Studies in North American Polygonaceae 



/ 



John Kunkel Small 



Eriogonum xanthum sp. nov. 



Perennial (section Flavd), dwarf, closely pale-pubescent. Stems 

 (caudices) closely tufted, densely leafy, the lower portions densely 

 clothed with the persistent leaf-bases : leaves numerous, crowded ; 

 blades spatulate, 1-2.5 cm - l° n g> obtuse, somewhat floccose and 

 greenish above, more closely pubescent and gray beneath, rather 

 slender-petioled : scapes 3-5 cm. tall, simple, pubescent, like the 

 upper surface of the leaf-blades : bracts spatulate, quite similar to 

 the leaves, but usually 1 — 1 . 5 cm. long: involucres nearly sessile, 

 capitate, turbinate, ultimately ribbed, about 4 mm. long ; lobes 

 triangular, about one fourth as long as the tube : calyxes yellow, 

 becoming 8 mm. long, including the stipe-like base, which is about 

 1.5 mm. long, silky-pubescent without; lobes spatulate or the 

 outer ones pandurate-spatulate : filaments copiously villous below 

 the middle : ovary sparingly pubescent at the top ; styles sparingly 

 pubescent at the base : achenes about 5.5 mm. long. 



Collected on Mt. Harvard, Colorado, August 17, 1896, by 

 C. L. Shear, no. jySp (type), and on Gray's Peak, Colorado, 

 August, 1873, by Mr. Woolson. 



Related to both Eriogonum flavum and E. auraim, but differ- 

 ing from both of them in its longer slender base of the perianth and 

 the glabrous, persistent leaf-bases. 



* Eriogonum umbelliferum sp. nov. 



Perennial, with woody branching rootstocks (section Umbel- 

 lata) y bright-green. Stems represented by short caudices : leaves 

 crowded on the caudices ; blades spatulate to elliptic or oval, 1-4 

 cm. long, or rarely longer, glabrous or nearly so at maturity, ex- 

 cept the floccose-ciliate margins, slender-petioled: scapes 6-28 

 cm. tall, each topped with a 2-6-rayed umbel, which is subtended 

 by a whorl of foliaceous bracts: peduncles mainly 1-2 cm. long 

 and closely pubescent during anthesis, larger and thinly pubes- 

 cent at maturity : involucres campanulate, sometimes becoming 

 turbinate-campanulate, 2-2.5 mm. long, the lobes fully as long as 

 the tube and strongly reflexed : calyxes yellow or sometimes red- 

 tinged in age, about 8 mm. long at maturity, including the stipe- 



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