192 PROCEEDINGS OF THE AMERICAN ACADEMY 



laxa sect. Mucronece. — Annua?, Californica?, demissas, fere glabrae, foliis 

 radicalibus spathulatis, ramealibus bracteisve saepius trifidis, lobis aris- 

 tulatis, involucris subsessilibus. Genus inter Chorizanthem (Mucro- 

 neam) et Oxythecam. 



1. C. Thurberi, Gray, 1. c. Glabra; involucro 1 - 2-floro char- 

 taceo venuloso apice tantum 5-dentato, costis baud prominulis, cal- 

 caribus 3 grossis conicis dentibusque ovatis breviter cuspidatis ; peri- 

 goniisegmeutis lineari-spathulatis basin versus hirsuto-ciliatis. (Embryo 

 incurvo-excentricus, radicula longa.) San Felipe, Thurber, who alone 

 has met with it. 



2. C. leptoceras, Gray in herb. Kew. Glabella ; ramis divaricatis; 

 involucro hirsutulo 2 - 3-floro 6-fido, dentibus lanceolato-subulatis aris- 

 tatis (arista unico longiore), calcaribus 6 aristiformibus apice uncinatis 

 tubo dimidio brevioribus ; perigonii segmentis ovalibus dorso parce 

 pilosis. — Plains of San Gabriel, Lobb in herb. Kew. 



5. CHORIZANTHE, R. Br. 



Involucrum uniflorum, gamophyllum, basi inappendiculatum, tubo 

 saepius angulato vel costato, dentibus lobisve 2-6 fere semper cuspide 

 vel arista terminatis ssepius inaequalibus. Flos inclusus vel parum 

 exsertus, in involucro subsessilis seu breviter pedicellatus. Perigoniura 

 tenue vel corollinum, 6-lobum vel 6-partitum. Stamina 9, raro 3 vel 

 6. Achenium trigonum. Embryo Eriogoni, nunc rectus cotyledonibus 

 angustioribus, nunc incurvo-excentricus vel cotyledonibus latis radicular 

 pi. m. accumbentibus. — Plantar humiles, involucris sessilibus cymoso- 

 congestis vel sparsis, foliis oppositis verticillatisque seu inferioribus 

 saapius alternis. — Ghorizanthe & Mucronea, Benth. Eriog. & in DC. 

 1. c. Acanthogomim, Torr. 



§ 1. Euchorizanthe. Involucrum tubulosum, 6-dentatum, 6- 

 costatum, angulatum, saspius coriaceum, costis validis in cuspidem 

 vel aristam sajpius pi. m. uncinatam excurrentibus. Stamina 

 juxta basim perigonii 6-lobi inserta. Folia nunquam cordata, 

 integra, saltern caulina angusta basi attenuata. 



* Annua?, Californica;, Scariosce, nerape iuvolucris in glomerulas 

 capituliformes congestis, limbo pi. m. albo-scarioso (necnon praa- 

 cocibus vegetioribus in dichotomiis pi'imariis solitariis ex toto 

 herbaceis). 



