970 FLORA. 



natives of America and Asia. Besides the following, 2 or 3 others occur in the 

 southwestern U. S. and one is nat. from Asia on the southern Atlantic and Pacific 

 coasts. 



Lower leaves spatulate, toothed; rays white. 1. L. Canadense. 



Leaves all linear or subulate, entire; rays purplish. 2. L. divaricatum. 



1. Leptilon Canadense (L.) Britton. Horse-weed. Canada Fleabane. 

 (I. F. f. 3827.) Stem hispid-pubescent, or glabrate, 7-30 dm. high, the larger 

 plants paniculately much branched. Leaves usually pubescent or ciliate, the basal 

 and lower spatulate, petioled, incised, dentate or entire, 2-10 cm. long, obtuse or 

 acutish, those of the stem linear and mainly entire; heads usually very numerous; 

 about 4 mm. broad; involucre, 2-3 mm. high, its bracts linear, acute, glabrate; 

 rays numerous, white, shorter than the pappus and mostly shorter than their tubes. 

 In fields and waste places, a common weed throughout N. Am., except the extreme 

 north. Widely distributed as a weed in the Old World and in S. Am. June-Nov. 



2. Leptilon divaricatum (Michx.) Raf. Low Horse-weed. Purple 

 Horse-weed. (I. F. f. 3828.) Stem diffusely much branched, 7-30 cm. high, pubes- 

 cent or hirsute. Leaves all linear or subulate, entire, 8-25 mm. long, about 1 mm. 

 wide, the uppermost minute; heads numerous, about 4 mm. broad; involucre 2 mm. 

 high, its bracts linear, acute, pubescent; rays purplish, shorter than their tubes. 

 In sandy soil, especially along rivers, Ind. to Minn., S. Dak., Tenn., La., Neb. 

 and Tex. June-Oct. 



37. DOELLINGERIA Nees. 



Perennial leafy herbs, the lower leaves reduced to scales or sheaths, the upper 

 large, mostly entire, acute or acuminate in our species. Basal leaves none. 

 Heads corymbose; involucre campanulate to hemispheric, its bracts imbricated in 

 several series, appressed, thin, sometimes scarious-margined, their tips not herba- 

 ceous nor foliaceous. Receptacle foveolate. Ray-flowers white, pistillate, not very 

 numerous. Disk-flowers perfect, the corolla with a slender tube abruptly expanded 

 into a campanulate 5-lobed limb, white to greenish in our species. Anthers obtuse 

 at the base; style-appendages ovate to subulate (rarely obtuse). Achenes obovoid. 

 Pappus double, the outer series of numerous short bristles or scales, the inner of 

 long capillary bristles, some or all of which have thickened tips. [In honor of 

 Th. Dollinger, botanical explorer.] About 4 species, natives of eastern N. Am. 



Leaves lanceolate to ovate ; heads mostly numerous. 



Leaves lanceolate to oblong-lanceolate, acuminate. 1. D. umbellata. 



Leaves ovate to ovate-lanceolate, acute. 2. D. humilis. 



Leaves, at least the lower, obovate ; heads commonly few. 3. D. infirma. 



1. Doellingeria umbellata (Mill.) Nees. Tall Flat-top White Aster]' 

 (I. F. f. 3829.) Stem glabrous or pubescent above, striate, corymbosely branched 

 at the summit, 6-25 dm. high. Leaves glabrous above, usually pubescent on th$ 

 veins beneath, membranous, narrowed at the base into short petioles, or the upperjJ 

 most sessile, hispid-margined, those of the stem 12-15 cm - lon g> l ~ 2 -5 cm - w j de 5 

 heads 12-25 mm. broad, in terminal compound corymbs ; involucre 3-4 mm. highlJ 

 its bracts lanceolate, usually pubescent or ciliate. acutish or obtuse; rays 10-15J 

 white; style-appendages ovate, acute; achenes nerved, slightly pubescent. In moist 

 soil, Newf. to Ga., west to the N. W. Terr., Mich, and Ark. July-Oct. 



Doellingeria umbellita piibens (A. Gray) Britton. Under leaf-surfaces pubescent. 

 Mich, to the N. W. Terr. 



2. Doellingeria humilis (Willd.) Britton. Broad-leaved Flat-top White 

 Aster. (I. F. f. 3830.) Similar to the preceding species, usually lower, seldom 

 over 12 dm. high. Stem striate, corymbosely branched above, glabrous, or some- 

 what pubescent. Leaves rather firm, sessile, or the lower very short-petioled, nar. 

 rowed, or sometimes rounded at the base, rough -margined, those of the stem 2-7 

 (in. long, 12-50111111. wide, inflorescence as in D. umbellata; achenes somewhat 

 pubescent. In moist soil, southern N. J. and Penn. to Fla. and Tex. July-Sept. 



3. Doellingeria infirma (Mirhx.) Greene. Cornel-leaved Aster. (I. F. 

 f. J83I.) Stem slender, glabrous, orroughish above, sparingly branched at the 

 summit, terete. 4-9 dm. high. Leaves entire, hispid-margined, glabrous above, 



