145 
ON SOME IRISH FORMS OF FISSIDENS. 
By H. N. Drxon, M.A., F.L.S. 
(PuateE 505.) 
(A.) FissIDENS EXSUL, sp. nov. 
THE genus Fissidens would almost seem to have a special 
affinity for the neighbourhood of Dublin. One of the most 
i ate 
species of Fissidens described by Lindberg (Rev. Bry. 1880, 
97) as Schistophyllum Orrii; but later on recognized by Mitten 
to be identical with his F’. tequendamensis from the Andes, de- 
Seagreees in the Musci Austro-Americani (in Journ. Linn. Soc. Bot. 
xii. 
Tow ards the close of 1909 Mr. D. McArdle sent me a small 
Pissidens from the Palm House in the Botanic Gardens, Glasnevin, 
iking r 
ces.- The generally tapering and acute leaves, the form and 
dimangins of the leaf-cells, and especially the form of capsule, 
s 
entirely free from et grain s. If this character stood 
alone, I should have been inclined to discount its value, and to 
suppose that the special conditions of growth—warmth, shade, 
wie abundant moisture—might be held to account for the- 
phyll wth. 
sae, The male flowers in F. tequendamensis are attached to 
the base of the fertile stem by rhizoids (¢.e. the inflorescence is 
rhizautoicous) ; in the plant under notice, while this form of inflores- 
urs, | have also found distinct male plants with terminal 
flowers, so that the inflorescence i is at times, at least, dioicou us. Itis, 
however, in the p figs sein 
was found. _ The basal part ; of the Peristome i in Fissidens 
show ne or both su otenue iitre all 
on fa: inner or ventral face. In most species of the genus their 
development is tes the normal character common to many mosses. 
In a small of exotic species, however o Pyenothallia 
ner 
and to a poeree searcely, I think, parélinion in i other kind of 
mos are described by Brotherus (Engler & Spay Pflan- 
soitaeesleen Huaei p. 355) as ‘kammfoérmig,’ 
y him, after Dusén, on the same page. The Glasnevin plent 
exhibits precisely this structure of peristome. Mr. Allen's 
(Plate 505, fig. 10) will perhaps give a clearer idea of the 
Jousaie or Borany.—Vou. 48. [Junz, 1910.] M 
