262 Broadhurst: Struthiopteris in North America 



Rhizome scales never with a black median line; lamina 

 broadly lanceolate to lanceolate, 2.5-4.5 times as 

 long as broad, usually abruptly reduced below (type 

 D to E, with vestigial pinnae); leaf tissue mem- 

 branous to herbaceous; pinnae distant in the basal 

 half to third of the lamina. 6. 5. Plumieri. 



Plants terrestrial; rhizome inclined to erect; rhizome scales and 

 basal stipe scales never with a black median line; stipes 

 clustered at the apex of the rhizome, the fertile ones 

 partly, or oftener wholly, shining chestnut to black; 

 mature lamina fully punctate by transmitted light (see 

 5. Spicant for exceptions); fertile pinnae conspicuously 

 dilated at their bases (except in S. Maxonii). 

 Sterile lamina gradually reduced at the base (type F-G, 

 without vestigial pinnae); vein spaces 8-15 to 1 cm. 

 Rhizome erect (43 cm. high, in type); vein spaces 8-10 



to I cm.; fertile pinnae not dilated at their bases. 5. .S. Maxonii. 

 Rhizome creeping or stoloniferous; vein spaces 10-15 

 to 1 cm.; fertile pinnae conspicuously dilated at 

 their bases. 

 Sterile fronds of two types in texture and position, 

 20-70 cm. long; rhizome apparently not stolonif- 

 erous; pinnae 36-80-jugate, 3-15 times as long 

 as wide. 8. S. Spicant, 



Sterile fronds similar in texture at least, 11-20 cm. 

 long; rhizome stoloniferous; pinnae 16-22-jugate, 

 1-3 times as long as wide. 9. 5. stolonifera. 



Sterile lamina abruptly reduced at the base (type B-D, 

 with vestigial pinnae except in S. L'Herminieri)\ 

 vein spaces 6-8 to 1 cm. 

 Stipes (of the sterile fronds, at least) without scarlike 

 vestigial pinnae; lamina lanceolate, 5-1 1 cm. wide; 



pinnae mainly falcate, ascending. 4. 5. L'Herminieri. 



Stipes with vestigial pinnae; lamina elliptical, ovate- 

 lanceolate, oblong-deltoid, or deltoid, 12-32 cm. 

 wide; pinnae mainly straight, diverging. 

 Lamina of mature fronds deltoid to oblong-deltoid, 

 or ovate-lanceolate and very abruptly reduced 

 below (type A or B); lower pinnae contiguous, 

 if shorter abruptly reduced to semicircular lobes; 

 sporophyls fertile on the dilated bases of the 

 pinnae. 2. S. exaltata. 



Lamina of mature fronds broadly elliptical, less 

 abruptly reduced below (type D) ; lower pinnae 

 distant or appearing so, always shorter; sporo- 

 phyls not fertile on the dilated bases of the 

 pinnae. 3. S. jamaicensis. 



I. S. ensiformis (Liebm.) Broadh.; Maxon, Contr. U. S. Nat. 

 Herb. 13: 17. 1909. 



