l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 69 



RHACOMITRIUM DEFOLIATUM Dixon, sp. nov. 

 (Plate 1, fig. 4) 



Stirps praelonga, prolixa, caulibus 15 cm. aequantibus vel superanti- 

 bus, iter iterumque divisis, rigidiusculis, sacpc a basi usque fere ad 

 apice m denudatis, vel costis foliorum vetustorum solum praeditis. 

 Folia perrigida, sicca madidaque liorride crccto-patentia, plcrumque 

 rufo-aurantiaca, 2.5-3 mm - longa, e basi brevi ovata lanceolata, 

 sensim acutata, apice subacuta vel subobtusa, mutica, valde carinato- 

 concava, uno margine leniter recurvo ; costa valida, apud basin 70-95 

 p lata, plano-convexa, sectione (in medio folio) tres cellularum 

 series exhibens, quarum ventrales circa quattuor magnae, mediae 

 paucae (3-4) atque dorsales numerosae multo minores. Cellulae folii 

 basilares perangustae, alares bene cvolutae, magnac, subpellucidae, 

 superiores subquadratac,-isodianictricac, omnes sinuosae, 4-5 seriebus 

 marginalibus ab apice usque fere ad basin bistratosac, limbum bene 

 notatum incrassatum instruentes. Cetera nulla. 



Hab. : Loc. 3,630 meters, Nos. 1593 (type), 1339. Evidently more 

 or less submerged, or subject to aquatic action, probably in mountain 

 torrent or waterfall. 



A very distinct species, allied perhaps to R. protensum A. Br., but 

 very distinct in the color, smaller leaves, thickened margins, well- 

 developed auricles,, etc. Rhacomitriuiu alare (Broth.) Par. differs 

 entirely in the texture, weak nerve, elongate upper cells, etc. 



The leaf margin often appears papillose, through the erosion of 

 the outermost cell walls. 



RHACOMITRIUM ALARE (Broth.) Par. 



Loc. 3,630 meters, No. 1555, c. fr. The fruiting plant has not, I 

 believe, been recorded. The sporophytic characters are of some 

 interest, the two innermost perichaetial leaves being wide, very 

 obtuse, and convolute, so as to form a tubular sheath around the 

 base of the seta; the seta is yellow (brown when old), 1 cm. long; 

 capsule elliptic-cylindric, castaneous when old. Peristome not seen. 



The leaf apex varies greatly, being nearly always obtuse and 

 quite hairless, while other leaves on the same stem will be acute with 

 a short piliform hyaline point. 



RHACOMITRIUM DURUM (C. M.) Par. 



Loc. 3,630 meters, No. 1556, c. fr. This species also, I believe, has 

 not been recorded hitherto in fruit. It was originally described from 

 the Cameroons, but is recorded by Brotherus (1) from Central 



