196 COMPOSIT^E. Aster. 



§ 7. ERiGERisTRUM. Iiivolucre 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 : paj^pus 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, Puksh. Tomentose-pubesceut and glabrate, a spau to 20 iiiclies high from 

 a thickish creephig 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 lialf-inch high and broader : bracts of the involucre attenuate, tomentose- 

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

 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 ? A. sahuginosus, Hook. 

 Fl. ii. 7, in part. A. consan(/uineit^,Jjedeh. Fl. Eoss, ii. 473 1 — Alaskan Islands to Arctic 

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

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

 lous-glandular and not villous. 



A. pygmseus, Lindl. Villous-pubescent and below glabrate, a span or less high and 

 lou.-<elv cespitose : stems assurgeut 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. Fl. ii. 6, & DC. 

 Prodr. v. 228 ; Torr. & Gray, Fl. ii. 154. — Arctic sea-coast, Ricliardson, Rae, &c. Seemingly 

 connects Avith Erigeron grandiJJorus ; but has subulate and very acute style-tips. 



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

 ous rigid and short bristles or squamella3 in a distinct series, inner of long capil- 

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

 of § OrtJiomeris, 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. D celling eria, 

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

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

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

 Meyer, Ehinactina, 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): bracts of the short involu- 

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

 rigid, at least some of the longer bristles clavellate: 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 cymosely disposed heads : leaves lanceolate to 

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

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

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

 Kew. iii. 199; Hoffm. Phyt. Blatt. 74, t. B, f. 2. A. ami/gdalinus, Lam. Diet. i. 305; 

 Michx. Fl. 109 ; Lindl. Bot. Reg.t. 1517. Chrjjsopsis ami/gdalina, Nutt. Gen. ii. 153. Diplo- 

 stephium umbellatum & D. aini/gdalinum, Cass. 1. c. ; DC. 1. c. 272; Diplopappus umheUatus, 

 and D. am>jgdaUnus, 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. 



