APPENDIX. 477 



*" • * Involucre none. 



6. LASTAERLEA, Eemy. Perigonium subcoriaoeous and resembling the involucre of Chorizantke; 

 stamens inserted at the throat.— A single Chilian species, L. Chilensis, Eemy, introduced into Cali- 

 fornia. 



Tribe II. PTEEOSTEGIEiE. Involucre of a single 2-lobed bract embracing the solitary flower, be- 

 coming dilated and reticulated in fruit and 2-gibbous-saccate on the back. 



7. PTEEOSTEGIA, P. & M. Two species of Southern and Lower California, annuals, with opposite 

 more or less lobed and sometimes toothed leaves ;— P. drymaeioidbs, P. & M., with the fruiting involu- 

 cre 1-lJ" long, dentate on the margin ; and P. macroptera, Benth., with the involucre i' long, sinuate- 

 margined. 



ERIOGONUM. 



§ 1. ALATA, Benth. Achenium 3-winged ; embryo in the axis, straight or neai-ly so ; calyx 6-parted, 

 not produced at base. Perennials or biennials, the scapelike stems 1-3° high ; involucres mostly 

 loug-peduncled, loosely cymose-panicled ; leaves radical, spatulate or lanceolate ; pubescence loose. 



1. E. IIIERACIFOLIUM, Benth. Cinereous-pubescent, the leaves subtomentose and somewhat silky- 

 villous ; flowers more or less pubescent, with the filaments and ovary subhirsute, yellow, (or rose-color ;) 

 panicle many-flowered ; achenium winged only above the middle. — ^W. Texas. 



2. E. ALATtjM, Torr. Tall, more or less hirsute-villous ; panicle decompound ; flowers glabrous, 

 small, yellowish; invoulcres numerous, 5-toothed; achenium winged nearly to the base, wings rather 

 broad, thin. — From the Platte to W. Texas and New Mexico. 



3. E. ATRORUBENS, Eng. Leavos villous-pubescent ; scape more or less inflated, dichotomously di- 

 vided into a loose cyme ; involucres few, long-peduncled, 5-7-toothed ; flowers glabrous, reddish ; wings 

 as long as the achenium, narrow and thickened. — Chihuahua. 



§ 2. EEIANTHA, Benth. Achenium wingless, (as in all the remaining sections;) embryo straight, 

 axile, the radicle shorter than the broad cotyledons ; flowers villous or silky, with a narrow elon- 

 gated base. Perennials, with branching leafy stems, alternate or vertioillate leaves, tomentose 

 beneath, and solitary mostly sessile involucres. 



* Leaves alternate, narrow ; panicle open, naked ; calyx herbaceous, the lobes alike. 



4. E. LONGU'OLIXJM, Nutt. Tall, 2-4° high ; lower involucres more or less peduncled. — Florida, Ar- 

 kansas and Texas. 



* ' Leaves in whorls of 3-5, oval or oblong ; cyme dichotomous, leafy ; involucres sessile, many- 

 flowered ; calyx white and somewhat corolla-like, inner lobes often the longer. 



5. E. TOMENTOSTJM, Mx. Tall, herbaceous, very leafy ; leaves obovate or oval, flat, tomentum col- 

 ored ; calyx tomentose, the tube elongated, lobes broadly ovate. — South Carolina to Florida. 



6. E. UNDULATUM, Beuth. Low and woody ; leaves undulate ; flowers smaller. — Mexico. 



7. E. Jambsii, Benth. Low, woody at base ; cauline leaves few, spatulate or oblong, tomentum 

 white ; calyx viUous-silky, with obovate or spatulate lobes. — From the Platte to W. Texas and New 

 Mexico. 



§ 3. UMBELLATA, Benth. Flowers as in § 2 ; involucres many-flowered, solitary or rarely capitate, 

 or in simple or compound terminal umbels ; ovary usually sparingly hirsute above ; embryo nearly 

 straight, equaling or exceeding the more or less eccentric cotyledons. — Peremiials, mostly low, 

 sometimes woody ; leaves usually white- woolly and mostly spatulate ; flowers nearly always 

 yellow. 



* Calyx villous or pubescent externally, (except in E. Kellogii.) 



(a.) Involucre campanulate, repand-dentate with 5-7 teeth ; umbel usually many-rayed with an in- 

 volucre of as many (2-8) about equal leaves ; embryo straight. 



8. B. PLAVUM, Nutt. Silky-woolly ; scapes 3-6' high ; leaves spatulate or lance-oblong or subovate, 

 crowded ; calyx yellow, silky-villous, 3" long. — From the SaskatchcAvan to W. Kansas and Colorado ; 

 Oregon. 



(b.) Involucre lobed, solitary, naked, or sometimes 2-3 together in an imperfect 2-3-rayed umbel or 

 head ; embryo eccentric, often incurved. The first species with small leaves and a top-shaped invo- 

 lucre with broad scarcely spreading teeth, the remainder larger-leaved and the deeply 6-8-cleft 

 involucre with narrow and at length reflexed lobes. , 



9. E. THYMOIDES, Benth. Woody, csespitose, cinereons-tomentose, the numerous branches very leafy 

 at base, a span high ; leaA'es 2-3" long, margin revolute ; the peduncle with a whorl below the middle ; 

 calyx densely Tetrorse- villous at base. — Washington Territory. 



