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times on the trunks of trees. Stems varying in size from a few lines to several inches, growing in tufts, more or less dense and extensive, either loosely cohering or matted together by the numerous radicles clothing all parts of the stem, which increases by means of fastigiate innovations from below the flowering summit.
Leaves in 5 or 8 rows, more or less crowded, spreading or secund, often falcato-secund, when dry straight or crisped, broadly lanceolate, linear-lanceolate, or lanceolato-subulate, entire, or serrated near the apex, smooth, or papillose on the surface, the nerve semi-cylindrical, either excurrent or ceasing at or below the apex. Reticulation variable, usually small, dot-like, or roundish in the narrower part of the leaf, elongated, narrow, and often wavy lower down, at the marginal base considerably enlarged, quadrate, and more or less deeply coloured. Inflorescence (except in one androgynous species) monoicous or dioicous, terminal. Perigonia (barren-flowers) gemmiform, or capituliform, with 3 to 9 leaves surrounding the oblong, shortly pedicellate antheridia. Paraphyses yellowish, filiform. Fertile flower gemmiform, the involucre at length changed into a perichætium. Archegonia with long styles, accompanied by shorter paraphyses. Perichetium more or less closely sheathing, its leaves longer, wider, and of thinner texture than the stem leaves, with a narrower fainter nerve.
This extensive genus (named from depavov, a forked instrument) presents so many diversities in the mode of growth, in size, in the form and direction and texture of the leaves, in the position of the flowers, and in the form and direction of the capsule, that at first sight a subdivision into two or more genera would seem both easy and requisite. But we agree with Bruch and Schimper in the conclusion that the more the species are studied as a whole, they will be found too closely related to admit of dismemberment.
The smaller species are not much unlike the Weissie, while the larger ones approach in some cases the Trichostoma and Cynodontium. The genus contains some species scarcely surpassed in size by any of the acrocarpous division of the order.
In several of the larger species of Dicranum which have the stem covered with a dense layer of radical fibres, the barrenflowered plants appear to be replaced by minute buds, nestling among the fibres; and up to the present time this is all that is known of the barren inflorescence of certain species ; but in D. scoparium the inflorescence may sometimes be traced from these radicular gemmæ up to the perfect development of detached barren-flowered plants. A somewhat analogous process is observable also in a few species of Hypnum.
We follow the admirable arrangement and subdivision of the genus given in the Bryologia Europea.
Sect. I. Polycarpa. Growing in soft tufts, two inches high, repeatedly forked; branches fastigiate, and rooting in all parts of the stem. Leaves spreading every way, flexuose, crisped when dry, linear-lanceolate, papillose on both sides, crenulate in the margin, nerve ceasing below the apex. Inflorescence monoicous. Capsule ovate, or oval, (its neck symmetrical or strumose,) striated. Calyptra whitish, somewhat inflated. Lid with a beak shorter than the capsule.-D. gracilescens (not found in Britain). D. polycarpum.
Sect. II. Virentia. Cæspitose. Stems rooting in all parts, twice or thrice dichotomous, usually decumbent, densely and uniformly leafy. Leaves spreading and squarrose, slightly crisped, lanceolate, smooth, opaque, entire, or subdenticulate at the apex only ; nerve slightly excurrent, monoicous. Capsule cernuous, gibbous, and slightly curved, smooth, the neck decidedly strumose, walls of the capsule composed of minute irregular roundish-hexagonal cellules. -D. virens.
Sect. III. Squarrosa. Loosely tufted, rooting in the axillæ of the lower leaves. Leaves squarrose, widely lanceolate, entire or denticulate at the apex; nerve ceasing be w the apex. Dioicous. Barren fl. capituliform. Capsule cernuous, smooth ; neck short, tumid, but not strumose.
a. With papillose denticulate leaves. D. pellucidum.
Sect. IV. Crispa. Subcæspitose. Stems short, rooting in the lower part. Leaves subsquarrose, crisped when dry, sheathing at the base, lanceolate or subulate above, smooth and somewhat glossy, more or less denticulate or serrulate at the apex ; nerve either excurrent, or ceasing near the apex. Inflorescence monoicous or dioicous. Barren fl. capituliform. Capsule cernuous, smooth or obscurely striated, with or without a strumose neck.
a. Dioicous. D. Schreberi.
Sect. V. Rufescentia. Stems short, gregarious, scarcely cespitose. Leares more or less secund, lanceolate, opaque, entire or obscurely dentate; cellules oblong, rather large. Dioicous. Capsule erect or somewhat inclined, without striæ. Annulus none. Lid large, with a short beak. Peristome large in proportion to the size of the plant.-D. varium. D. rufescens.
Sect. VI. Heteromulla. Cæspitose, about an inch high. Leaves secund, glossy, lanceolato-subulate, entire ; nerve predominant above, flattened. Dioicous. Capsule cernuous, or suberect, uniformly coloured or striated; neck symmetrical or strumose. Lid conical at the base, with a long beak.-D. cerviculatum. D. subulatum. D. curvatum (not Britislı). D. heteromallum.
Sect VII. Falcata. Densely tufted. Stem taller, repeatedly dichotomous and fastigiate, usually decumbent at the base, with few or no radicles. Leaves secund, or falcato-secund, lanceolato-subulate, entire, or denticulate, glossy; nerve predominant above, as in the last section ; cellules of the marginal base much enlarged and coloured. Monoicous. Capsule cernuous (neck strumose or ventricose), uniformly coloured or striated. Lid with a long beak.-D. Blyttii. D. Starkii. D. falcatum.
Sect. VIII. Orthocarpa. Densely cæspitose. Stems one or more inches high, twice or thrice dichotomous, everywhere coated with radicular fibres. Leaves secund, rarely directed to all sides, lanceolato-subulate, smooth, glossy ; nerve excurrent; cellules narrow, much enlarged, quadrate, and reddish-brown at the marginal base. Monoicous. Capsule erect, cylindrical ; neck longer than usual, symmetrical. Lid conical at the base. Peristome small.-D. strictum. D. montanum. D. flagellare.
D. flagellare. D. interruptum. D. Scottianum. D. Sauteri. D. longifolium. Of these only one species (D. Scottianum) is found in Britain.
Sect. IX. Scoparia. Growing in broad and tall patches, loose, or densely matted together. Stems tall, handsome, everywhere covered with proliferous radicular fibres. Leaves long, spreading every way, or secund, lanceolato-subulate, glossy, denticulate at the apex, loosely cellular, with quadrate areolæ at the base ; nerve with or without dorsal lamellæ. Dioicous, or quasi-monoicous. Peria chutium cylindrical, enclosing one fruitstalk. Capsule cernuous, bent.
Lid with a long beak. — D. scoparium. D. elongatum (not found in Britain). D. fuscescens Turn. D. Mühlenbeckii (not British). D. palustre.
Sect. X. Spuria. Cæspitose. Stems tall, everywhere beset with radicular fibres. Leaves spreading every way, glossy, ovate-lanceolate, transversely undulated ; nerve flattish, rugose at the back near
the apex; cellules as in the section Scoparia. Barren flowers not observed (dioicous ?). Perichætium closely sheathing, with one fruitstalk. Capsule cernuous, curved. Peristome rather small. — D. Schraderi. D. spurium.
Sect. XI. Undulata. The tallest and most showy of the genus, growing in large patches. Stems everywhere beset with whitish radicular proliferous fibres. Leaves large, glossy, spreading every way, or secund, lanceolate below, linear-subulate above, transversely undulated, or even; nerve fattish, with lamellæ at the back. Perichatium long, containing several fruitstalks. In other respects as in the two previous sections. — D. undulatum. D. robustum. D. majus (of these only D. majus is found in Britain).
Since the publication of the above in Bryol. Eur., C. Müller (in Synops. Musc.) has removed the species of Sects. II., III., IV., V., and VI., into a separate group, Leptotrichaceæ, and into the genus Angstremia, said to be distinguished from Dicranum by the cucullate calyptra, and by the absence of the enlarged diaphanous cellules (cellulæ alares) at the marginal base of the leaf, which characterise the Dicranacece.
Sect. I. POLYCARPA. 1. Dicranum polycarpum Ehrh. (many-fruited Fork-Moss); stems elongated ; leaves more or less crowded, spreading, flexuose or recurved, linear-lanceolate or lanceolato-subulate, keeled, margin recurved, scarcely papillose, serrulate at the apex; capsule erect and equal, or cernuous, gibbous, and stru. mose at the base, striated; lid rostrate. (Tab. XVIII.)
Dicranum polycarpum Ehrh. Decad. Smith, Fl. Brit.
Eng. Bot. t. 2269. Mougeot and Nestler, n. 414.
Musc. 2. 591.
Oncophorus polycarpus Brid. Bryol. Univ. i. 397. var. B. strumiferum ; capsule unequal, strumose at the base. D. strumiferum Web. and Mohr. Schwaegr. Hook. and
Tayl. (TAB. XVII.) C. Müller, Syn. Musc. ii. 592.
Oncophorus strumifer Bridel. Hab. Alpine rocks, not frequent. Cader Idris, Mr. Ralfs.
Clova Mountains. Ben High, G. Don. Bushiel Dene, Berwickshire, Mr. James Hardy. Rocks in Humbledon Dene, abore Wooler, Dr. G. Johnston. var. B. Glen Phee, Clova.
Fr. July, August.
Stems cæspitose, about 1 inch high, more or less. Leaves variously bent, often recurved, somewhat twisted when dry, gradually enlarged towards the summit of the stem, somewhat papillose or granular on both sides, margin reflexed, denticulate at the apex and at the base, nerve subexcurrent. Capsule on a straight fruitstalk, ovate-oblong, erect, symmetrical in the typical form of the species, the neck slightly tumid; unequal, inclined and strumose at the base in the var. B., striated, especially when dry. Calyptra reaching nearly to the base of the capsule. Lid obliquely rostrate, shorter than the capsule. Annulus distinct. Peristome variable; teeth deeply cloven or variously perforated, reddish brown. Barren flower at the base of the perichætium.
D. gracilescens Web. and Mohr, frequently confounded with this species, differs in having more slender stems, and shorter, softer, more papillose leaves, which have the margins plane not reflexed in the upper half, the capsule shorter, more regular, and never strumose.
D. alpestre Wahlenb. is considered by Bruch and Schimper to be only a small state of D. gracilescens, on the authorfty of specimens from Wahlenberg. In the Hookerian Herbarium, however, there is an authentic specimen from Wahlenberg which is scarcely distinguishable in aspect from Rhabdoweissia Schisti, differing only in the peristome, which is truly that of Dicranum, and in the obtuse leaves. It appears to be a distinct species.
D. polycarpum much resembles Cynodontium Bruntoni, but is easily known by the striated capsule.
Sect. II. VIRENTIA. Angstræmia C. Müller. 2. Dicranum virens Hedw. (green spur:fruited Fork- Moss); stems elongated, loosely tufted, twice or thrice dichotomously branched ; leaves spreading, erect, and slightly sheathing at the base, lanceolate, incurved when dry, smooth, opaque, their margins recurved; capsule cernuous, smooth, oblong, curved, distinctly strumose ; lid rostrate. (Tab. XVII.)
D. virens Hedw, St. Cr. t. 32. Schwaegr. Turn. Smith,
Eng. Bot. t. 1462. Web, and Mohr. Hook. and Tayl.
Br. and Sch. Monogr. p. 15. t. 3, 3*.
Angstroemia virens C. Müller, Syn. Musc. ii. 609.
Fr. June, July Stems often 3 inches high, with scattered radicular fibres. Leaves ovate-lanceolate, erect and slightly sheathing at the base, linearlanceolate and spreading in the upper half, incurved but not crisped when dry, reflexed in the margin, entire or subdenticulate at the apex; nerve thicker than in the last species, subexcurrent. Perichatial leaves larger than the rest, and more sheathing. Capsule cernuous, curved, oblong, with a distinct struma at the base, reddishbrown, smooth without striæ, slightly constricted below the mouth when dry and empty. More robust than the D. polycarpum, the leaves firmer, broader below, glossy, much less crisped when dry, with a thicker nerve. It varies, according to Bruch and Schimper, as follows: