316 BRYOPHYTA OF S. RHODESIA. 



differt foliis e basi brevi dilatata, obo'vata, cito in laminam anguste 

 lingulatam, obtuser acutam contraetis, cellulisque distinctis, per- 

 chlorophyllosis, majusculis, 10/u, ad 12/x latis, basilaribus sensim 

 elongatis, rectangularibus, infimis juxtacostalibus elongatis, lineari- 

 bus, teneris, pellucidis. Costa valida, ad basin 70/x ad 90/x lata, 

 subpercurrens. Folii margines erecti, integri vel apice obsolete 

 sinuosi, nullo modo incrassati. Seta perbrevis, 3 mm. longa, theca 

 parva, turgide elliptica, collo sat distincta, operculo plus minusve 

 breviter rostrato. 



Habitat: Matopos, alt. 5,000 feet (Sim, 8851); Zimbabwe, 

 alt. 3,000 feet (Sim, 8808); on granite rocks, Macheke, alt. 5,000 

 feet (Eyles, 1994). 



Quite distinct in the rather large, not obscure, chlorophyllose 

 cells, the dilated base of the leaves, wider above and obovate or 

 suborbicular, the very short seta. 



It may be of help to give here a tentative key to the South 

 African species of Ptvchomitrium.* 

 1 



Leaf margin at least in some parts bistratose 2 



Margin unistratose 3 



2 



Setae 3 mm. to 5 mm., frequently in pairs; deoperculate 



capsule about 1 mm. long 



subcrispatum Ther and P. de la Varde. 



Seta 5 mm. to 10 mm., single, capsule about 2 mm 



marginatum (Wager and Dixon). 



3 



Leaves distinctly cucullate at apex, seta very short 



cucullatifolium (CM.). 



Leaves not or not markedly cucullate 4 



4 



Upper cells minute, opaque, leaves not markedly widened 



at base 6 



Upper cells larger, distinct 5 



5 



Base not markedly widened crassinervium (Schimp.) 



Base markedly widened eerybasis (Dixon). 



6 



Basal margin widely recurved depressum (CM.) 



Margin erect or nearly so 7 



7 



Leaves strongly crispo-circinate when dry 



crispatum (Hook and Grev.). 

 Leaves scarcely crisped when dryf obtusatum (CM.). 



* P. mucronatum Schimp. e C. M. in "Hedwig," 38. 122, does not belong 

 to this genus. Original specimens in herb. Schimper at Kew show 

 it to be a Trichostomum or allied genus. 



t 1 take this from C. Mueller's description ; T have seen no specimens. 

 It appears e clescr. to differ little from P. crispatum. 



