New and Interesting South African Mosses. 
219 
distributed as I. hrachycarjmm. I have therefore retained that name. Both 
on account of the scarcely enlarged, not decurrent basal cells (except for the 
small group of two or three hyaline ones), and on account of the undoubted 
affinity with I. Dnhyi, I. WelwitscJiii, I. strangulatum, etc., I think it must 
be placed in Isopterygium. 
It resembles Flag, rhyrichostegioides C, M., but is a much smaller plant 
altogether in all its parts. I. WelwitscJiii Grepp resembles it, but apart from 
the perichaetial leaves has more gradually tapering, longer leaf-points, a 
longer seta, etc. 1. Antunesii Broth, is larger, with sharply denticulate leaf- 
points, and a different capsule, I. Dnhyi G-epp has the same character of 
perichaetial bracts, but is a far more robust plant, larger in all its parts, with 
much wider leaf -cells. 
I. strangulatum Hampe also resembles it, but is larger, and has wider 
areolation, and is without the enlarged alar cells. 
Plagiothecium Hendersonii Dixon, sp. nov. (PL XII, fig. 20.) 
Sat rohustum, jpraeriitens, laetevirens ; caulis repens, irregulariter ramosus, 
ramis brevibus, foliis complanato-decurvis. Folia l"5-2 mm, longa, late 
oblongo-lanceolata, breviter late acuminata, concava, apice subdenticulato, 
marginibus erectis, basi subdecurrentia ; costa gemella, brevissima vel 
nulla; cellulae angustae, 5-7 fx latae, elongatae, valde prosenchymaticae, 
parietibus angustis, firmis, basin versus sensim latiores, infimae 10-13 /x 
latae, parietibus incrassatis, porosis ; alares numerosae, magnae, regulariter 
suhquadratae, perpellucidae. 
Autoicum, Perichaetia circa 3 mm. longa, foliis externis subsquarrosis, 
internis suberectis, omnibus in acumen longum subulatum integrum vel 
subintegrum productis. Cetera ignota. 
jffa?^.— Hogsback, Tjumie, CP., alt. 4-6000 ft., 1917 ; coll, D Henderson 
(Nos. 366, 365). 
Only young setae were found. A quite distinct species, with habit 
perhaps most nearly that of P. denticidatum (L.), but with much narrower 
upper areolation, and very numerous, subquadrate alar cells. P, rhyncho- 
stegioides C. M. differs in the smaller size, the finely acuminate points of the 
leaves, the basal cells little enlarged, the perichaetial leaves with very long 
capillary subula. P. selaginelloides C, M, and P, memhranosulmnC M. have 
laxer, quite different areolation. 
Catagonium mucronatum (C. M.) Broth. George, CP., 1916 ; coll. 
H. A. W. (Nos. 502, 503), c. fr. ; near Hogsback, Tjumie, 4-6000 ft., 1916 ; 
coll. Hend. (No. 201a). 
Vesicularia sphaerocarjja (C M.) Broth. Barberton, Transvaal, 1914 ; 
coll. H. A. W. (Nos. 256, 259), c. fr. ; Mossel E., CP., 1913 ; coll. Prof. C. 
Potts, comm. Sim (No. 24) ; Pinetown, New Germany, 1000 ft., Natal, 
1917; coll. P. van der Bijl, comm. Sim (No. 8680), c. fr. ; Knysna, CP., 
1700 ft., coll. J. Burtt-Davy, comm. Sim (No. 8679). Mr. Sim writes 
