NO. 24 REMARKAI5LE NEW FERN FROM PANAMA — MAXON 3 



brown base, or discolored throughout, I to 6 cm. long or nearly 

 wanting, flattened, very narrowly alate above (gradually passing 

 into the narrowly winged rachis), rather densely pilose with very 

 slender, fragile, spreading, rufous hairs 2 to 3.5 mm. long; lamina 20 

 to 50 cm. long, of varying form and indeterminate growth, readily 

 abortive at the apex, the pinnae simple and usually elongate, or 

 greatly extended and freely branched near or beyond their middle, 

 the numerous slender liranches commonly forming a subdichotomy; 

 pinnae spreading or slightly ascending, adnate, joined uniformly by 

 a narrow wing about 1 mm. broad, decurrent, the simple ones linear- 

 caudate, 4 to 14 cm. long, 3 to 5 mm. broad and entire if sterile, if 

 fertile distantly and obliquely serrate-pectinate to dentate, 5 to 9 

 mm. broad including the teeth or lobes, these i to 3 mm. long, 

 rounded and soriferous at the apex ; veins free, very oblique, the 

 sterile ones i- to 3-forked, the fertile ones forked, the sorus borne at 

 the clavate apex of the greatly elongated anterior branch, very 

 close to the margin ; sori large, hemispherical, or by their position 

 nearly globose, the sporangia arising from the lower surface but 

 crowding outward in the plane of the lamina, the sorus thus appear- 

 ing nearly or quite terminal upon the lobe ; leaf tissue of young 

 plants firmly membrano-herbaceous, the veins apparent by trans- 

 mitted light, of mature plants thicker and spongiose, the veins seen 

 with difficulty ; both surfaces of the lamina (including the green- 

 ish rachis and nearly concealed midveins) covered throughout with 

 short, distant, dark, gland-like hairs. 



Type in the U. S. National Herbarium, no. 676092, collected 

 from a tree trunk in the humid forest of the upper Caldera water 

 shed, between " Camp I " and the Divide, Holcomb's trail, above 

 El Boquete, province of Chiriqui, Panama, altitude 1,750 to 1,925 

 meters, March 23, 191 1, by William R. Maxon (no. 5640). 



The specimen designated as the type is but one of several mounted 

 plants (numbers 5640 and 5656) showing the extremes of leaf form 

 within the species. It is shown at exactly one-half natural size in 

 Plate I and may be taken to indicate the "normal" form of the 

 mature frond. Plate 2 represents at the same scale a plant of no. 

 5656 in which the tendency toward repeated dichotomy of the pinnae 

 has found ample expression. Plate 3. at about two-fifths nat- 

 ural size, shows a plant of no. 5640 approaching maturity and 

 possessing an unusually large number of fronds, most of which have 

 escaped injury at the apex while young and have in consequence 

 attained a fair length. 



