476 BOTANY. 



ABRONIA 



Most of the species of this genus have been hut imperfectly characterized and are not always readily 

 determinahle from dried specimens, especially if without fruit. They seem to he distinguishable as 

 follows. 



§ 1. Fruit coriaceous, without a rigid body, the cavity extending through the entire wing; wings 

 truncate or abruptly attenuate above. 



1. A. AKENAKiA, Menz. Eoot perennial ; stems procumbent ; leaves very thick, subcordate-rounded 

 or reniform, on thick petioles ; involucral leaflets rounded or ovate, herbaceous, 2-4" long ; flowers 

 orange-yellow, fragrant ; wings rather short, (1-2" broad,) coarsely reticulate.— On the searooast from 

 S. California to Puget Sound. 



2. A. i-EAGEAUS, Nutt. Eoot perennial ; stems ascending ; leaves oblong or ovate ; involucre conspic- 

 uous, of broad ovate scarious leaflets ; flowers white ; fruit nearly as in the last. See page 284. 



3. A. TUKBLNATA, Torr. Resembling the last, but annual ; stems decumbent or ascending ; leaves 

 broadly ovate or oblong ; involucral leaflets mostly narrow-lanceolate, subherbaoeous ; flowers pink ; 

 wings of regularly formed fruit horizontally crested at the apex, narrow. See page 285, and 

 Plate XXXI. 



5 2. Body of the fruit more rigid or ligneous, the wings consisting of a single lamina. 

 * Wings more or less attenuate above and terminating below the apex of the fruit, cross-veined. 



4. A. UMBELLATA, Lam. Annual ; stems decumbent ; leaves oblong or ovate, attenuate at base into 

 a, slender petiole ; involucral leaflets small, lanceolate, subherbaceous, 2-3" long ; flowers pink ; fruit 

 mostly rigid-coriaceous, the wings often broad-rounded, submembranous. — From S. California to Wash- 

 ington Territory, confined principally to the sea-coast. Collected by Dr. Palmer in S. Utah. See 

 Plate XXXI. 



5. A. MELLIFEKA, Dougl. Leaves ovate or oblong, rounded or truncate at base ; involucral leaflets 

 oblong-lanceolate, white and scarious, 3-6" long ; flowers white ; fruit with the wings laterally elon- 

 gated and narrowed, 3-4" long. — Closely resembling the last. Oregon and Washington Territory, in the 

 interior. 



* * Wings orbicular and encircling the body, membranous and strongly reticulated. 



6. A. OYCLOPTERA, Gray. Annual ; stems ascending ; leaves oblong or ovate, more or less cuneate at 

 base I involucral leaflets ovate or narrow-Lanceolate, 2-5" long ; fruit 6-12" in diameter ; seed 2i-4" 

 long. See page 285. 



ERIOGONEiE. 



Condensed from the recent " Revision of the Eriogonese,'' by Drs. Torrey and Gray, in Proc. Aniei: 

 Acad.', Vol. VIII., pp. 145-200, (1870.) 



Tribe I. EUEEIOGONEiE. Involucre remaining unchanged, nearly always calyx-like, rarely none. 

 Leaves entire. 



* Involucre represented by the 3-4 outer empty rounded bracts surrounding the head of short-pedi- 

 celled bracted flowers. 



1. NEMACAULIS, Nutt. A single species, N. Nuitallii, Benth., of S. California; annual; leaves 

 radical and woolly ; bracts also woolly within. 



* » Involucre gamophyllous ; perigouium usually coroUa-like. 



2. EEIOGONUM, Michx. Involucre niany-few-flowered, its lobes pointless; pedicels exserted, 

 jointed to the flower, with slight bractlets at the^base ; achenium triangular. 



3. OXYTHECA, Nutt. As in the last, but the 4 involucral lobes awned, its tube naked ; achenium 

 lenticular.— Three species, all occurring in Nevada. See pages 310, 311. 



4. CENTEOSTEGIA, Gray. Involucre 1-3-flowered, 3-6-spurred near the base.— Two species, of S. 

 California ; low nearly glabrous annuals ; C. Thukberi, Gray, having an involucre with 5 ovate teeth 

 and 3 conical spurs, and C. leptocbras. Gray, with a narrowly 6-oleft involucre and 6 bristle-like spui-s. 



5. CHOEIZANTHE, E. Br. Involucre 1-flowered, unappendaged ; flower mostly included ; pedicel 

 jointed, usually short or almost wanting. 



