548 PROCEEDINGS OF THE AMERICAN ACADEMY 



(which mav nt Ipno-th hp dpfirlnnns ?^. hvonrllv-spntnlatf or cuneate- 

 obovate, one or two inches long, ini;luding tne iong-attenuate base or 

 petiole. Scapes from 2 to 4 inches high, naked or with a few small 

 linear bracts, viscous-pnbescent, but entirely destitute of the white 

 wool, as is the involucre also. Head about as large as that of II. nana, 

 the involucre similar. The broad and truncate, eroded, silvery paleae 

 of the pappus are one fourth or nearly one third the length of the silky- 

 villous achenia. 



RIGIOPAPPUS, Nov. Gen. Heleniearum. 



Capitulum pluriflorum, heterogamum ; floribus radii 5-8 fcemineis, 

 ligula parva discum vix superante ; disci hermaphroditis, corolla tubu- 

 losa angusta 3 - 4-dentata, dentibus brevissimis. Involucrum biseriale, 

 floribus brevius, e squamis subulato-linearibus rigidis foliis ramealibus 

 conformibus. Receptaculum planum nudum. Styli rami i\. herm. 

 parte stigmatosa brevi glabra (more Asteroidearum) complanata in ap- 

 pendicem gracilem subulatam hirtellam producta. Achenia gracilia, 

 linearia, compressa, hispidula, transverse rugulosa. Pappus simplex, 

 e paleis 4-5 rigidis subcorneis aristiformibus (angusto-subulatis corol- 

 1am superantibus achenio ipso paullo brevioribus) constans. — Herba 

 annua, gracilis, puberula ; foliis alternis linearibus ; ramis floriferis ex 

 apice caulis simplicis paucis filiformibus monocephalis inferne aphyllis ; 

 floribus luteolis vel albidis ? 



IviGiOPAPPrs LEPTOCLADUS. — Dalles of the Columbia River, 

 Oregon, Dr. Lyall, coll. Oregon Boundary Commission ; communicated 

 from the Herbarium of the Royal Gardens, Kew. j /"•^'L^* • 



HEMIZONIA, DC, Torr. & Gray, § Hemizonella. 



Capitulum modo Harpcecarpi pauciflorum ; floribus radii 4-5, 

 ligula brevissima styli ramos baud superante, disci ad unicum rare 

 duos intra cupulam 3-5 dentatam reducti. Achenia omnia perfecta ; 

 radii pi. m. obcompressa, subincurva. — Herba3 annuae, tenellaj, foliis 

 linearibus hirsutis fere eglandulosis. Acheniis exceptis ad Harpecar- 

 pum referenda}. 



Hemizonia (Hemizonella) minima : caule tenuissimo subpolli- 

 cari 1 - 3-cephalo ; foliis brevibus, summis capitula sessilia involucrau- 

 tibus eaque vix superantibus ; acheniis glabris, radii obovatis erostris. 

 — Dry soil, near Soda Springs, alt. 8,680 feet. Leaves 1^ to 2 lines 



