BFNA Title: Trichocolea
Author: P. M. Eckel
Date: March 10, 2017; March 28, 2019
Edit Level: S
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden
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Patricia M. Eckel


Plants forming thick mats ; branches usually replacing ventral half of a lateral leaf; without [with] tapered, flagelliform distally microphyllous lateral branches . Leaves alternate, succubous [weakly incubus], plane, deeply lobed, with lobes divided into a mass of branched uniseriate cilia; underleaves large, deeply lobed, with lobes divided into a mass of 1-seriate cilia. Stems often covered with filamentous paraphyllia. Rhizoids absent or rarely present as hyaline tufts restricted to underleaf bases. Specialized asexual reproduction absent. Gynoecium terminal or on an ordinary leafy branch, often subtended by 2 subfloral branches. Perianth absent [present and rudimentary]. Perigynium erect, clavate, an epicoelocaule [cryptocoelocaule, shoot calyptra], bearing old archegonia [laterally or] near its tip.


Genera 3 (1 in the flora):  eastern North America, Mexico, West Indies, Central America, South America, Eurasia, Africa (Tunisia), Pacific Islands, Australia.


Trichocoleaceae occur in areas rich with bryophytes, and include terrestrial species, with habitats including trunks and branches of trees, and on soil in shaded, moist evergreen (Nothofagus) or deciduous forests and tropical or subtropical lowland to montane rainforests. The family is characterized by their highly ciliate leaves and by having their sporophytes associated with erect perigynia , i.e., structures that are derived from the stem tissue just below the fertilized archegonium that replace either a part or all of the calyptra, with or without an associated perianth.


Perigynial structures in the family include the epicoelocaule, in which the sporophyte is completely enclosed by stem tissue, and both perianth and calyptra are lacking.. The family also displays two structures with perianths: the cryptocoelocaule, and the shoot calyptra (with perigynial tissue at its base). The epicoelocaule alone occurs in two of the three genera in the family, and is the structure characteristic of Trichocolea. In Trichocolea the epicoelocaule surface is hispid proximally with reduced fragments of scattered bractlets and paraphyllia throughout, unfertilized or aborted archegonia at the apex, and bracts and bracteoles at the base. Other characters of the family include elongate, thin-walled leaf cells lacking corner-thickenings.


The three genera (Eotrichocolea, Leimomitra and Trichocolea) are supported as comprising a monophyletic family in the molecular phylogenetic analysis of D. Glenny et al. (2009).


SELECTED REFERENCES  Glenny, D., J. J. Engel and X. He-Nygrén. 2009. The systematic identity of Chiloscyphus trichocoleoides, a new liverwort species from New Zealand, uncovered by morphological and molecular evidence. J. Bryol. 31: 93--105.  Katagiri, T.and H. Deguchi. 2012. Taxonomic studies of the Trichocoleaceae in Southeast Asia. I. The genus Leiomitra Lindb. Bryologist 115: 474--491.  Katagiri, T., M. Suleiman and H. Deguchi. 2012. Taxonomic studies of the Trichocoleaceae in Southeast Asia II. A new species of Eotrichocolea from Malaysia. Bryologist 115: 518--522. Katagiri, T., A. Sadamitsu, H. Miyauchi, H. Tsubota and H. Deguchi. 2013. Taxonomic studies of the Trichocoleaceae in Southeast Asia. III. The genus Trichocolea Dumort. Hattoria 4: 1--42.



1. TRICHOCOLEA Dumortier, Commenat. Bot., 113. 1822, orth. cons. “Thricholea” * [Greek thrix, ‘hair,’ and koleos, ‘sheath,’ alluding to the hairy, fleshy, sheath-like stem perigynium surrounding the sporophyte during its development.]


Plants in tufts, loose to dense mats or interwoven among other bryophytes, prostrate to ascending, whitish to yellowish green, paler when dry, secondary pigmentation lacking [reddish, orange to brownish], growth monopodial. Stem with lateral terminal branches of the Frullania-type, i.e. bearing dorsal half-leaves inserted just below the branch and having half the number of lobes of the regular leaf, i.e. 2-fid; branches regularly [irregularly] [1--]2--3-pinnate;  stem cross section more than 12--16[--35] cells in diameter, nearly homogeneous,epidermal cells [strongly to] subdistinct, in 1--2[--7] layers, somewhat smaller with thicker walls than the larger, very thin-walled cortical cells; cuticle [strongly papillate- to] rather weakly striolate- verruculose;  paraphyllia abundant [absent ], uniseriate, often branched, on dorsal surface of stems and branches. Rhizoids, when present, colorless, distal ends digitate. Lateral leaves succubous, subobliquely to subtransversely inserted, distant, contiguous to imbricate on the branches, semi-amplexicaulous, asymmetric, subconcave, the smaller ventral part of leaf subtransversely inserted on the ventral side of the stem; undivided leaf lamina (disc) (1--)3--4(--18) cells high, divided unequally into (3--)4--5(--9) triangular lobes, the lamina without [with] superficial cilia, irregularly bifurcately branched, narrowed into masses of long 1-seriate or 2-furcate cilia, margins densely laciniate-ciliate, cilia linear-subulate, (2--)4--6 cells long, septa not dilated [dilated], not fragile [fragile], distal ends not thickened [thickened, cap-like], leaf cells mostly rectangular, equally thin-walled, lacking trigones, with the cuticle weakly verruculose-striate [strongly papillate]; oil bodies small, distinct, without [with] an ocellus. Underleaves large, similar to lateral leaves but smaller, as wide as the stem or wider, insertion transverse, symmetrical, twice 2-fid, appearing deeply 4-lobed nearly to the base, the lobes as densely laciniate-ciliate as the lateral leaves. Specialized asexual reproduction unknown, cilia intact [fragile and fragmenting in one exotic species]. Sexual condition dioicous. Antheridial plants, not distinct from vegetative, and smaller than archegoniate plants. Androecia terminal on primary branches, bracts similar to the leaves but smaller, in (9--)12--15(--16) pairs, closely imbricate, weakly concave at the base, each bract subtending (1--)2 large, globose antheridia with 2-seriate; bracteoles similar to the underleaves, lacking antheridia. Gynoecia terminal on primary or elongate lateral branches, pseudolateral due to the development of (1--)2 subfloral branches; with bracts and bracteoles in 3 imbricate cycles; bracts and bracteoles larger than but similar to the leaves and underleaves except more densely ciliate and more shallowly and frequently lobed, surrounding the otherwise naked archegonia which are immersed in a dense mass of paraphyllia. Perianth and calyptra absent. Stem perigynium erect, fleshy, clavate, an epicoelocaule,, bracts and bracteoles inserted below epicoelocaule base, elongating surface bearing dense proximal rudimentary bractlets, receptacular paraphyllia, and distally unfertilized or aborted archegonia. Sporophytes massive, foot obconoidal, seta long, thick; capsule narrow, ellipsoidal, regularly dehiscing into 4 valves; capsule walls in 4--7 layers, outer walls without or rarely with linear to semiannular thickenings; inner layers of smaller cells with nodular semiannular and annular thickenings. Elaters free, 2(--3)-spiraled,0.1--0.2 mm, reddish brown. Spores orbicular-ovoid, reddish brown to brown, 10--14(--18) /um, smooth or minutely granulate.


Species 20 (1 in the flora): e North America, s Mexico, West Indies, Central America, South America, Eurasia, Africa (Tunisia), Pacific Islands, Australia.


Trichocolea is separated from other genera in the family “by the regularly 1--3-pinnate habit; the obliquely to subtransversely inserted leaves, the succubous leaf insertion, the stem cortex of 1--5 layers of leptodermous cells, the epicoelocaule with perianth absent and ellipsoidal capsule dehiscing into four regular valves” (Katagiri et al. 2013). Both the similar ciliate-leaved genera Ptilidium and Blepharostoma frequently develop fruiting structures, and have well-developed perianths, not a fleshy, paraphyllose stem-derived perigynium as in the rarely-fruiting Trichocolea. Ptilidium has incubous (not succubous) leaves with smooth, thick-walled leaf-cells and bulging trichomes, rhizoids evident on the stem, and lacks paraphyllia. Blepharostoma trichophyllum is autoicous (or paroicous) has leaf lobes completely 1-seriate-ciliate throughout, the leaf cells thick-walled and with 1-seriate chains of gemmae at the leaf apices. While Trichocolea is conspicuously regularly 2--3-pinnate in branching, Ptilidium is irregularly 1--2-pinnate, and Blepharostoma is only sparingly branched.


SELECTED REFERENCES  Hatcher, R. 1957. The genus Trichocolea in North, Central, and South America (Hepaticae). Lloydia 20: 139-185.  Hatcher, R. 1959. The structure of the female inflorescence and its taxonomic value in the genus Trichocolea. (Hepaticae). Lloydia 22: 208-214. Katagiri, T., A. Sadamitsu, H. Miyauchi, H. Tsubota and H. Deguchi. 2013. Taxonomic studies of the Trichocoleaceae in Southeast Asia. III. The genus Trichocolea Dumort. Hattoria  4: 1--42. R. M. Schuster. 1966. Hepaticae and Anthocerotae of North America East of the Hundredth Meridian, Vol. 1. Colombia Univ. Press, New York. 802 pp..


1. Trichocolea tomentella (Ehrh.) Dumort., Syll. Jungerm. Europ., 67. 1831


Jungermannia tomentella Ehrh., Hannover. Mag. 21: 277. 1783; Trichocolea biddlecomiae Austin


Plants robust, constantly light grayish to yellowish green above a brownish base, 5--13 (--16) cm long, the entire plant 1--2.5(--3) cm wide; branches growing loosely, procumbent, suberect or ascending, in loose or dense hummock-like mats. Stem diameter ( 0.4--)0.6-- 0.75(--1.5 mm) wide, regularly 2--3-pinnate. Lateral leaves to 1 mm x 2 mm, unevenly divided 0.5--0.9 of their lengths into 4--5(--8) very narrow lobes, undivided lamina (disc) to 3 cells high, lacking surficial cilia, the margin densely ciliate; cilia of leaves not fragile, linear, (3--)4-6(--7) cells long, uniformly thin-walled, terminal cells straight, only somewhat longer than penultimate cells, septa thin-walled, flat. Oil bodies small, (3--)6--8(--10) per cell, faintly granular or with spherules.


Neutral to calcareous substrates, absent from acid habitats such as peat bogs, terrestrial on constantly moist to wet (not inundated), usually humus-rich soil, in (cedar) swamps in depressions, on rotted stumps and trunks, in peaty hummocks, on the slopes and banks of streamlets, on diffusely shaded rocks in humid to wet deciduous woods; less common in ravines on vertical rocks, ledges and banks in dripping wet habitats, best developed into dense, deep mats in swamps; absent from the trunks of trees; 0--1200(--3000) m; Miquelon; Nfld., N.S., Ont., Que.;  Ark., Conn., D.C., Del., Fla., Ga., Ill., Ind., Iowa, Ky., Maine, Mich., Md., Mass., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis; Europe; Asia; Africa (Tunisia); Atlantic Islands (Azores); Pacific Islands.


Antheridate plants of Trichocolea tomentella are reported to be very rare, or are inconspicuous. Plants with sporophytes are very rare perhaps due to sexually disjunct populations; female plants are somewhat more frequent, the gynoecium inconspicuous, hidden in dense paraphyllia but are also often overlooked. Trichocolea tomentella is distinct by the regularity of the 2--3-pinnate habit, the stem epidermis weakly distinguished, leaf lobes more than three, leaf lamina divided to more than one-half, eciliate laminal (disc) surfaces, cells thin-walled and weakly striolate-verruculose throughout the plant, the septa of the cilia not enlarged, and the lack of an eye-spot in the oil-bodies. The pale pigmentation helps distinguish the species from the more highly colored mosses and liverworts with which it is found in nature.