Genus 37. 



THISTLE FAMILY. 



443 



37. DOELLINGERIA Nees, Gen. & Sp. Ast. 177. 1832. 



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, 

 usually numerous ; involucre campanulate to hemispheric, its bracts imbricated in several 

 series, appressed, thin, sometimes scarious-margined, their tips not herbaceous nor foliaceous. 

 Receptacle foveolate. Ray-flowers white, pistillate, not very numerous. Disk-flowers per- 

 fect, 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 subu- 

 late (rarely obtuse). Achenes obovoid, glabrous, or pubescent. Pappus double, the outer 

 series of numerous short bristles or scales, the inner series of long capillary bristles, some 

 or all of which have thickened tips. [In honor of Th. Dollinger, botanical explorer.] 



About 5 species, natives of eastern North America. Type species: Doellingeria umbeUata 

 (Mill.) Nees. 



Leaves lanceolate to ovate ; heads mostly numerous. 



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



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



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



i. Doellingeria umbeUata (Mill.) Xees. Tall Flat-top White Aster. Fig. 4380. 



Aster umbellatus Mill. Gard. Diet. Ed. 8, No. 22. 1768. 

 Diplopappus umbellatus Hook. Fl. Bor. Am. 2 : 22. 1834. 

 D. umbeUata Nees, Gen. & Sp. Ast. 178. 1832. 

 Aster umbellatus var. pubens A. Gray, Syn. Fl. 1 : Part 



2, 197. 1884. 

 D. pubens Rydb. Bull. Torr. Club 37: 147. 1910. 



Stem glabrous or pubescent above, striate, corym- 

 bosely branched at the summit, i-8 high. Leaves 

 lanceolate to oblong-lanceolate, ascending, glabrous 

 above, usually pubescent at least on the veins be- 

 neath, membranous, acuminate at the apex, nar- 

 rowed at the base into short petioles, or the upper- 

 most sessile, hispid-margined, those of the stem 

 S'-6' long, i'-i' wide; heads numerous, 6"-io" broad, 

 in terminal compound corymbs ; involucre broadly 

 campanulate or hemispheric, li"-2" high, its bracts 

 lanceolate, usually pubescent or ciliate, acutish or 

 obtuse, imbricated in 3 or 4 series, the outer shorter; 

 rays 10-15, white; style-appendages ovate, acute; 

 pappus nearly white ; achenes nerved, slightly pu- 

 bescent. 



In moist soil, Newfoundland to Georgia, Saskatche- 

 wan, Iowa and Michigan. Iuly-Oct. 



2. Doellingeria humilis (Willd.) Britton. 

 Broad-leaved Flat-top White Aster. 

 438i. 



Fig. 



Pennsylvania, Florida and Texas. 



Aster humilis Willd. Sp. PI. 3: 2038. 1804. 



D. amygdalina Nees, Gen. & Sp. Ast. 179. 1832. 



Aster umbellatus var. latifolius A. Gray, Syn. Fl. 1 : 



Part 2, 197. 1884. 

 Doellingeria humilis Britton, in Britt. & Brown, 111. Fl. 



3: 392. 1898. 



Similar to the preceding species, usually lower, 

 seldom over 4 high ; stem striate, corymbosely 

 branched above, glabrous, or somewhat pubescent. 

 Leaves ovate to ovate-lanceolate, rather firm, ses- 

 sile, or the lower very short-petioled, acute or short- 

 acuminate at the apex, narrowed, or sometimes 

 rounded at the base, rough-margined, those of the 

 stem l' 3' long. -2' wide, inflorescence as in D. 

 umbellatus; pappus dirty white; achenes somewhat 

 pubescent. 



In moist soil, eastern Massachusetts to New Jersey, 

 Perhaps a broad-leaved race of the preceding species. July-Sept. 



