998 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



Flora, 6 however, and the data for some of Dr. Palmer's early collections are so 

 vague, or at any rate so vaguely recorded by Vasey on the labels, that it is in- 

 advisable to include the plant in the flora of Arizona until a definite record is 

 forthcoming. 



108. MATRICARIA. False-camomile 



Animal herbs, usually 30 cm. high or less, sweet-scented, essentially 

 glabrous; leaves alternate, 2- or 3-pinnatisect into linear or linear- 

 filiform divisions; heads medium-sized, radiate or discoid, solitary at 

 the tips of the stem and branches; involucre of subequal, oblong or 

 oval, broadly scarious-margined phyllaries; receptacle conic, naked; 

 achenes small, oblong, oblique, ribbed on the inner side; pappus a 

 low crown or nearly wanting. 



Key to the species 

 1. Rays none; pappus an evident oblique crown; plant pineapple-scented. 



1. M. MATRICARIOIDES. 



1. Rays present, white; pappus obsolete; plant not pineapple-scented. 



2. M. CHAMOMILLA. 



1. Matricaria matricarioides (Less.) Porter, Torrey Bot. Club Mem. 



5: 341. 1894. 



Santolina suaveolens Pursh, Fl. Amer. Sept. 520. 1814. 

 Artemisia matricarioides Less., Linnaea 6: 210. 1831. 

 Matricaria discoidea DC, Prodr. 6: 50. 1837. 

 Matricaria suaveolens Buch., Fl. Nord. Tief. 496. 1894. Not 

 L., 1755. 



Pinal and Pima Counties, up to 2,400 feet, roadsides, waste places, 

 and river bottoms, February to April. Native from Alaska to Mon- 

 tana, Arizona, and Baja California, naturalized eastward; adventive 

 in Europe. 



Called pineapple-weed, in allusion to the pleasant odor of the plant. 



2. Matricaria chamomilla L., Sp. PL 891. 1753. 



Known in Arizona only by a collection at Phoenix (Dewey in 1891). 

 Occasionally adventive in the United States; native of Europe. 



The closely related Matricaria courrantiana DC. (M. chamomilla var. coronata 

 Boiss.), differing mainly in its conspicuous pappus, is recorded by Rydberg 7 from 

 Arizona, but Dewey's plant, the only Arizona specimen of the group seen, although 

 identified by Rydberg as M. courrantiana, has no pappus and is definitely M. 

 chamomilla. 



109. CHRYSANTHEMUM 



Annual or perennial, glabrous or sparsely pubescent, leafy-stemmed 

 herbs; leaves toothed to tripinnatisect; heads medium-sized, solitary 

 at the tips of the stem and branches, the rays white or yellow, the 

 disk yellow; involucre of scarious-margined phyllaries; receptacle 

 naked, broad, flattish; achenes 5- to 10-ribbed, sometimes narrowly 

 2- or 3-winged; pappus none. 



Several species are in cultivation as ornamentals, and the insecticide, 

 pyrethrum, is obtained from 2 of them. 



6 Gray, Asa. synoptical flora of north America. 12; 1884. (See p. 362.) 



7 Rydberg, P. A. north American flora 34: 1916. (See p. 232.) 



