196 COMPOSITE. Aster. 



7. ERIGER/STRUM. 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. peregrinus, PUESH. Tomentose-pubescent and glabrate, a span to 20 indies 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 attenuate, tomentose- 

 pubesceut or villous, not at all viscid or glandular : rays half-men long, violet-purple. 

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

 Less, in Linn. vi. 122"? A. Tilesii, Wikstr. in Act. Holm. 1822, 13 1 A. salsuginosus, Hook. 

 Fl. ii. 7, in part. A. com-.niiijuinc.us, Ledeb. Fl. Ross, ii. 473 .' Alaskan Islands to Arctic 

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

 Ivirharils., now removed to Erigeron, which is naked-stemmed above, its involucre viscid u- 

 lous-glandular and not villous. 



A. pygm^US, LINDL. Villous-pubescent and below 12 Iain-ate, a span or less high and 

 loosely cespitose : steins assurgent from a slender rootstock or creeping base : leaves lingn- 

 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. Fl. ii. 6, & DC. 

 Prodr. v. 228 ; Torr. & Gray, Fl. ii. 154. Arctic sea-coast, Richtirdson, Uae, &c. Seemingly 

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



8. DCELLINGERIA. Pappus manifestly double ; 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 herbaceous tips and thin-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. Gray, Proc. Am. 

 Acad. xvi. 98. Diplostephium, Cass. Diet, xxxvii. 486, not IIBK. Dcellingeria, 

 Nees, Ast. 176, excl. spec. Diplostephium, 1, DC. Prodr. v. 272, excl. spec. 

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

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

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



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

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

 cre mostly obtuse: akenes turgid-obovate at maturity, glabrate or glabrous: pappus rather 

 riyid, at least some of the longer bristles clavellate: disk-corollas deeply 5-Ljbcd. 



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

 very leafy, bearing numerous rather crowded cymosely disposed heads : leaves lanceolate to 

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

 longer than the akenes ; its bracts lanceolate-linear, rather obtuse : style-appendages del- 

 fcoid-ovate, acutish : stronger pappus-bristles delicately clavellate. Diet. ed. 7, no. 2; Ait. 

 Kcw. iii. 199; lloffm. Phyt. Blatt. 74, t. B, f. 2. A. anti/t/finliniis, Lam. Diet. i. 305; 

 Alichx. Fl. 109; Lindl. Bot. Reg. t. 1517. Chrysopsis amygdalina,~Nutt.Gen.ii.l53. L>//>lo- 

 stephium umbellatum & D. amygdalinum, Cass. 1. c. ; DC. I.e. 272; Diplopappus umbel/atita, 

 and />. amygdalinus, partly, Torr. & Gray, I.e. 183. Low grounds, Newfoundland, S. Lab- 

 rador, and Saskatchewan to Arkansas and Georgia; the typical form commoner northward : 

 low forms with broader and more scabrous leaves common southward. 



