418 COMPOSITE. Cnicus. 



1. Scales of the involucre appressed and closely imbricated (except in the last 

 species) ; the outer scales successively shorter, not appendaged nor margined, 

 tipped with a mostly spreading prickle or point ; the innermost rarely ivith a 

 small scarious tip. 



* Low species, with simple stem and green or greenish leaves, at least when old, al- 

 though more or less cobwebby when young : heads proportionally large : anther-tips 

 sharp-pointed. 



1. C. Drummondii, var. acaulescens, Gray, 1. c. The larger forms of the 

 species (which occur in the Rocky Mountains, and from Oregon to Saskatchewan and 

 the Arctic region) have a stem from a span to a foot or even 3 or 4 feet high, and 

 large heads : the variety, which reaches California, has the more or less smaller heads 

 sessile or almost so in the centre of the tuft of radical leaves ; these lightly woolly 

 when young, at least heneath, lanceolate, not deeply pinnatifid, with short and 

 broad-margined petiole : scales of the involucre thin and proportionally large ; the 

 outer ovate-lanceolate passing into lanceolate, tapering into a weak and short or 

 slender prickle : corollas mostly reddish purple ; the lobes shorter than the throat. 



Cirsium acaule, var. Americanum, Gray in Proc. Acad. Philad. 1863. 



Open ground along the Sierra Nevada, chiefly on the eastern side. Corollas an inch or more in 

 length. The heads when several in a close cluster are smaller and narrower, when single occa- 

 sionally 2 inches long. 



2. C. quercetorum, Gray. Lightly woolly when young, and somewhat hairy : 

 stem a foot or less high, occasionally branching, leafy : leaves rather rigid, pinnately 

 or sometimes even almost bipinnately parted, more prickly : heads large and broad 

 (about two inches high) : scales of the involucre very numerous, closely appressed, 

 all but the inner ones firm-coriaceous, from oblong-ovate to lanceolate, and rather 

 abruptly tipped with a short rigid cusp or prickle : corollas apparently purple, four 

 of the lobes much higher united, the other longer than the throat. Proc. Am. 

 Acad. x. 40. 



Hills at Oakland and elsewhere near San Francisco, Bolander, Kellogg. In Bolander's specimens 

 the heads are naked-peduncled ; the outer scales veiy rigid, with thinnish and erose-ciliolate 

 margins, the outermost very short and almost ovate, all merely mucronate or cuspidate-tipped. 

 Dr. Kellogg's specimens, probably from less exposed ground, have less rigid foliage, and involucre- 

 scales more like those of G. Drummondii, less abruptly tipped with a short rigid prickle. 



* * Taller species, with permanently and densely ivhite-woolly leaves, at least under- 



neath, sometimes becoming green and naked above. 



t- Involucre globular, of flrm or thick-coriaceous closely appressed scales, tipped with 

 an abrupt spreading prickle : flowers purple, sometimes cream-color or white. 



3. C. Breweri, Gray, 1. c. Tall (4 to 10 feet high), branching, white-woolly : 

 leaves elongated and pinnatifid : heads numerous and panicled, rather small (an 

 inch or less long) : involucre at first cobwebby ; the outer scales short and broadish, 

 the back marked with a greenish or purplish thickened and somewhat glutinous or 

 glandular spot at the blunt tip, which bears a weak prickle : lobes of the corolla 

 shorter than the throat : anther-tips almost obtuse. 



In a canon near San Juan, Monterey Co. (Brewer) : and in swamps and moist grounds of 

 Strawberry Valley near Mt. Shasta (Brewer), also in Mendocino and Humboldt Counties (Bolan- 

 der, Kellogg and Harford) : near Carson City, Nevada, Anderson. The tall growth and the 

 deltoid almost blunt tip to the anther-appendages mark this species. 



4. C. undulatus, Gray, 1. c. Eather low (a foot or two high), white-woolly : 

 leaves rarely becoming naked above : heads solitary or few (from 1 to 2 inches 

 long) : involucre nearly as in the last or sooner naked, with or without the viscid 

 or greenish spot or elevated line at the tip : lobes of the corolla as long as the 

 throat: anther-tips very sharp-pointed. Cirsium undulatum (Spreng.), C. Doug- 

 lasii (DC.), and C. brevifolium, Nutt. 



