24 



lOl. PSIL.OTXJJM, Swartn. 



Sporangia globoso-triangular, 3-locular, 3-lobed, much larger than the 

 sporophylla. 



Stems flattened or angular, mostly copiously dichotomous in the 

 upper half; trachei'de bundles united in a single, irregularly stellate, 

 3 — 10-radiate group. Leaves minute, rather rudimentary, sessile, remote, 

 triangular, arranged in 2 — 3 rows; sporophylla as large as the barren 

 leaves, sessile, adnate, deeply and acutely 2-lobate-dentate, arranged all 

 dovim the branches. — Engl. & Prantl, Nat. Ffl.Fam., l\ fig. 382, 383 A. 



Chiefly tropical and subtropical. 



• Stem and branches flattened; leaves in 2 rows. (1) Ps. complanatum. 

 •• Stem and branches triquetrous; leaves in 3 rows. (2) Ps. triquetrum. 



(1) Ps. complaiiatum, Sw., Syn., 188, 414, tab. lY, fig. 5; 

 Bk., Fern All., 30; Schk., Krypt. Gew., I, tab. 165 b; Ps. Zollingeri, Ces., 

 Fel. di Bor., 36; — var. flaccidum; Ps. flaccidum, Wall. 



"Whole plant about 15—60 cm. long, pendulous, laxly branched, the 

 ultimate branchlets flat, 2 — 4 mm. broad, and the leaves and sporangia 

 arranged distichously. 



'Var. flaccidum: Branchlets broader. 



Tropical and subtropical. 



(2) Ps. triquetriiin, »«., Syn., 117; Bk., Fern AIL, 30; Schk., 

 Krypt. Gew., I, tab. 165 b; Bau. & Hk., Gen. FiL, tab. LXXXVII; Hk., 

 Fil. Exot., tab. LXIII; — var. capillare; Ps. capillare, Bl. 



Whole plant about 15 — 60 cm. long, erect or nutant, many times di- 

 chotomously forked; branches triquetrous, the ultimate branchlets Vz — I'A 

 mm. thick, and the leaves and sporangia placed on the angles of the 

 branches. 



Var. capillare: Branchlets fine, indistinctly triquetrous. 



Tropical and extra-tropical. 



