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Readily distinguished from the last by its longer acute leaves, distinct
perichætium and shorter capsule, and it is also confined to the more elevated
mountains. When growing exposed to the constant drip of snow water it
assumes a black colour and the leaves and capsules are shorter, it then
becomes the var. atrata N e e s H s c h . and connects itself to D. compacta
( S c h l e ic h .), which has been recorded from Ben Lawers, but the specimen
we have received is not the plant ; D. compacta also is properly regarded by
Lindberg as a var. of D. crispula.
D IC R A N U M H e d w .
Fund. musc. II, 91 (1782).
Plants usually ta ll and handsome, dichotomous, rooting only at
base, or the whole stem covered with radicular tomentum. L e a v e s
patent or falcato-secund, smooth or ra rely papillose, g los sy or opake,
lon g and lanceolate or lanceolate-subulate ; nerve semiterete or more or
less dilated ; areolation narrow and e longated re c tangular in the lower
part, with the angular c e lls quadrate dilated v es icular and colored
orange or brown, above lineal-oblong quadrate or ellip tic, often
flexuose ; perich. b ra c ts sheathing. Cap s, e re c t or cernuous, ra rely
striate, with a short equal neck, ra rely strumose, g ene rally annulate ;
lid rostrate ; teeth 16, orange or deep red, confluent a t base, c le ft h a lf
w a y or more into 2 — rarely 3 — unequal subulate legs, s triolate at
base, trabecula te internally ; ca lyp tra cu cu lla te , rostrate, usually falling
with the lid. Male infl. gemma ceous. Inhabiting the ground, ro ck s or
ra rely trunks o f trees. D e r iv .— hupavov a fork.
This very natural genus comprises about 100 species, varying
considerably in size ; and also in general aspect. As originally established
by Hedwig, when the peristome was regarded as affording almost the sole
essential character, it included a miscellaneous collection— Ceratodon purp.,
Leucobryum, Grimmia acicnlaris, Dicranella heteronialla, Dichodontium pellucidum
and Dicranum scoparüm— the last being retained as the type of the genus.
In the highest developed forms D. undulatum, Bonjeani, scoparhmi, &c.
constituting Lindberg’s section Eudicrammi, the longitudinal walls of the
leaf-cells will be seen, by proper amplification, to be perforated by fine pores,
by means of which the cells communicate ; these are wanting in the other
sections, and in the few species which have papillose leaves as D. montanum,
the papillæ are simple conical elevations of the cell-cuticle ; the vesicular
colored angular cells are the most characteristic feature in this genus.
On the felted mass of radicles which clothes the stem of several species,
small tubercles form which develope into male gemmæ, and in D. scoparmm
grow on into independent male plants.
The other European species are D. hyPerborenm, Anderssonii, elatum,
undulatum, fragilifoUzim, strictum, Muehlenheckii, hrevifolium, fnlvmn, albicans and
comptum ; of these D. undidatum is a species which ought to occur here, being
found in alpine woods throughout Europe and N. America, but although it
has been several times reported from various localities, no genuine specimen
has yet come before us ; it is closely allied to D. Bonjeani, but has aggregated
setæ like D. majus.
Several species are extremely variable, and again others are very
much alike, so that considerable difficulty is experienced by beginners in
their correct determination ; this will be best overcome by a careful study of
the areolation of the lea f and of transverse sections of the nerve.
C l a v is t o t h e S p e c ie s .
Sect. I . A r c t o a . Plants autoicous, radiculose only at base; leaves lane.-subulate, entire.
Capsule small with a tapering or strumose neck.
Capsule erect, neck tapering. fulvellum.
Capsule cernuous, neck strumulose.
Capsule short ovate.
Leaves flexuose patent. schisti.
Leaves falcato-secund. falcatum.
Capsule oblongo-cylindric.
Leaves falcato-secund, lid long-beaked. Starkei.
Leaves erecto-patent, lid short-beaked. violle.
Sect. 2. E u d ic ra n u m . Plants robust, dioicous or pseud-autoicous, tomentose ; leaves
lanceolate, the longitudinal walls of their cells communicating by fine pores. Caps, cernuous,
cylindraceous, more or less arcuate.
Leaves not undulate.
Setæ aggregated, nerve serrated at back towards apex. majus.
Setæ solitary, nerve 4-winged at back above. scoparium.
Leaves transversely undulate.
Leaves smooth at back, gradually elongated.
Upper cells elongated, nerve smooth at back. Bonjeani.
Upper cells small quadrate, nerve serrate at back above. Bergeri.
Leaves papillose at back, short and broad, suddenly acuminate, spurium.
Sect. 3. A p o r o d ic ty o n . Plants of medium size, radiculose ; leaves lane.-subulate, their
cell-walls not interrupted by pores. Caps, cernuous or erect, cylindraceous, curved or symmetric.
Capsule cernuous, curved.
Leaves patent, quite entire.
Leaves secund, serrulate.
Nerve | — i width of base, iorming all apex.
Nerve 4 width of base, not excurrent.
Capsule erect, symmetric.
Leaves curled when dry, nerve vanishing at the serrulate apex.
Subula short, papillose at back.
Subula elongated, smooth at back.
Leaves scarce altered by drying, nerve excurrent.
Leaves gradually narrowed into a subula.
Apex quite entire, elongated ; lower cells incrassate. Scottii.
Apex quite entire, broken off ; lower cells lax, hyaline, viride.
Apex serrulate, longly subulate ; lower cells lax, very long. Sauteri.
Leaves suddenly narrowed into a very long setaceous point.
Leaves falcato secund.
elongatum.
fuseeseens.
congestum.
montanum.
flagellare.
Nerve half width of base, serrate at back.
Nerve 4 width of base, smooth at back.
Leaves erecto-patent, spinulose at back of point.
S e c t . i . A R C T O A S c h im p .
I . DICRANTJM TTTLVELLUM {Dicks.) Sm.
A u to ico u s ; short, densely tufted. Le a v e s secund,
longifolium.
uncinatiim.
asperulum.
lanceolate