ON THE OCCURRENCE OF DICRANDM FLAGELLARS. 27 



The following description of D.flagellare is taken from English 

 specimens : — Stems ^ to 1 inch high, slightly branched in a forked 

 manner, and matted together by reddish fibres into extensive tufts. 

 Leaves yellowish or full green, spreading and slightly arched, form- 

 ing a tuft at the apex of the branches after the manner of D. sco- 

 parium. In those specimens which bear jlagellce the leaves are 

 nearly erect and straight, and the tufts are more compact and 

 fastigiately branched. All the leaves have the margins connivent 

 from near the base, so that one half of the lamina is folded over 

 the other, the leaf thus presenting a tubular and subulate ap- 

 pearance. Apex minutely serrulate, with about three tolerably 

 distmct teeth on each side ; the back of the nerve near the apex 

 is also minutely serrulate. The nerve sometimes appears to 

 vanish just below the apex of the leaf, but is often prolonged to 

 its apex. In the lower half of the leaf the lamina is about 2^ 

 times as broad as the nerve, and consists of oblong cells, which 

 have rounded or sometimes oblique ends. The cells become 

 quadrate above, and only half the size of the oblong cells in the 

 lower part of the leaf. The alar cells are large and quadrate, 

 brown if the leaf has been taken from a comal tuft, and form a 

 distinct patch extending to the nerve. There are generally eight 

 rows of these cells, the two rows nearest the margin of the leaf on 

 eithe? side having narrower cells than the rest. In the young 

 leaves the alar cells are scarcely coloured, and pass gradually into 

 the oblong cells. The nerve is rather flattened, and appears to 

 gradually blend with the lamina on account of having next to it 

 on either side throughout its length one or two rows of very narrow 

 cells. 



The fruit has not yet been found in Britain, therefore the fol- 

 lowing descriptions of it are taken from Hedwig's and Bruch and 

 Schimper's works. 



Male flowers — Arranged in terminal heads among the uppermost 

 leaves ; the perichetial leaves ovate-lanceolate, containing antheri- 

 dia mixed with paraphyses, which have the cell at the apex obtuse. 

 Female flowers — Terminating the stems and adult innovations ; the 

 two outer perigonial leaves short, obtuse, and nerveless, the two 

 inner convolute and apiculate, furnished with a slender nerve, the 

 inmost leaf resembling the two outer ones. Archegonia without 

 paraphyses. Capsule — Erect and reddish when mature. Oper- 

 culum pale yellowish-green with a reddish base, incurved, and end- 

 ing in a long subula. Annulus none. Peristome of sixteen teeth, 

 deeply cloven, the teeth unequal in length, pale but reddish at the 

 base. 



The above description is from Hedwig ; that of Bruch and 

 Schimper somewhat diifers as follows : — Capsule striate, remotely 

 furrowed when dry, and sometimes curved. Annulus very narrow. 

 Male plants mixed with the female ones. 



The stems of D. flagellare often give off slender flagellse from 



