enveloped by a hyaline pseudoperianth. This splits into a fringe of linear white segments or remains attached at the end, forming a “Chinese lantern” cage. In Mannia fragrans there are white scales, but these are on the upper end of the stalk, not around the sporophytes. The thallus surface has small hexagonal markings (these lines indicate the places where the air chambers are separated). The ventral scales are small and do not protrude as a tuft at the thallus tip as in the similar Mannia fragrans.

1a. Thallus about 2 mm wide. A. gracilis

1b. Thallus 4-6 mm wide. A. lindenbergiana

A. gracilis (F. Web.) Underw. is our only species. Evans (1915) reported it from Boulder, Bethel 4; Gilpin Co.: near Tolland, Young. We have specimens from Gunnison, Larimer, and San Juan counties. All of our specimens are from the subalpine, 10,000-12,000 ft.

A. lindenbergiana (Corda) Lindenb. Infrequent or rare, wet subalpine spruce forests. Por specimens from Summit Co.: mouth of Monte Cristo Creek, 2 mi N of Hoosier Pass, 11,000 ft., Weber & Holmen B-4428, !M. Hicks; Boulder Co.: trail from 4^th of July Canyon to Arapahos Glacier, 10-11,000 ft., Shushan B-15728.

Mannia

1a. Stalk of sporophyte with very slender, white “bracts” along its length. M. pilosa

1b. Stalk of sporophyte naked................................................................................................... (2)

2a. Thallus 2-4 mm wide, 1.5-2.0 cm long; appendages of ventral scales very large, 2-3 in number, hyaline and forming a conspicuous cluster at the thallus apex; epidermis firm, not becoming lacunose; plants strongly aromatic. M. fragrans

2b. Thallus 1.5-3,0 mm wide, 0.8-1.5 cm long; fertile plants with appendages of ventral scales 1-2, not forming a “beard” at apex of thallus; epidermis fragile, becoming lacunose in age; plants without odor. M. rupestris

M. fragrans (Balb.) Frye & Clark. Evans (1915) reports this from Grand and Larimer counties. Our specimens are from Boulder, Gunnison, La Plata, Larimer, and Montezuma counties.

M. pilosa (Hornem.) Frye & Clark. Known from two collections: Baca Co.: Rin rock, Big Hole Canyon, Carrizo Creek drainage, Weber & Wittmann B-100956; Teller Co.: Twin Trocms Valey, Florissant Fossil Beds, 12 Aug. 1985, Edwards et al. B-89815.

M. rupestris (Nees) Frye & Clark. Our collections are from Boulder Co.: 4 mi NW of Lyons, 6,500 ft. alt; on north-facing ledges, Weber B-27931; Larimer Co.: Moss-covered ledges of N-facing wall of Little Thompson Canyon 10 mi NW of Lyons, 7,500 ft. alt., Weber B-6092.

Plagiochasma

Plagiochasma is a southern genus, appearing in only the southernmost counties, on protected ledges of sandstone rim rock. Unlike Mannia, which grows mostly as solitary thalli, Plagiochasma forms large colonies. The species are very easy to distinguish when they are fresh. Plagiochasma shares with Athalamia (Cleveaceae) the character of the sporangiophore being produced on the surface of the thallus, in this instance with a fringe of white scales surrounding its base. The thallus rolls up to show a purple underside.

1a. Thallus green; epidermal hexagons inconspicuous, not easily made out with the hand lens; pores usually surrounded by six radial rows of 2-3 cells. P. wrightii

1b Thallus glaucous, blue-green; epidermal hexagons easily visible with a hand lens; pores usually surrounded by one circle of 4-6 cells with no further radiate layers. P. rupestre

BLASIACEAE

We have the single genus, Blasia. This is a rather small, thin, green thalloid liverwort with distinctly crenate and ruffled margins. Scattered over the thallus are dark purplish, swollen spots which are actually symbiotic colonies of Nostoc living in the Blasia thallus. The plants commonly form rosettes. The branches have a more or less distinct mid-vein. The most outstanding feature is the production of gemmae in flask-shaped organs on the upper distal surface of the thallus. The flasks point forward in the direction of growth and are abruptly narrowed to an elongate neck through which the oval gemmae are discharged a few at a time. Blasia may also produce star-shaped gemmae directly on the thallus surface.

Blasia

B. pusilla (L.) Micheli. Blasia occurs typically on raised grassy hummocks in wet grasslands. Our only collection to date is the following: Larimer Co.: heavy soil on knoll in swale at base of bluff near Little South Cache La Poudre River, ca. 9,000 ft., 28 mi. W of Fort Collins, 11 Aug. 1961, Hermann 16,980 (COLO B-9120).

CLEVEACEAE

We have the single monotypic genus, Athalamia. The thallus has hyaline or pale violet scales with very large cells, tapering appendages protruding beyond the thallus margins (see also Mannia fragrans); thallus color is pale crystalline green, margins not very purplish; carpo-cephala are dorsal on the thallus (as in Plagiochasma), not from an apical notch; pit-like depressions fringed with white scales mark where the carpocephala will arise; pores have thickened radial (stellate) cell walls.

Athalamia

Athalamia hyalina (Somm.) Hatt. A common thalloid liverwort of the alpine and subalpine. We have collections from Boulder, Gunnison, Huerfano, Larimer, Park, and Saguache counties. See Preissia for discussion of differences.

CONOCEPHALACEAE

Our only genus, Conocephalum, is the giant among Colorado liverworts. It is larger than Marchantia, more yellow-green in color, more flabby than stiff, and has very coarse polygonal areoles, each with an obvious white pore. It is said to have a fragrant odor (I find it more peppery). There are no gemma cups. The carpocephala are rarely produced in Colorado, but when present the stalked ones are only female and conical (whence the name Conocephalum!) (antheridial receptacles are sessile on the thallus surface.

Conocephalum

C. conicum (L.) Dum. A very common species along small streams in the foothills and montane zones.

MARCHANTIACEAE

Key to the Genera

1a. Ventral scales deep purplish, in two rows; gemmae absent; female receptacles shallowly 4-5-lobed on the margins, or hardly lobed; ventral scales without oil cells (or at most with only one or two). Preissia

1b. Ventral scales colorless or pinkish, in 4 to 6 rows; gemmae in distinct, cup-like receptacles, female receptacles very deeply divided into 5-9 lobes or segments; ventral scales with oil cells. Marchantia

Marchantia

1a. Common plants from the plains to the montane. M. polymorpha

1b. Restricted to the subalpine and alpine. M. alpestris

M. alpestris Nees. Very common on the edges of streamlets and rills in the subalpine and alpine. See table below for distinctions between this and the next.

M. polymorpha L. Very common along streamsides from the plains to the montane. Replaced at higher altitudes by M. alpestris.

Table of characters, Marchantia alpestris vs. polymorpha, based on Warncke (1968)

Thallus:

(M.a.): Broad, thick, leathery; (M. p.) smaller, thinner, and linear

(M.a.): Short-branched, branches very often equally developed; (M.p.) Long branched, one branch “suppressing the other”

(M.a.): Middle line never developed; (M.p.) Middle line always present in adult thalli, Depressed and more or less dark (to grooved and black in var. aquatica)

(M.a.): Middle path distinct; (M.p.) Middle path seldom developed

(M.a.):Bluish green, waxy; margins of older thallus rust-red; (M.p.) Gray-green to yellowish (in var. aquatica)

(M.a.): Gemma cups not rare; (M.p.) Gemmae cups nearly always present (very rare in var. aquatica)

(M.a.): Prostrate in dense, compact patches (M.p.) Prostrate (to suberect in tufts in var. aquatica)

Archegoniophore:

(M.a.): stalk short, stout, square; (M. p.) Stalk longer, slender, rounded

Rays oval to flat, strong; (M.p.) Rays longer, slender, rounded

Perichaetium very well developed, covering more than half of the rays; (M.p.):

Perichaetium only slightly developed, covering a third of the rays.

Preissia

One species, P. quadrata (Scop.) Nees. Frequent on packed moist soil, especially along seeping cliffs. Much smaller than Marchantia, not forming an elongated and branched thallus. If one has difficulty in distinguishing between these fairly similar genera, no one has given us better advice than Schuster (1953):

“The moderate size (usually between 6-10 mm wide and 2-4 cm long), and the dull green color, with the lateral thallus margins somewhat purplish, and the ventral scales always blackish-purple, give the species a rather characteristic appearance, even when sterile. Confusion is possible only with Reboulia and Athalamia (which are similar in size), while the smaller size (of Mannia) at once eliminates that genus. From all of these genera, and all other genera except Marchantia, Preissia differs at once in its elevated, whitish, rather prominent compound [barrel-shaped] pores. In Reboulia the pores are simple (that is, flanked by a single layer of cells), and the epidermal cells are distinctly collenchymatous (in Preissia always very thin-walled and lacking trigones). In Athalamia the pores are stellate and simple, and very different from those of Preissia. Reboulia, with which Preissia frequently occurs, can usually be separated from Preissia in the field by the smooth and often slightly more yellow-green thallus, with the pores extremely inconspicuous, while the thalli of Preissia are a little rough because of the many elevated, whitish pores, and usually of a duller green color. The margins of the thalli of Preissia are also usually bleached and decolorate—never in Reboulia.”

METZGERIACEAE

This family is characterized by its thin, ribbon-like thallus one cell thick and only a few millimeters wide, with a distinct midrib of several cell layers; the thallus margin has marginal hairs. Our single genus, Apometzgeria, is sometimes included in Metzgeria proper, is characterized by having a dense cover of hairs above and below.

Apometzgeria

A. pubescens (Schrank) Kuw. This is a flat, branched, one-cell thick thallus with a thickened midrib. In contrast with Aneura pinguis, it is very thin and delicate and grows on relatively dry forest floors with other liverworts. We only have one member of the family in Colorado, and this is instantly distinguishable from the genus Metzgeria, one or two of which might be expected here, because the thallus is densely pilose on the surface. The species is characteristic of mature, well-vegetated forest floors in the subalpine zone.

REBOULIACEAE

Reboulia

The salient features of Reboulia are: Larger than Mannia or Asterella (about the size of Preissia); relatively smooth and yellow-green upper surface with inconspicuous pores (Preissia is rough, bluish-green, with elevated pores; the older thallus portions never become bleached or white (Preissia does); the carpocephala are moderately 5-7-lobed; the pores are surrounded by 4-5 concentric rings of cells; the epidermal cells have distinct trigones; the stalk of the carpo-cephalum has a cluster of very narrow filamentous scales (in Mannia these are lanceolate-linear).

R. hemispherica (L.) Raddi. Evans (1915) reports a Brandegee specimen, and from Grand Co.: Granby, Bethel 3. We have no recent collections.

RICCIACEAE

1a. Plants forming neat rosettes not more than 1 cm diameter; on ground. Riccia

1b. Plants submerged or floating. Ricciocarpus

Riccia

1a. Thallus with photosynthetic, internal tissue loose, forming large air-chambers (in cross section the thallus is not compact in structure; surface of terrestrial forms often lacunose and spongy with age; mostly aquatic or mud-inhabiting species of the plains.............................................................................................. (2)

1b. Thallus with compact photosynthetic tissue; mostly mountain or desert-steppe ...................... (4)

2a. Thallus with the segments narrowly linear, mostly less than 0.7 mm wide; occurring free-floating under the water surface, or stranded. R. fluitans

2b. Thalli with segments relatively broad, usually over 0.7 mm wide, always terrestrial................. (3)

3a. Thallus glaucous; dorsal epidermis becoming spongy. R. frostii

3b. Thallus bright green; dorsal epidermis actually degenerating and disappearing. R. cavernosa

4a. Thallus with either white ventral scales or marginal cilia......................................................... (5)

4b. Thallus lacking white scales or marginal cilia. R. sorocarpa

5a. Thallus with conspicuous white ventral scales visible on margins of dried thalli; desert-steppe species. R. austinii

5b. Thallus margins with distinct cilia, stout, usually numerous, 75-300 microns long. R. beyrichiana

R. austinii Steph. A desert-steppe species occurring on sandstone-derived soils on the Western Slope. It is easily recognized because of the conspicuous white ventral scales that become visible when the thallus dries and curls up. Our single collection is from Moffat Co.: North base of Douglas Mountain 6 mi W of Greystone, 2,300 m; in soil accumulating in depressions at the base of shelving sandstone rim rock, 27 Aug. 1975, Weber B-49823.

R. beyrichiana Hampe. We have a single specimen: Jackson Co.: morainal pond between Jack Creek ranch and Teller City, 12 mi E of Rand, in muck at edge of pond, 9,300 ft., Douglass 61-580. Evans (1915) cited a specimen from Lake Eldora, Boulder Co., as R. lescuriana Austin.

R. cavernosa Hoffm. emend. Raddi. A fairly common species on very wet streambanks and pond borders, low and middle altitudes. Evans (1915) reports this as R. crystallina. We have collections from Boulder , El Paso, and Grand Counties (R. crystallina of authors, not L.).

R. fluitans L. This is a low altitude species. We have one verified collection, from the eastern plains: Morgan Co.: with Ricciocarpus natans in small side stream out of the main current, South Platte River 8 mi W of Fort Morgan, Mattoon 7978. It is probably frequent and widespread in the irrigated areas of eastern Colorado.

R. frostii Aust. We have collections from Boulder, Jefferson, Gunnison, Mesa, and Moffat counties. A representative collection is Boulder Co.: Bed of pond at Nine mile Corner 9 mi E of Boulder, Weber & Shushan 7980. This pond has filled with cat-tails and no longer supports any liverworts; and Jefferson Co.: just W of Church’s lake, on drying mud flat around small pond 1 mi S of Broomfield, 5,500 ft., Weber 8659. No liverworts have been found in recent years in the ponds of the Colorado Piedmont. Their margins have been dredged to prevent the formation of mud flats, and the margins of the larger lakes like Boulder Reservoir have been heavily polluted by Canada Goose droppings and do not support any vegetation.

R. sorocarpa Bisch. A common species in protected places on well-vegetated tundra slopes, generally on the sides and bases of overhanging tussocks of Kobresia. We have collections from Boulder, Clear Creek, Moffat, Park, and Pitkin counties.

LEAFY LIVERWORTS

BLEPHAROSTOMACEAE

The family is monotypic. It is distinguished by the leaves, which are normally four-lobed to the base, with each lobe one cell wide; the underleaves are similarly three-lobed. Technical differences in the sporophyte serve to separate it from superficially similar families.

Blepharostoma

We have a single species, B. trichophyllum (L.) Dum. Trichophylla is an apt epithet, because the leaves are divided into four one-cell thick “fingers”. The slender, yellowish-green plants are very small, delicate, and easily overlooked among other liverwort clumps, but sometimes they occur in large, pure stands, as we found them under dwarf birches at Blue Lake. The underleaves are similar bot only trifid. There are other liverworts with leaves that are variously dissected, but In Colorado there is nothing like Blepharostoma. It is generally restricted to the subalpine zone and lower alpine ecotone, where it is very common.

CALYPOGEIACEAE

Ref.: Hong (1990)

Calypogeia

Calypogeia, our only genus, is characterized by having entire. Simple leaves that are distinctly incubously inserted. The underleaves are large and either bilobed or virtually entire. At their base is a distinct cushioned area formed of smaller cells, the rhizoid-initial region. There is no perianth, but a fleshy, subterranean hairy perigynium arises from a very short branchlet coming from the axil of an underleaf. The plants are pale, rather transparent, bluish-green in color.

1a. Underleaves deeply divided (over half of their length) into two lobes..................................... (2)

1b. Underleaves undivided, or shallowly (less than 1/4 of their length, into two lobes................... (4)

2a. Leaf cells small (less than 30 microns in the apex, 25-35 x 30-45 microns in middle); underleaves more than 2x (3.2-3.5) wider than the stem. C. suecica

2b. Leaf cells large (over 30 microns in apex, 35-50 x 45-70 microns in middle); underleaves less than 2x (1-2) wider than the stem....................................................................................................................... (4)

3a. Leaves bidentate or sharply pointed at apex; underleaves ca. 1.5-2x wider than long, 1.5-2x wider than stem. C. fissa

3b. Leaves entire or narrowly rounded at apex; underleaves 1-1.5x wider than long, 2-2.5x wider than stem. C. muelleriana

4a. Leaf cells 35-45 x 40-60 microns in mid-leaf; underleaves broadly orbicular, ca 1.2-1.5 x as wide as long, 2-3x wider than stem; rhizoid initial area distinct; border of elongate cells indistinct. C. integristipula

4b. Leaf cells 30-40 x 35-45 microns in mid-leaf; underleaves orbicular, almost as long as wide, 2-2.5x wider than stem; rhizoidal initial area indistinct; border of elongate cells very distinct. C. neesiana

C. fissa (L.) Raddi. It is really questionable whether this occurs in Colorado. Hong’s map shows the distribution as being confined to the Pacific coast states. Hong did not cite any specimens, nor does he show the position of any Colorado stations on his map, p. 315. Nevertheless he states its range as including Colorado.

C. integristipula Steph. Hong cites collections from Boulder, Grand, Gunnison, and Larimer counties.

Leaves incubous, not lobed; obtuse, a little less wide than long; leaf border not apparent; leaf cells lacking trigones, 40-50 µ; oil bodies oblong, 3-4 per cell, lumpy, not colored; underleaves 2-3-times wider than stem, wider than long, very shallowly lobed. the rhizoidal initial layer with debris clinging to it, hence very distinct (B-112439).

CEPHALOZIACEAE

Ref.: Hong (1988)

Cephalozia is our only genus. In this genus the plants are very tiny, creeping or prostrate. The stems have large, pellucid, thin-walled cortical cells. The leaves are obliquely inserted, bilobed, with the lobes often pointing toward each other, without cell wall thickening. There are no underleaves. The plants occur on peat, humus, or decaying logs. They are usually somewhat larger than Cephaloziella, which has almost transversely inserted leaves.

Cephalozia

1a. Leaves slightly decurrent, orbicular, horizontally or obliquely inserted, bilobed 0.2-0.5 their length, the lobes somewhat connivent. C. pleniceps

1b. Leaves never distinctly decurrent, ovate (longer than wide, 1.1-1.4 times as long as broad), almost transversely inserted, bilobed for 0.5-07 their length; lobes never connivent............................................. (2)

2a. Leaves bilobed for 0.5-0.6 of their length, cells 30-40 x 40-50 microns in leaf base, with thin, non-pigmented walls; mouth of perianth denticulate (with minute teeth); gemmae rare. C. bicuspidata

2b. Leaves bilobed for 0.4-0.5 their length, cells 20-25 x 20-35 microns in leaf base, with thick brownish-golden walls; mouth of perianth crenulate (with rounded teeth); gemmae frequent. C. ambigua

C. ambigua Mass.. Hong cited a single collection: Boulder Co.: North Fork [of Boulder Creek?], Hong 78-953; Jackson Co.: Michigan River, Hong 78-807; Larimer Co.: Sheep Creek, Hong 67-783.

C. bicuspidata (L.) Dum. Representative collections: Boulder Co.: spruce-fir woods below Ouzel Falls, Rocky Mountain National Park, 9,400 ft. alt., Hermann 27787 (who called it C. pleniceps); Gunnison Co.: Iron fen. Mt. Emmons, 9600 ft., Weber B-92630 !Hong.

C. pleniceps (Aust.) Lindb. Hong (1980) cites one collection: Larimer Co.: Rocky Mountain National Park; Roaring River, Hong 78-885.

CEPHALOZIELLACEAE

Ref.: Hong (2986)

Cephaloziella

These are the smallest known liverworts. If you thought Cephalozia was small! The plants are only 1-8 mm long, filiform, with the leaves only a little wider than the stems. The leaves are distant and transversely inserted, bilobed for ½-3/4 their length, with the lobes only 2-9 cells broad at base. The leaf cells never have trigones. Our species are found on moist rotten wood and among mosses in high subalpine or alpine situations. They are usually discovered while one is dissecting a larger bryophyte.

1a. Leaves often dentate; underleaves present and distinct. C. divaricata

1b. Leaves edentate; underleaves absent or minute if present...................................................... (2)

2a. Leaf lobes oval-lanceolate, 3-8 cells wide at base; cells strongly thick-walled; plants red-brown. C. rubella

2b. Leaf lobes ovate-triangular, 5-15 cells wide at the base; cells thin-walled.............................. (3)

3a. Plants purple-black; leaves erect or suberect; leaf lobes blunt or rounded, 6-12 cells wide at base; gemmae absent; calciphile. C. arctica

3b. Plants green-brown; leaves distantly strongly spreading; leaf lobes acute, 5-8 cells wide at base; gemmae pale green; non-calciphile. C. hampeana

C. arctica Bryhn & Douin. A distinctive black species of the upper subalpine or alpine. Hong cited a specimen from Larimer Co.: Rocky Mountain park, Trail Ridge, Hultén s.n. (S). We have excellent new collections from Summit Co.: Blue Lake, on seeping limestone ledges, 11,000 ft. alt., where it occurs with the equally black Didymodon subandreaeoides. Weber & Wittmann 111181(!Hong).

C. divaricata (J. E. Sm.) Schiffn. A fairly common green species from the foothills to alpine. Boulder Co.: Boulder Canyon, Weber B-10554 is representative.

C. hampeana (Nees) Schiffn. Especially common on burned stumps. Hong cited specimens from Boulder, El Paso, and Larimer counties. A fine representative collection is Boulder Co.: Rocky Mountain Nat. Park, Bear Lake tourist trail; forming a continuous carpet on soggy ground of inlet area, Weber & Wittmann B-111256.

C. rubella (Nees) Warnst. Easily recognized by its reddish brown color, this species seems to be common in the foothill canyons on north-facing cliffs.

FRULLANIACEAE

Our members of the family have complicate-bilobed leaves, one lobe dorsal, the other ventral, but quite different from that of Scapania. The dorsal lobe is typically round, and the insertion incubous. A curious ventral lobe is seen underneath, which is smaller and most often three-dimensional, helmet-shaped like an upside-down cup, connected by a small stalk to the upper lobe. In some species the cup is only imperfectly cup-shaped and not closed along the side (explanate). The stem also has underleaves, in our species always bifid. All of the species are pioneer types rarely mixed with other mosses except where they occur as thin colonies on cliffs. In Colorado all of our species tend to be cliff-dwellers, while in more humid climates they are most common on tree-trunks.

Frullania

Ref.: Hong (1989)

1a. Ventral lobes very small (less than half the size of the dorsal lobes), strongly explanate (evidently with no helmet-shaped lobules), lanceolate; perianth with five keels; underleaves bifid to a third their length. F. inflata

1b. Ventral lobes strongly inflated (helmet-shaped), rarely weakly explanate, especially near the stem apex; perianth with 3-9 keels.............................................................................................................................. 2)

2a. Ventral lobes mixed, helmet shaped on more mature stems, explanate on the younger ones; underleaves large (3/4 as wide as the stem), wider than long. F. riparia

2b. Ventral lobes inflated uniformly, never explanate; underleaves large (3-4 times as wide as the stem. F. brittoniae

F. brittoniae Evans. Frequent in seepage zones on vertical cliffs. We have collections from Boulder, Clear Creek, Grand, Hinsdale, Montrose, and Rio Grande counties.

F. inflata Gott. This species is usually found on bark. It has not yet been found in Colorado, but should be expected in the southern counties, since it comes as far north as Las Vegas, New Mexico. There may be small pockets of canyons where the humidity is high enough to support the species.

F. riparia Hampe. Our only collection is from Las Animas Co.: Carrizo Creek, Shush an B-6903.

GEOCALYCACEAE

Ref.: Hong (1993), Engel & Schuster (1984). Engel & Schuster (1984) reduced Lophocolea to synonymy under Chiloscyphus, but Hong rejects this merger because of differences in the perianth, male inflorescence, leaves, underleaves, and bracts. We feel that it is justifiable for us to follow Hong in the long-standing treatment.

This family contains genera that are not obviously alike. The leaves are succubous or obliquely inserted; the underleaves are bilobed; rhizoids are restricted to the bases of the underleaves or scattered over the underside of the stem; fertile branches are lateral or ventral; androecia branches are spicate, and many other contrasting characters. Best to learn Geocalyx, Lophocolea, and Chiloscyphus in the field and forget about the family!

1a. Perianth present, elongate, exserted, trigonous; perigynium or marsupium lacking; capsule oblong-ovoid, the wall 4-5-stratose; rhizoids restricted to the bases of the underleaves................................................ (2)

1b. Perianth absent, more or less spicate; female inflorescence terminal; leaves bilobed; rhizoids scattered over the ventral part of the stem........................................................................................................ (3)

2a. Male inflorescence more or less spicate; female inflorescence terminal; leaves bilobed; underleaves with a subulate-acuminate tooth on each side. Lophocolea

2b. Male inflorescence undifferentiated; female inflorescence on short lateral branches; underleaves with a spinose tooth on each side. Chiloscyphus

3a. Autoicous; perianth absent, replaced by a subterranean rhizoidous perigynium (marsupium); underleaves deeply bilobed, with entire margins; gemmae absent; male bracts in 4-8 pairs. Harpanthus

3b. Dioicous; perianth present, fused with shoot-calyptra; underleaves divided, subulate; gemmae present; male bracts in 2-5 pairs. Geocalyx

Chiloscyphus

1a. Plant body transparent, pale whitish- to yellowish-green; sells at mid-leaf 35-40 x 45-60 microns; perianth lobes spinose-dentate. C. pallescens

1b. Plant body dull to deep green or often blackish; cells at mid-leaf 25-30 microns; perianth lobes entire or undulate. C. polyanthus

C. pallescens (Ehrh.) Dum. Common throughout the montane and subalpine forested areas. This is a close relative of the next, with 18 chromosomes.

C. polyanthus (L.) Corda. Common through the montane and subalpine forested areas. This species has 9 chromosomes. A variant occurring in swift-flowing streams is very dark green (var. rivularis).

Geocalyx

Geocalyx graveolens (Schrad.) Nees. We have one Colorado record: Larimer Co.: Rocky Mountain National Park, 1.2 mi N of Deer Creek junction on Hwy 34 to Estes Park. On ground, tree bases, and rotting wood in mesic Abies-Populus-Alnus woodland with abundant dead-fall and extensive seepy areas, also along the roadside, 5 June 1976, Vitt 15255 (cited by Hong). This collection represents the southernmost station for the species in North America.

Schuster says this is one of the easiest bilobed species to identify. Under the microscope, the bifid, rather large, underleaves, with the linear-lanceolate divisions nearly parallel, entirely unarmed on the outer side, are absolutely characteristic. Lophocolea may have similarly divided underleaves, but the lobes usually bear a sharp tooth on the outer side; in Geocalyx, also, rhizoids occur not only on the bases of the underleaves, but some occur scattered over the rest of the ventral side of the stem. In Lophocolea they are limited to a small area at the bases of the underleaves. . . On the postical side of the stem the fleshy perigynia are usually evident; when young they are small, spherical, and look like small tubers; when mature they are cylindrical and very prominent. No other species with bilobed leaves has such perigynia.

Lophocolea

1a. Plants pale whitish-green; leaves entire or subentire to bilobed; gemmae rarely developed. L. heterophylla

1b. Plants greenish-yellow; leaves bilobed 0.2-0.35 of leaf length; gemmae always abundantly developed along leaf margins. sometimes making the leaf ragged. L. minor

L. minor Nees. Abundant in moist forests throughout the mountains. Probably much more abundant the next.

L. heterophylla (Schrad.) Dum. Abundant in moist forests throughout the mountains.

HAPLOMITRIACEAE

We have the single genus and species. Haplomitrium hookeri is known from Mount Katahdin, Maine; Mount Washington, New Hampshire, and West Greenland. The single Colorado collection is the only one known in America south of the area of Continental Pleistocene glaciation. The discovery of this species by Norton Miller on an excursion of the American Bryological and Lichenological Society in 1973 was a cause of great celebration. Miller was already acquainted with it in the field in Greenland and knew where to look.

Haplomitrium

H. hookeri (J. E. Sm.) Nees. One collection, Boulder Co.: Green Lakes Valley, on “Haplomitrium Hill,” ***

Haplomitrium is a very strange hepatic, consisting vegetatively only of a slender stem no more than a centimeter long, the lower part of which is white and tender succulent rhizome. The leaves are remotely scattered along the stem, and are somewhat diamond-shaped, and somewhat shallowly and unequally lobed or completely entire. The cells are thin-walled, 25-40 x 30-50 microns. There is no asexual reproduction. For those who would like information about the sexuality, see the very detailed treatment of Schuster.

Schuster writes: “The chief problem with H. hookeri is not to identify it but to be able to locate it. It is a difficult plant to find in the field. The plant will not under any condition be confused with any other hepatic. It is quite likely, however, to be mistaken for a moss because of the erect growth, the lack of differentiation between lateral and dorsal leaves, and the form of the leaves.” The plant hardly appears more than a few millimeters above the ground and is lost among the welter of other low-growing plants. At Green lakes Valley it was accidentally found when Miller dug up a patch of soil and found the white, coralloid basal portion of the shoot system. Everyone who has had the joy of collecting this plant has never found more than one or a very few plants. Schuster continues: “The plant is exceedingly sensitive to drying, apparently lacking all toleration for intermittent moisture conditions.”

JUNGERMANNIACEAE

Jungermannia

“The genus is characterized by its dioicous or paroicous gametangia, prostrate to erect stems, lateral branching, abundant rhizoids, succubous, obliquely inserted marginal leaves, absence of underleaves, well-developed perianth (fusiform, pyriform, and cylindrical) usually with an abruptly constricted mouth and oval capsule with bistratose spiral elaters.”

Plectocolea and Solenostoma are now regarded as subgenera of Jungermannia.

Key to the species

1a. Perianth abruptly narrowed distally in a beaked mouth.......................................................... (2)

1b. Perianth gradually narrowed, not beaked............................................................................. (4)

2a. Perianth tubular, smooth; leaves ovate-oblong, parallel-sided. J. leiantha

2b. Perianth cylindrical, ovoid to clavate; leaves reniform-orbicular to slightly ovate, erecto-patent (subgenus Solenostoma)...................................................................................................................... (3)

3a. Paroicous; plants green; leaves orbicular to orbicular-cordate; leaf cells 25-30x35-50µm in mid-leaf. Rhizoids arising almost exclusively from ventral side of stem, not forming a bundle. J. sphaerocarpa

3b. Dioicous; plants red-purple, 1.0-1.5 mm wide, 0.8-2.0 cm long; leaf with a distinct border; cells 20-25x25-35µm in mid-leaf, with small trigones, more than one oil body per cell. J. rubra

4a. Perianth plicate above only, with elongated cells; perigynium present; rhizoids sometimes reddish-purple (Subgenus Plectocolea)........................................................................................................................ (5)

4b. Perianth plicate for almost the entire length, with isodiametric cells, perigynium lacking; rhizoids usually colorless (Subgenus Jungermannia).................................................................................................... (6)

5a. Plants usually dark green to purple; leaves oval-ovoid; oil bodies 1-4 per cell, mostly small, smooth; female bracts reflexed; rhizoids purplish or not; cuticle striate; paroicous. J. obovata

5b. Plants pale green to brownish-red; leaves circular, trigones distinct; rhizoids mostly colorless; oil bodies 4-5 per cell, verrucose, oval; cuticle smooth; Dioicous. J. hyalina

6a. Paroicous; perianth fusiform; leaves broadly elliptical, cells 20-25x25-30 µm in mid-leaf. J. pumila

6b. Dioicous............................................................................................................................. (7)

7a Plants 0.8-1.0 mm wide, 0.2-3.0 cm long; perianth ovoid or oblong-ovoid; androecia terminal; male bracts in 4-12 pairs. J. atrovirens

7b. Plants 0.5-4 mm wide, 0.3-12 cm long; perianth slender fusiform. J. exsertifolia

J. atrovirens Dum. There is one record, not verified: San Juan Co.: Silverton, 1931, reported by Frye (1937). Nomenclature from Damsholt & Vana (1977 [1978]).

J. exsertifolia Steph. var. cordifolia (Dum.) Vana. In general aspect, this elongate, black liverwort resembles Scapania irrigua. It is very common in montane and subalpine forests in wet areas. We have collections from Boulder, Clear Creek, Douglas, El Paso, Gilpin, Jackson, Larimer, Montrose, Park, Pitkin, and Summit counties

J. hyalina Lyell. This species grows “on moist sandy or clayey soil, such as the sides of ditches and forest paths, more rarely on moist, siliceous rocks (Arnell 1956). *** collections?

J. leiantha Grolle. Common on streamsides in spruce-fir forests. We have collections from Grand, Gunnison, and Larimer counties.

J. obovata Nees. This always grows on wet rocks and with us it is alpine. The dark color, purple rhizoids, reflexed female bracts, striate cuticle and paroicous inflorescence are diagnostic. We have one collection: Summit Co.: Blue Lake Dam area, Monte Cristo Creek Valley, 3,000 msm, on limestone terraces irrigated with snow melt; in tufts of Distichium capillaceum, Weber & Wittmann B-111214, !Hong, 2000.

J. pumila With. We have specimens from Boulder, Chaffee, Grand, Larimer, and Mineral counties.

J. rubra Underw. Dominant in fens in the San Juan Mountains, disjunct from California. We have collections from Hinsdale, Mineral, San Miguel, and San Juan counties.

J. sphaerocarpa Hook. We have collections from Archuleta, Boulder, Chaffee, Clear Creek, Grand, Larimer, Park, and Routt counties.

Nardia

Ref.: Hong & Vana (2000)

Nardia is characterized by its entire (in our species), succubous orbicular-reniform leaves; underleaves distinct, lanceolate to triangular; lack of gemmae; female bracts similar to the leaves; perianth very short, within bracts, with crenulate mouth and oval-globose capsule with bistratose walls. Very rare in Colorado.

1a. Plants large, 1.0-2.5 mm wide, 1.0-5.0 cm long, pale green; cells large, 25-30 c 30-40 microns in mid-leaf; oil bodies glistening and homogeneous; dioicous. N. scalaris

1b. Plants small, 0.8-1.5 mm wide, 5-0- mm long, brownish; cells small, 20-25 x 25-30 microns in mid-leaf; oil bodies granular and opaque. N. geoscyphus

Nardia geoscyphus (Trevis.) Vana. Two collections known: Boulder Co.: Green Lakes Valley, Indian Peaks, Gritstone 2263 (COLO). !Vana, Hong; Kiener 3377 (YU), !Hong. Both of our species have entire, emarginate leaves).

N. scalaris S. Gray. One collection known: “Colorado”, Roll (BM).

LEPICOLEACEAE

Gymnocolea

G. inflata (Huds. Dum. There is only this one species, and it is probably the most common, even dominant hepatic in subalpine fens, especially in shallows or around the edges of rock pools. It is a tiny dark brownish or blackish thing producing simple, unbranched stems. The colonies are usually very dense. The leaves are incubous but hardly overlapping, almost round, shallowly two-lobed above the middle and the leaf lobes curve in, cup-like. There are no underleaves The perianth is an inflated football with several short broad teeth around the narrow mouth. The leaf cells are uniformly thick-walled, without trigones.

LEPIDOZIACEAE

Ref.: Hong (1988b)

The Lepidoziaceae is a family notable for having genera with variously terminally toothed or multi-cleft leaves, some having the leaves so deeply and narrowly divided that they look like cottony ropes! The simplest type in the West is Basinet, which has the leaves with three terminal teeth, and variously toothed underleaves. Basinet does not come into our range.

Lepidozia

L. reptans (L.) Dum. Schuster says: “The incubous leaves, with the apices decurved and 3-4-lobed, giving them the appearance of a cupped hand (when seen ventrally), at once identifies this species. This, together with the frequent presence of terminal flagella-like branches and the regularly pinnate branching, serve to characterize this species in the field.

This is an uncommon plant, but possibly it is overlooked because it is so small and tends to grow on rotting logs. We have two specimens: Boulder Co.: Sandbeach Lake trail, 2 mi W of Copeland Lake, Rocky Mountain National Park, Hermann B-27389; Larimer Co.: on rotting wood in the stream, Hidden Valley, Weber B36502, 56609.

LOPHOZIACEAE

1a. Leaves all or largely 3-4-lobed, at least on well-developed shoots, underleaves sometimes present; perianths plicate.............................................................................................................. (2)

1b. Leaves all or nearly all bilobed on sterile shoots; underleaves lacking..................... (3)

2a. Leaves all or mostly 4-lobed, nearly flat; plants growing horizontally, with the leaves at about a 15-30° angle with stem, nearly horizontally spreading. Barbilophozia

2b. Leaves 3- or 2-lobed (a least in part 3-lobed), concave; plants erect or nearly so with the leaves inserted at a 40-60° angle with the stem; leaf lobes usually incurved. Tritomaria

3a. Perianth cylindric, with the apex suddenly and abruptly truncated into a short beak. (See Leiocolea)

3b. Perianth distinctly plicate, gradually narrowed, never beaked. Lophozia

Barbilophozia

The most easily recognized group of species in the family is Barbilophozia. The plants are fairly large, that is, they are elongate creeping plants with leaves that are not densely crowded into heads. Their leaf arrangement is succubous, and the leaves are large enough and spreading enough to tell with a hand lens that they are distinctly 4-lobed. L. hatcheri is the species most frequently encountered from the foothills up into the montane. Unless you are very myopic, the leaves need to be examined with a microscope (see the key). With experience some of them can be recognized on sight.

1a. Leaves concave, obliquely inserted...................................................................................... (2)

1b. Leaves nearly flat, horizontally inserted................................................................................. (4)

2a. Leaves mostly 2-3-lobed, the sinus descending 1/4-1/3 of their length; plants with attenuated erect shoots whose leaves are smaller and appressed. B. attenuata

2b. Leaves mostly 2 (rarely 3,4)-lobed, the sinus descending ½-3/5 of their length...................... (3)

3a. Leaves divided into two (occasionally 3, 4) lobes; sinus descending about ½ of their length; lobes blunt to sub-acute. B. kunzeana

3b. Leaves divided into three lobes, the sinus descending less than 1/3 of their length; lobes sharply acute. B . floerkei

4a. Postical leaf bases lacking cilia; underleaves rare or none and little or not ciliate; leaves never mucronate-tipped or apiculate; gemmae absent; leaves symmetrical, with more or less triangular lobes. L. barbata

4b. Postical leaf bases with a few distinct cilia, formed by several cells 3-10 times as long as wide; underleaves present, ciliate; at least some leaves mucronate-tipped....................................................................... (5)

5a. Leafy shoots normally 1.5-2.7 mm wide; brown gemmae very common on the proximal leaves; leaves flat, the lobes ovate-triangular, usually mucronate. L. hatcheri

5b. Leafy shoots normally 4-5 mm wide and 4-8 cm. long; gemmae very rarely present; leaves undulate-crispate. B. lycopodioides

B. attenuata (Mart.) Loeske. Frye & Clark cite specimens (as Orthocaulis gracilis)from “Silverton, 1931, Frye”, and “Longs Peak, Kiener.” This needs to be verified. Hong does not mention the species.

B. barbata (Schreb.) Loeske. Frequent in the subalpine and upper montane forests. The least common of the three species.

B. floerkei (Web. & Mohr) Loeske.Evans (1915) reports this from “Pikes Peak, 1896, Holzinger.”

B. hatcheri (Evans) Loeske. By far the most common species in the foothills and montane zone. In the mature subalpine spruce forests it is largely replaced by L. lycopodioides, a very handsome and conspicuous species in comparison.

B. kunzeana (Hüb.) Müll. Evans (1915), reported a collection: El Paso Co.: Minnehaha, 1913, G. E. Nichols.

B. lycopodioides (Wallr.) Loeske. A beautiful, large species characteristic of forest floors in mature, relatively undisturbed moist subalpine spruce forests. It is like a large edition of L. hatcheri but differs in its undulate leaves and lack of gemmae.

May 8, 2003 Leiocolea

Ref.: Hong (2002b). We have no first-hand knowledge of the genus and are paraphrasing material from the cited reference.

Fertile plants of this genus are very easy to recognize in the field. It is the only bilobed group of liverworts having smooth, cylindrical perianths whose apices are suddenly constricted into a distinct, short beak. A similar beak occurs in Jungermannia, but in that genus the leaves are entire.

1a. Plants small (less than 1.0 mm wide and 12 mm long); underleaves absent. L. badensis

1b. Plants large (over 1.0-5.0 mm wide and 1.0-8.0 cm long); underleaves present.................... (2)

2a. Gemmae present. L. heterocolpos

2b. Gemmae absent.................................................................................................................. (3)

3a. Leaves bilobed up to 25 per cent; cells large, 35-40 x 40-55μm in mid-leaf. L. bantriensis

3b. Leaves bilobed more deeply; cells small, ca. 25-30 x 25-35μm in mid-leaf. L. collaris