COMPOSITE. 433 



stocks. Leaves opposite. Heads small, on slender pedicels, in an ample 

 panicle. Flowers diurnal, white. Ray-achenes 6— 8, oboompressed, com- 

 pletely enclosed, smooth, surmounted by a short saucer shaped hyaline 

 entire persistent pappus Disk-achenes with a pappus of 2 slender, de- 

 ciduous palese. Receptacle flat, with a circle of united chaff between 

 disk and ray. 



1. H. iliipes, Greene, Bull. Torr. Club, ix. 122 (1882); H. & A. Bot. 

 Beech. 356 (1841), under He^aizoaia. Stems decumbent, 2 ft. high; 

 slender branchlets and filiform peduncles glabrous or glandular: cauliue 

 leaves linear, minutely villous; those of the branches with some short- 

 stipitate dark glands: involucre loosely villous: rays white or rose-tinted, 

 deeply cleft into 3 linear lobes.— By streamlets in the hills east of Napa 

 Valley, and in low fields along Napa River; also foothills of the Sierra 

 in Calaveras Co. July — Oct. 



70. PTILOXELLA, NutlaU. Slender annuals with alternate narrow 

 entire leaves and corymbose- panicled heads of white vespertine flowers. 

 Heads with 3—6 rays, and nearly twice as many disk-flowers. Receptacle 

 chaffy throughout, the palese thin, subscarious, and like the involucral 

 bracts partly embracing the achenes. Achenes turbinate, silky-villous, 

 crowned with a pappus of pectinate-plumose narrow scales. 



1. P. scabra, Nutt. Trans. Am. Phil. Soc. vii. 386 (1841); Hook. Fl. 

 i. 316 (1833), under BlepJiaripappus. A few inches to a foot high, sca- 

 brous throughout, also somewhat hispid below, and glandular above; 

 the narrowly linear leaves wi^i revolute margins when mature or dry: 

 heads many, terminating the slender and usually somewhat fastigiate 

 branchlets; flowers vespertine. Var. subcalva (Gray), differs from- the 

 type in having the pappus very much reduced, or even obsolete. — Com- 

 mon along the eastern base of the Sierra, especially northward. June — 

 Sept. 



2. P. Isevis. Blephanpappus Ixvis, Gray, Bot. Gaz. xiii. 73 (1888). 

 Glabrous and mostly smooth up to the heads, these smaller than in the 

 preceding, their fewer flowers diurnal: leaves all small and appressed, 

 the uppermost reduced almost to mere scales. — Range of the preceding, 

 but less common. 



Suborder 7, Helenioide.?^. 



Herbs seldom viscid or balsamic. Receptacle naked. Bracts of invo- 

 lucre herbaceous mostly uniserial and equal, sometimes concave behind 

 the ray-achenes, but never enfolding them. Style branches of perfect 



