Amertran 3ta Journal 



Vol.4 JULY— SEPTEMBER, 1914 No. 3 



• 



Some new American species of Dryopteris 



CARL CHRISTENSEN 



Since the publication of the first part of my mono- 

 graph of the genus Dryopteris just a year ago I have 

 examined a number of specimens collected recently in 

 tropical America, some of which are found to belong to 

 species hitherto undescribed. The present article con- 

 tains descriptions of these and is thus a first year's sup- 

 plement to the first part of the monograph. There is 

 included also mention of two older species with which 

 I was unacquainted before. 



Dryopteris (Lastrea) Shaferi Maxon & C. Chr., sp. nov. 



Rhizome erect, 2-3 cm. high. 1 cm. thick, with many 

 branched roots, furnished at the top with few brown, 

 rather rigid, small (2-4 mm. Ion-) scales, these cihate 



by short, subulate, simple hairs. Stipites fasciculate, 



many together, rather strong and rigid, 4-6 cm. long, 

 sulcate and very shortly pubescent above, rounded and 



nearly glabrous beneath, without scales. Lamina linear- 

 lanceolate, 20-30 cm. long. 4-6 cm. broad at the middle, 

 coriaceous, grayish green, short-acuminate, gradually 

 tapering downward through 4-6 pairs of very reduced, 

 auriculiform pinnae, pinnate-Bubbipinnatifid. Kaclus 

 very shortly pubescent by simple, spreading, acute 

 hairs. Pinnae numerous (in larger fronds 30-40-jUg- 

 ate), sessile, alternate or subopposite, spreading, linear 

 generally more or less falcate, about 4 cm. long, o 



[No. 2 of the JorRNM. (4: 41-76) was issue:! Juno 9. ltt«J 



77 



