the top tapering shortly into the stout beak which is 1 mm. long and about 0.4 

 mm. thick. 



In wet meadows and wet soils in ravines, in Okla. (Washita Co.) and very 

 rare if not extinct in the Davis Mts. in the Tex. Trans-Pecos, N.M. (widespread) 

 and Ariz. (Apache. Navajo, Coconino and Cochise cos.); widespread in Rocky 

 Mts. and s. to Mex. and Guat.; also Mich., Wise, la., Mo. and Que. to Alas. 



5. Lactuca floridana (L.) Gaertn. 



Robust annual (5-) 10-25 (-33) dm. tall, the stem simple for nearly the entire 

 height or branched only very near the top; leaves nearly all deeply runcinate- 

 pinnatifid but with an extremely ample triangular terminal portion and only 1 

 (or 2) large lateral lobes on each side, marginally toothed; involucres 9-10 mm. 

 long at anthesis, to 10-12 mm. long in fruit; corollas bluish or white; achene 

 body oblanceolate, 4-4.5 mm. long, flattened but not at all winged, about 3 times 

 as long as broad, with 2 or 3 longitudinal nerves on each face and many weak 

 transverse internerve ridges, mottled black and brownish-gray, shortly tapered 

 apically to a stout somewhat beaklike cylindrical apex (0-) 0.5-1 mm. long and 

 0.5 mm. thick. L. villosa Jacq. 



Along streams, in wet thickets and alluvial woods, swampy ground and in wet 

 sands in e. Okla. (Waterfall) and in n.-cen. and e. Tex., rare to s.e. Tex., 

 Aug.-Oct.; e. U.S. 



50. Crepis L. Hawk's-beard 

 A genus of perhaps 200 species of the Northern Hemisphere and Asia. 

 1. Crepis runcinata (James) T. & G. 



Essentially glabrous perennial from woody or slightly fleshy rootstocks to 

 5-10 mm. thick, these apparently branched well-underground; leaves all crowded 

 at the base, 5-12 cm. long, 15-30 mm. broad, oblanceolate, nearly entire or rarely 

 with a few teeth or shallow lobes, rather fleshy and glaucous, essentially sessile; 

 cauline leaves only 1 or 2 per stem and much-reduced to mere bracts, entire and 

 oblanceolate, appressed; scapelike stems sparingly branched, the branches ascend- 

 ing with each terminating in a head; heads few; involucre narrowly campanulate, 

 12-20 mm. long, an inner double series of subequal linear-subulate thin-mem- 

 branous scarious-margined phyllaries and 8 to 10 much shorter calyculate ones at 

 the base; receptacle convex, naked or with a few minute hairs; rays yellow, 

 5-toothed terminally; achenes 4-5.5 mm. long, slightly attenuate apically but not 

 beaked, nearly columnar or the outer ones somewhat compressed, with 10 to 13 

 ribs; pappus rather persistent, of a number of white fine capillary bristles which 

 are lightly coherent basally. C. perplexans Rydb. 



Rare in open seasonally moist prairies and about playa lakes in the higher 

 parts of Tex. Plains Country (Dallam Co.), and N.M. (eastern half), summer; 

 very widespread in Great Plains and trans-Montane basins. 



51. Taraxacum Zinn Dandelion 

 A Temperate Zone genus of perhaps 50 species. Hundreds of species have 

 been proposed, based largely on apomictic populations. 



1. Taraxacum officinale Wiggers. Common dandelion. Fig. 784. 



Winter annual or perennial herb from deep taproots to 1 cm. thick; leaves all 

 crowded in a basal rosette, 5-15 cm. long, runcinatcly pinnatifid; stems scapose, 

 3-20 cm. tall, solitary or few, each topped by a solitary head; involucre broadly 

 obconic, 1-2 cm. broad and high; phyllaries in 2 definite size-classes; inner 

 (longer) phyllaries in 2 equal series, linear-subulate, thin-membranous with 

 hyaline margins, at anthesis appearing very slightly coherent at the overlapping 

 margins but with age pulling apart and eventually spreading at maturity of fruit, 



1703 



