196 COMPOSIT^E. Aster. 



§ 7. ERiGEEiSTEUM. Involucre of Erigeron, i. e. broad, of very many and- 

 narrow acute or attenuate bracts, all of the same length, herbaceous, with no dis- 

 tinction of body and tip : rays numerous and narrow : pappus simple : heads soli- 

 tary, or rarely two, large, terminating the simple stem : this leafy to the top, in 

 which and in the acute style-tips the section differs from Erigeron, to which it 

 makes transition : arctic and subarctic species. 



A. peregrlnUS, Puesh. Tomentose-pubescent and glabrate, a span to 20 inches high from 

 a thickish creeping rootstock : leaves oblong-lanceolate or upper ovate-lanceolate, these 

 closely sessile by partly clasping base (inch or two long), either entire or sharply denticulate- 

 serrate: head half-inch high and broader: bracts of the involucre atteunate, tomentose- 

 pubescent or villous, not at all viscid or glandular : rays hali-inch long, violet-purple. — 

 11. ii 556 ; Torr. & Gray, Fl. ii. 155 ; Herder in PI. lladd. ii. 10, in part. A. Unalaschensis, 

 Less, in Linn. vi. 122. A. Tilesii, Wikstr. in Act. Holm. 1822, 13 'i A. salsuginosus, Hook, 

 n. ii. 7, in part. A. consanc/uineus, Ledeb. Fl. Pujss, ii. 473 ? — Alaskan Islands to jVrctic 

 coast; first coll. by Nelson. (Arct. E. Asia.) Has been confused with A. salsuginosus, 

 Richards., now removed to Erigeron, which is naked-stemmed above, its involucre viscidu- 

 lous-glandular and not villous. 



A. pygm^US, Lixdl. Villous-pubescent and below glabrate, a span or less high and 

 loosely cespitose : stems assurgent from a slender rootstock or creeping base : leaves lingu- 

 late-lanceolate to linear, entire, obtuse, nearly veinless (mostly an inch long) : head about 4 

 lines high, solitary: bracts of the involucre spreading, linear, acute or obtuse, flaccid, 

 densely or sparsely villous : rays 30 or more, apparently violet. — Hook. PL ii. 6, & DC. 

 Prodr. V. 228 ; Torr. & Gray, Fl. ii. 154. — Arctic sea-coast, Richardson, line, &c. Seemingly 

 connects with Erigeron grandlflorus ; but has subulate and very acute style-tips. 



§ 8. DcELLiNGERiA. Pappus manifestly rlouhle ; outer setulose, i. e. of numer- 

 ous rigid and short bristles or squamellae in a distinct series, inner of long capil- 

 lary bristles, some of which are usually clavellate-thickened at the tip : involucre 

 of § Orthomeris, i. e. bracts destitute of herljaoeous tijss and tliin-coriaceous. 

 shorter than the disk: rays not numerous (8 to 13), always white: disk-corollas 

 barely yellowish : akenes mostly obovate, several-nerved : heads corymbosely cy- 

 mose (rarely solitary) at summit of stem or sparing branches, not large : leaves 

 mostly entire, not rigid, veiny: pappus becoming tawny. — (Jrav, Proc. Am. 

 Acad. xvi. 98. Diplostep/iium, Cass. Diet, xxxvii. 486, not HBK. Dcellingeria. 

 Nees, Ast. 176, excl. spec. Diplostephium, § 1, DC. Prodr. v. "27-2, excl. spec. 

 Diplopappus § Triplopappiis, Torr. & Gray, Fl. ii. 182. (The most distinct sub- 

 genus, even worthy of generic rank, except for some transitions. A. obovatiis, 

 Meyer, Rhinactina, Less., has similar pappus, but is otherwise as Xglorrhiza.) 



* Leaves acute or acuminate, all entire, generally green and almost plabrous, with loose veins and 

 beneath a minute reticulation of veinlets (visible only under a lens): bract* of the short involu- 

 cre mostly obtuse: akenes turgid-obovate at maturity, glabrate or f;labrous : pappus rather 

 rigid, at least some of the longer bristles cliivellate: disk-corollas deeply 5-lobed. 



A. umbellatus, Mill. Stem 2 to 7 feet high, generally tall and corymbose at summit, 

 very leafy, bearing numerous rather crowded lymosely dis]iosed heads : ica^■es lanceolate to 

 oblong-lanceolate (3 to 6 inches long), acuminate and with tapering liasc : involucre hardly 

 longer than the akenes; its bracts lanceolate-linear, rather obtuse: st\ le-ajipendanes del- 

 toid-ovate, acutish: stronger pappus-bristles delicately clavellatc.— Diet. ed. 7, no. ^2; .\it. '' 

 Kew. iii. 199; Hoffm. Phyt. Blatt. 74, t. B, f. 2.' A. aiiujgdalimis. Lam. Diet, i.' 305 ; 

 Michx. Fl. 109 ; Lindl. Bot. lieg. t, 1517. Cl.ri/xopsis nmi/gdaii'im, Xutt. Gen. ii. 153. Diplo- 

 stephium nmhnllatum & D. nmi.gdalinum, Cass. 1. c. ; DC. 1. c. 272; Jjli.lopnppus umhrllntiis, 

 and D. oni;,,,dalin„s, partly, Torr. & Gray, I.e. 183. —Low grounds, Newfoundland, S. L.ab- 

 rador,and Sasl<atchewan to Arkansas and Ceorgia; the typical form commoner northward: 

 low forms with broader and more scabrous leaves common sonthwai-d. 



