ToRTULACE^.] 229 [Mollia. 



with an adherent lid, or gymnostomous, the mouth being sometimes 

 closed by a membrane, or with a peristome consisting of a narrow 

 basal membrane supporting 16 teeth, more or less developed, papillose, 

 cleft to base into two equal or irregular legs, straight or occasionally 

 contorted. Inhabiting the ground, walls or rocks. — Der. after K. E. 

 von Moll, Archbishop of Salzburg, author of " Naturhist. Briefe ueber 

 Salzburg" (1785). 



The genus Mollia, founded by Schrank as an equivalent to Torttila or 

 Barhula, ma}' well be retained for this group, as Trichostomum was established 

 by Hedwig in 1782, for the section of Grimmia named Rhacomitrium and some 

 species of Ditrichum, and it was not until more than 20 years after this 

 that any of the species now referred to Trichostomum were brought into it. 



Taken as a whole, we must look upon the genus Mollia as an eminently 

 natural one, ascending from several little phascoid mosses, through a series 

 of closely allied forms, to the taller species culminating in M. toriuosa, all 

 marked by their narrow opake papillose leaves, curled or twisted when dry, 

 and a peristome of one common type, presenting various stages of develop- 

 ment. A little study of the species will soon convince the student that 

 Systegitmi, Weissia, Gymnostomum, Didymodon, Hymenostomum, Eucladium, Gyro- 

 weissia, Leptobarhila have no sound basis as genera, but may be readily 

 distributed in the three sections adopted. 



Hymenostomum stands to Mollia almost exactly in the same relation as 

 Pottia does to Tortula, and we see in the species it includes, only miniatures 

 of the larger forms of the third section, and just as closely allied to each other 

 as certain Pottias axe. 



In Tortella a very important character may be noticed in the relation of the 

 two kinds of cells composing the leaf base, in some species the white thin 

 elongated hyaline cells meet the small chlorophyllose cells at the same level 

 from nerve to margin, in others at a certain height, the hyaline cells leave the 

 nerve and ascend obliquely outward to the margin, so that the demarcation 

 between the two is very distinct. 



Besides the continental species incidentally referred to in the text, 

 the second edition of Schimper's Synopsis contains a number of others, 

 both in this genus and the last, which it may be useful to enumerate, as atten- 

 tion is thus drawn to them, though except Tortula cenma and inermis, it is not 

 probable that any of them will be met with here. 



Under Tortula in the section Desmatodon, we find T. squamigera (Viv.), 

 B. membranifolia Schultz, — T. crassinervis De Not., B. chloronotos B. & S. — 

 Guepini B. & S. — anomala (B. & S.) — barbuloides (Brid.) — flexiseta (Bruch.) — 

 systyUa (B. & S.) — latifolia (Hedw.) — cernua (Hueben.), — limbata (Lindb.) — 

 obibisifolia Schleich. D. flavicans (B. & S.), — Solmsii Schimp. the last three 

 n^r T. mavginata; in Zygotrichia, T. Laiireri (Schultz) and T. suberecta 

 HoSk., D. obliquus B. & S. and in Syntrichia, T. alpina (B. & S.) 



Under Mollia in Sect. Hymenostomum, we have M. muralis (Spruce). — 



crispata (Nees Hornsch.), — Wimmeri (Sendtn.), — Welwitschii (Schimp.), — 



'triumphans (De Not), — Monspeliense (Schimp.) — berica (De Not.), — meridionalis 



and Winteri (Schimp.) ; in Eucladium, M. reflexa (Brid.) near tenuis, — Piiiliberti 



