peduncles 4-12 cm. long; involucre of filiform mostly entire bracts much shorter 

 than the rays; involucel of filiform entire bractlets shorter than the pedicels; rays 

 25 to 30, spreading, subequal, 15-35 mm. long; pedicels 25 to 30, spreading, 

 3-8 mm. long; calyx teeth conspicuous, linear-lanceolate, persistent; styles 0.5-1.5 

 mm. long, strongly recurved; fruit ovoid, 1-1.5 mm long, 1 mm. broad, the lateral 

 ribs inconspicuous, only slightly corky-thickened. 



In moist sandy soil, in wet prairies and other moist places in Okla. (widespread) 

 and in the e. half of Tex., Apr.-July; from 111., s. to La. and w. to Kan. and Tex. 



21. Cynosciadium DC. 



A monotypic genus. 



1. Cynosciadium digitatum DC. Fig. 592. 



Plant slender, erect, caulescent, herbaceous, annual, 15 cm. high, dichotomously 

 branching in the inflorescence, from a fascicle of fibrous roots; basal leaves linear- 

 lanceolate, tapering at base, acute at apex, entire and septate, to 12 cm. long and 

 5 mm. wide; cauline leaves 3 to 5, palmately parted with narrow elongate divisions; 

 inflorescence of compound umbels, the peduncles (1.5-8 cm. long) axillary and 

 terminal; involucre and involucel usually lacking or the latter of a few linear 

 bractlets shorter than the pedicels; rays 2 to 10, unequal, slender, spreading- 

 ascending, 1-4 cm. long or some umbellets frequently sessile or proliferating; 

 pedicels 2 to 11, 5-20 mm. long, spreading-ascending; flowers white, the prominent 

 calyx teeth ovate, the stylopodium conic; carpophore bifid at the apex; fruit ovoid, 

 2-3 mm. long, 1.5-2.5 mm. broad, glabrous, prominently beaked at the apex, 

 rounded at the base, slightly compressed laterally or nearly terete, the narrow dor- 

 sal ribs prominent, the lateral ribs broadly corky-winged; oil tubes solitary in the 

 intervals and 2 on the commissure, the seed face plane. 



In wet places in Okla. (LeFlore Co.) and the Coastal and Blackland prairies of 

 Tex., May-July; from Tex. n. to s. Mo. and e. to La. 



22. Limnosciadium Math. & Const. 



Plants low and diffuse to erect, slender, caulescent, branching, herbaceous, 

 annual, from a fascicle of fibrous roots; leaves entire and septate or pinnate with 

 narrow elongate divisions; inflorescence dichotomously branching, of compound 

 umbels, the peduncles axillary and terminal or some umbels sessile; involucre 

 lacking or of a few narrow entire bracts; involucel of several narrow entire bract- 

 lets shorter than the pedicels; rays few, unequal, spreading-ascending; flowers 

 white, the prominent calyx teeth ovate-lanceolate, the stylopodium conic; carpo- 

 phore shortly bifid at the apex; fruit oblong-oval to orbicular, rounded at apex 

 and base, slightly compressed dorsally, glabrous, the dorsal ribs filiform, the 

 lateral broadly corky-winged; oil tubes solitary in the intervals and 2 on the com- 

 missure, the seed face plane. 



A genus of 2 species, inhabiting wet places in the south-central United States. 



1. Plant erect or assurgent; calyx teeth 0.5 mm. or less long, attached well below 

 and shorter than the stylopodium; fruit oblong-oval, 2-4 mm. long, 

 1-2 mm. broad 1. L. pinnatum. 



1. Plant low and difl'use; calyx teeth to 1.5 mm. long, attached shortly below and 

 equaling the stylopodium; fruit oval to orbicular, 2-3 mm. long, 2 

 mm. broad 2. L. pumilum 



1. Limnosciadium pinnatum (DC.) Math. & Const. Fig. 593. 



Plant erect or assurgent, 1-8 dm. high; basal leaves linear-lanceolate, acute at 

 the apex, tapering at the base, to 20 cm. long and 25 mm. wide, entire and septate 

 or pinnate, the terminal division elongate; cauline leaves pinnate or the lowest and 

 uppermost entire, with 2 to 9 linear to linear-lanceolate divisions, acute at both 



1246 



