314 Mr. W. Mitten on the Mosses and Hepatica of Sussex. 



55. B. revoluta, Schw. 

 Tortula revoluta, Eng. Fl. 



Not unfrequent on walls. 



56. B. Hornschuchiana, Schultz ; " dioica ; laxe et late csespi- 

 tosa flavescens fragilis gracillima erecta parce breviter dichotoma ; 

 folia caulina sicca incumbentia, madefacta patentia, perfecte late 

 lanceolata acutissima, nervo crasso excurrente vel in superioribus 

 excedente, integerrima, inferiora minute sed dense areolata sub- 

 Isevia margine minus revoluto, superiora vel periehsetialia parum 

 majus areolata, margine erecto ; theca oblongo-cylindrica, badia 

 parva subcurvula, anguste annulata, operculo oblique subulato ; 

 perist. prsecedentis." [B. revoluta] C. Muller, Synops. p. 608. 



Probably not uncommon. At Aldrington near Brighton, growing 

 on the sandy soil between the road and the sea ; at Clayton on the 

 chalk ; on the Forest near Balcombe Tunnel ; and Mr. Borrer has 

 gathered it on Tunbridge Wells Common. 



Similar as this species is to B. revoluta in size and appearance, yet 

 when carefully compared, it presents many points of difference. The 

 stems are about half an inch high, green, or more frequently dirty yel- 

 lowish ; leaves patent, when dry appressed to the stem, and slightly 

 twisted, lanceolate, acute ; the nerve excurrent into a sharp point ; 

 the margins revolute ; the perichsetial leaves are broader below and 

 more subulate above, of a thinner and looser texture, and the margins 

 are not reflexed ; the capsules are subcylindrical ; the peristome re- 

 sembles that of B. revoluta. The plant does not form compact tufts 

 like B. revoluta, but grows in loose patches on the ground : the 

 leaves taper gradually to the point even when the margins are spread 

 out. In B. revoluta the leaves are obtuse mucronate, and when the 

 margins are spread out the point of the leaf is found to be broad 

 and rounded. The perichsetial leaves are six in both species : those 

 of B. Hornschuchiana are subulate from an ovate base, but those of 

 B. revoluta are broadly lanceolate and somewhat obtuse. 



The description of B. revoluta in ' Eng. Fl.' corresponds better 

 with B. Hornschuchiana than with the species intended, and it is 

 possible that the B. gracilis of English authors may belong in part 

 to B. Hornschuchiana. 



57. B. convoluta, Hedw. 

 Tortula convoluta, Sw. Eng. Fl. 



Frequent on chalky, gravelly, or sandy soils. 

 A variety with longer leaves, but always sterile, occurs on walls at 

 Hurstpierpoint. 



58. B. unguiculata, Hedw. 



Tortula unguiculata, Hook, and Tayl. Eng. Fl. 

 Common everywhere. 



59. B. fallax. Hedw. 

 Tortula fallax, Sw. Eng. Fl. 



Frequent, but not so ubiquitous as B. unguiculata. 



