648 PKOCEEDINGS OF THE AMERICAN ACADEMY 



(which may at length be deeiduons ?), broadly-spatulate or cuneate- 

 obovate, one or two inches long, including the long-attenuate base or 

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

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

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

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

 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 discura vix superante ; disci herraaphroditis, 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 fl. harm, 

 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 monocephahs inferne aphyllis ; 

 floribus luteoHs vel albidis ? 



RiGiOPAPPUS LEPTOCLADUS. — Dalles of the Columbia River, 

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

 from the Herbarium of the Royal Gardens, Kew. 



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



Capitulum modo Harpcecarpi pauciflorum ; floribus radii 4 — 5, 

 ligula brevissima styli ramos haud superante, disci ad unicum rare 

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

 radii pi. m. obcompressa, subincurva. — Herbse annual, tenellse, foliis 

 linearibus hirsutis fere eglandulosis. Acheniis exceptis ad Harpecar- 

 pum referenda^. 



Hemizonia (Hemizonella) minima : caule tenuissimo subpolH- 

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

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

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



