UMBELLIFER^. 315 



3. ERYNGIUM, Nicander (Button Snakeroot). Perennial herbs 

 with rigid coriaceous spinosely toothed or divided leaves, and white or 

 blue flowers sessile in dense heads which are encircled by a series of 

 bracts forming an involucre; each flower also subtended by a rigid bract. 

 Calyx-teeth manifest, rigid, persistent. Fruit ovoid or obovoid, scarcely 

 compressed, covered with hyaline scales or vesicles; ribs obsolete; oil- 

 tubes 0; carpels and seeds semi terete. 



1. E. armatum, C. & E. Bot. Gaz. xiii. 141 (1888). Diffusely branching, 

 1 ft. high or more: radical leaves oblanceolate, serrately or spinosely 

 dentate or incised, attenuate to a margined petiole; cauline narrower, 

 sessile: heads peduncled, globose, }4 in. thick; bracts of involucre 

 triangular-lanceolate, entire, thick-margined, 1 in. long and much exceed- 

 ing the head; bractlets similar and as prominent: fr. with lanceolate- 

 acuminate calyx-lobes longer than the styles. — Common in low ground, 

 on the plains and among the foothills, almost throughout the State. 



2. E. Vaseyi, C. & E. 1. c. 142. Smaller, branching above: leaves 

 oblanceolate, irregularly spinulose-serrate, attenuate at base: involucral 

 bracts narrow, rigid, spinescent at tip and spinose-toothed, 1 in. long or 

 less; bractlets similar: fr. with lanceolate acuminate-cuspidate calyx- 

 lobes exceeding the short styles. — From near Mt. Shasta southward to 

 San Luis Obispo Co. 



3. E. petiolatuia, Hook. Fl. i. 259 (1833). Erect, 1—5 ft. high, branch- 

 ing above: radical leaves oblanceolate, irregularly spinose-serrate, nar- 

 rowed to an elongated fistulous petiole, or the very lowest (submersed 

 when young) reduced to a long terete petiole; cauline mostly sessile: 

 heads peduncled, globose, ^ ^ in. high ; involucral bracts linear-lanceolate, 

 spinosely tipped and toothed, often 1 in. long; bractlets lanceolate, 

 cuspidate-tipped, little exceeding the flowers, scarious-winged below: fr. 

 with' calyx-lobes like the bractlets but smaller, shorter than the long 

 styles. Var. miniiniim, C. & E. 1. c. Only 1 — 3 in. high, all the parts 

 correspondingly reduced; bracts of the involucre equalling the heads. — 

 In marshes, but less common than the above; the variety only in the 

 Sierra, at Donner Lake, Sonne. 



4. E. articulatnin, Hook. Lond. Journ. TBot. vi. 232 (1845). More or 

 less branching, erect, decumbent or rarely prostrate: radical and lower 

 leaves consisting of a long articulated petiole with or without a small 

 lanceolate entire or laciniate blade; cauline sessile: bracts of involucre 

 ^ in. long, exceeding the heads, linear, cuspidate, spinosely toothed; 

 bractlets tricuspidate, little exceeding the flowers, the central cusp largest: 

 calyx-lobes lanceolate, cuspidate, little exceeding the styles. Var. iiiicro- 

 cephalum, C. & E. Eevis. Umb. 99 (1888). Very small and slender: 

 bracts ovate-acuminate, little surpassing the heads, these only 2 — 3 lines 



