TORTULACE^E.] 205 [Tortula. 



Autoicous ; gregarious or csespitulose, gemmiform, stramineous or 

 silvery ; stem simple or innovating. Leaves imbricated, glossy, broadly 

 obovate, lower obtuse, upper apiculate, very concave, margin incurved, 

 nerve vanishing below apex ; cells at base rectangular, above small, 

 rhombic, incrassate. Perich. bracts elongated, narrowed, seta longish, 

 orange, caps, oval-oblong, annulate, glossy castaneous, lid obliquely 

 rostrate ; teeth lanceolate, entire or cleft to middle, pale or reddish. 

 Male infl. gemmiform, bracts three, oval. 



HAS. Crevices of rocks ; very rare. Fr. 5 6. 



Glen Phee, Clova (Drummond 1824) ! ! Carr rocks above Castleton (Dickie 1867) ! ! 



Differing so much in habit from the other species that I have felt tempted 

 to follow Venturi and regard this as the type of a distinct genus, but the 

 similarity in the capsule and peristome to those of Pottia has inclined me to 

 retain it here. According to specimens in Dickson's and Smith's herbaria, 

 Bryum piliferum DICKS. Crypt, fasc. IV, 10, t. 10, fig. 14. belongs to 

 Tortnla (Desmatodon) systylia (BR. SCHIMP.) a rare species found at great altitudes 

 in Norway, and most unlikely ever to have been found at Aberfeldy ; P. latifolia 

 var. ft. pilifera (Dicramim bullatum SOMM.) must therefore be excluded from our 

 lists as well as Tortula (Desmatodon} latifolia (HEDW.). 



5. TORTULA HEDW. 



(Fund. muse. II, 92 (1782). ) 



Plants short or tall, caespitose, simple or dichotomously branched, 

 yellowish-green. Leaves oblong or spathulate, papillose, usually obtuse 

 with the nerve excurrent or extended into a long pellucid hair ; areola- 

 tion hyaline and elongated at base, quadrato-hexag. opake and chloro- 

 phyllose above ; perich. bracts scarcely diverse. Cal. cucullate. Caps, 

 erect, oblong or cylindraceous, subincurved, sometimes gymnostomous, 

 teeth of peristome 32, filiform, carinate, papillose, remotely jointed, 

 placed on a distinct tubular, more or less elongated basal membrane, 

 straight, incurved or spirally contorted. Spores small, nearly smooth. 

 Inhabiting the ground, walls, or rocks, rarely trees. Der. tortus 

 twisted. 



The genera Tortula and Barbula were founded by Hedwig in his Fund, 

 muscorum, but he gives no other distinction than that Tortula has mon- 

 oicous infl. (ex. T. muralis and subulata), and Barbtila dioicous (ex. B. 

 rurnlis and unguiculata}. This character is, of course, insufficient to 

 separate genera, and Schreber amended it by uniting the two, and 

 naming it Tortula, in which he has been followed by most English 

 authors, while the continental writers sink Tortula and use that of Bar- 

 bula. By bringing into greater prominence the colour and structure of 

 the leaves, we obtain two series, which may conveniently be retained as 



