The Ditrichum Mosses 



Ditrichum pallidum. (a) cells 

 from annulus ; (fc) annulus , (c) 

 portion of peristome. 



Genus DITRICHUM, Timm, (1788) 



LEPTOTRICHUM, Hampe, (1842) 



The species of this genus are smooth and glossy plants 

 growing in pale yellow-green tufts on soil or on rocks. The 



plants are dwarf, or tall and slender 

 with lance-shaped, long- pointed 

 leaves, and oval or cylindrical, erect 

 spore-cases on long and straight, 

 rarely flexuous, pedicels. 



The peristome has a compound 

 annulus, and a single row of purple 

 teeth cleft to the base into two slender, 

 cross-barred segments, which have 

 suggested the name of the genus. 



The generic name Leptotricbum, 

 used by some for the genus, from 

 XeTTTo?, narrow, and 6pl%, rpt^o?, a 

 hair, has been shown by Hampe to be 

 untenable, having previously been 

 given to a genus of fungi. It has been 

 replaced by Ditrichum, from &<?, two, and dpl^, r^o?, a hair. 

 This name has also the right of priority, 



There are seventy-two species in all, seventeen in North 

 America. 



Ditrichum pallidum, Leptotricbum pallidum, Hampe, 1. c. 

 See Colour Plate XIV. 



Habit and habitat. Common in loose tufts, pale or yellow- 

 green, on bare sandy or clay-soil, in fields or by roadsides. 



Name. The specific name pallidum, pale, refers to the colour. 

 Plant (gametopbyte) . Slender, erect. 



Leaves. Open, erect, spreading or curved to one side, lance- 

 shaped at base and prolonged to an awl-shaped apex ; vein 

 extending beyond the apex and distinctly toothed. 



Habit of flowering. Male and female flowers on the same plant 

 (monoicous) ; the male flower-clusters bud-like at the apex of 

 the stem. 



Veil (calyptra). Split up one side. 

 Spore-case. Long, egg-shaped, brown. 

 Pedicel. Bright yellow, i to 2 inches long. 

 Lid (operculum). Conical, short-beaked. 



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