410 COMPOSITE. Senecio. 



leaves rigid, almost aeerose but pointless, impressed-punctate : head 10-16-flowered, 

 fully half an inch long; scales of the involucre about 12 in a single series, with tips 

 resembling the leaves, and the thinner base somewhat .dilated: akenes (or rather 

 ovaries) oblong. — Peucephyllum Schottii, Gray, Bot. Mex. Bound. 74. 



Colorado bottom in Sonora (Mexico), Schott, Feb. 3, 1855. A flowerless specimen collected 

 by Dr. Newberry on the " Colorado of California, January 15," may be this ; but is more gluti- 

 nous, and is perhaps a Bigelovia or Aplopappus. Leaves an inch or less in length, punctate in 

 the manner of Aplopappus and of many Eupatoriacece. The flowers were said to he yellow, but 

 they seem to have been only yellowish. The style-branches are like those of Luina, or more 

 obtuse, and wholly destitute of any appendage or tip. 



101. SENECIO, Linn. Groundsel. 



Head many-flowered, with pistillate rays, or occasionally homogamous by the want 

 of the rays ; the flowers all fertile. Scales of the involucre herbaceous, mostly 

 narrow, equal in a single series, or calyculate with a few short scales at the base. 

 Receptacle fiat or merely convex, naked. Disk-corollas usually narrow, 5-toothed 

 or 5-lobed. Style-appendages of the disk-flowers mostly capitate-truncate, the apex 

 minutely tufted or hispid, rarely with a little cusp. Akenes terete or somewhat 

 angled, usually 5- 10-ribbed. Pappus of very numerous and mostly white fine and 

 soft capillary and merely scabrous bristles. — Herbs or shrubby plants ; with alter- 

 nate leaves, and usually corymbose or solitary heads of yellow flowers (at least in all 

 the American species) : akenes commonly glabrous, or beset with some short hairs 

 or papilke, which become turgid when wetted, open at the apex, and emit -one or 

 two uncoiling spiral threads. 



This is counted as the largest genus of Phamogamous plants (of little under 1,000 species), and 

 is very widely spread over the world, the species of each great region for the most part peculiar. ' 

 But North America is by no means rich in species, the central regions, however, more so than 

 either the Atlantic States or the Pacific slope. 



S. Cineraria, DC, of the Mediterranean region, a common house-plant (known in cultiva- 

 tion as the Dusty Miller, from its whiteness), is in Kellogg and Harford's distributed collection, 

 said to have been gathered on the shore of the Bay of San Francisco, near Alameda. It is doubt- 

 less a waif from cultivation. 



S. ? flocciferus, DC, is Malacothrix saxatilis. 



* Moot annual : rays none or minute : weeds introduced from Europe into ivaste or 



cultivated grounds. 



1. S. vulgaris, Linn. A span to a foot high, branching, leafy to the top : 

 leaves clasping at base, pinnatifid ;' the oblong lobes and the spaces between them 

 sharply toothed: scales at the base of the involucre conspicuous and blackish- 

 tipped : rays none. 



Near San Francisco, &c. : the common Groundsel of Europe. 



2. S. sylvaticus, Linn. More slender : leaves less clasping and with narrower 

 lobes : heads smaller : scales at the base of the involucre few, minute, not blackish : 

 rays present but minute, hardly longer than the disk-flowers. 



Introduced from Europe : San Luis Obispo (Brewer), and San Diego, Cooper. Mare Island, 

 Greene. 



* * Root annual : rays conspicuous : indigenous species. 



3. S. Californicus, DC. A foot or two high, with slender rather simple stem, 

 glabrous or with some scattered hairs: leaves lanceolate, linear, or the lowest oblong, 

 varying from sparsely denticulate to pinnatifid ; the cauline with mostly clasping 

 base ; their lobes oblong or broadly linear : heads corymbose : rays elongated : 

 akenes canescent. — S. Coronopus, Nutt., a form of this with the leaves deeply or 

 even doubly pinnatifid. 



