﻿224 Maxon: Pdlypodium marginellum and its allies 



abruptly attenuate in the apical part (the extreme apex sub- 

 caudate), the margins delicately repand, appearing undulate in 

 drying, bordered by a delicate filiform line of lustrous blackish- 

 brown sclerotic tissue, this bearing a few minute caducous branched 

 glandular hairs, similar hairs extending sparingly to the leaf 

 tissue; veins free, arising at an angle of about 35°, slender, con- 

 cealed, but their course easily evident, the sterile ones simple; sori 

 oval, extending from below the apex to the middle of the lamina, 

 seated partially or sometimes wholly upon a very short divergent 

 translucent distal spur of the vein, far below its middle, thus 

 borne close to the concealed but sharply elevated slender costa, 

 separate or at maturity subconfluent. Leaf tissue firmly mem- 

 brano-chartaceous, dark green, paler beneath, the veins, easily 

 evident without transmitted light. 



Type in the U. S. National Herbarium, no. 694419, collected 

 from mossy trunks of forest trees, Sierra de Naguabo, eastern 

 Porto Rico, March 8, 1914, by Mr. W. E. Hess (no. 312). Mr. 

 J. A. Shafer's no. 2328, collected at the same time and place, is 

 identical. Other specimens studied, all from Porto Rico, are as 

 follows: Hioram2i2)A'^Blauner2'j2; Sintenis lygi ; 5^a/er 3320, 3516, 

 3660. 



Polypodiiim Hessii is closely related to P. limhatum of the 

 . Lesser Antilles, but differs sufficiently in its more rigid and darker 

 rhizome scales, in its nearly basal sori, and in its distinctly stipitate 

 (rather than nearly or quite exstipitate), 

 fronds. The marginal band of sclerotic tiss 

 delicate and threadlike, as opposed to the glistening, broadish, 

 almost flat sclerotic band of P. limhatum. P. Hessii is not likely 

 to be mistaken for the widespread P. nigrolimhatum, with which it 

 is contrasted in the preceding key. 



6. Polypodium ebeninum Maxon, sp. nov. 

 Plants apparently epiphytic; fronds numerous, 5-10 cm. long, 

 ascending, imbricate-fasciculate in a small crown. Rhizome erect 

 or ascending, 7-10 mm. long, 1-1.5 mm. in diameter, paleaceous, 

 the apical portion partially concealed; scales acicular, 2-2.3 ^^ni. 

 long, 0.17-0.25 mm. broad, subflexuous toward the slender gland- 

 tipped apex, rich castaneous from a yellowish brown base; stipe 

 proper nearly wanting, alate, passing gradually into the narrow 

 lamina from a brownish base; lamina 5-9 cm. long, 2-4 mm. 

 broad, straight or slightly arcuate, narrowly linear, acutish or 

 obtuse, broadest in the apical third, thence very gradually long- 

 'le base, entire, slightly repand, the margin consisting 



