D1TRICHUM. 59 



Var. /3. zonatum Lindb. (Weisia zonata Funck). Stems 

 elongated, slightly branched, in dense tufts, bright green above, 

 brown below ; \-2 inches high. Leaves shorter, appressed when 

 dry. 



Hab. Sandy banks and crevices of subalpine rocks, frequent. The var. j8 on 

 mountain rocks, more rare. Fr. autumn. 



The commonest of the short-stemmed species, and usually fruiting, except in the 

 case of the var. zonatum, which is always barren. The narrow areolation of the 

 leaves is perhaps the most obvious distinguishing character, and also the dark-coloured 

 capsule. From the next species it differs essentially in the inflorescence. The peris- 

 tome, as is usual in this genus, is very fragile. 



The var. zonatum has been variously located, and has recently been raised again 

 to the rank of a species by Limpricht, but in the absence of fruit its relationship with 

 the present species appears too great to permit of separation ; the elongated, closely- 

 tufted stems, however, give it a totally distinct aspect in the field. 



4- Ditrichum subulatum Hampe (Trichostomum subulatum 



Bruch ; Leptotrichum subulatum Hampe., Schp. Syn.) 



(Tab. XII. K.). 



Plants short, slender, in loose, silky, bright yellowish green 

 tufts. Leaves flexuose when dry, the lower small, ovate-lanceo- 

 late, the upper from a short oval base abruptly narrowed to a 

 long, flexuose, setaceous, almost entire subula, the greater part of it 

 composed of the broad, excurrent nerve. Margin plane. Cells 

 rather laxer, broader and shorter than in the last species. Peri- 

 chaetial bracts sheathing. Seta slender ; capsule erect, golden 

 brown, ovate, wider than in the last species, broadest near the 

 base ; annulus almostf obsolete ; lid shortly rostellate. Peristome 

 teeth very slender, divisions slightly coherent ; basal membrane 

 very short. Paroicous ; antheridia naked, in the axils of the 

 upper leaves immediately below the perichaetial bracts. 



Hab. On crumbling rocks and clay soil ; very rare. Cornwall ; Devon, Fr. 

 spring. 



A Mediterranean species which has reached our southern coast. Clearly dis- 

 tinguished by its paroicous inflorescence, and the bright green flexuose leaves, with 

 nerve longly excurrent. 



5. Ditrichum flexicaule Hampe (Didymodon flexicaulis 



Schleich. ; Leptotrichum flexicaule Hampe., Schp. Syn.) 



(Tab. XIII. A). 



Tall, slender, in close soft silky tufts, yellowish or brownish 

 green, glossy ; stems 7-5 inches high, very slender, flexuose, 

 fragile, branched, radiculose. Leaves very long, rather loosely 

 set, erect or secund, occasionally falcato-secund, slightly flexuose 



