OF AETS AND SCIENCES. 49 



whitened beneath, have no evident tomeutum ; the heads are compara- 

 tively large and broad, in loose panicles. First collected in the moun- 

 tains of S. Colorado by Gunnison, later by Rothrock in those of S. E. 

 Arizona, and by Greene in S. New Mexico. 



Artemisia Bolanderi. Seriphidium, between A. trijida and A. 

 cana, referred to the former in Bot. Calif, i. 405 : the characters 

 indicated in the subjoined conspectus of the group. * 



* ARTEMISIA, § Seriphidium, Besser. 



The North American species, which have niucli needed revision, liave been 

 arranged for the Synoptical Flora of North America essentially as follows : — 



1. Anomalous species, mainly herbaceous, tall, with ample compound panicles, 

 and heads more or less nodding in anthesis. — S. California. 



A. Parishii, Gray, Proc. Am. Acad. xvii. 220. Has the anomaly of sparsely 

 arachnoid-villous akenes. 



A. Palmeri, Gray, Proc. Am. Acad. xi. 79. Anomalous in having palese on 

 the receptacle, subtending most of the flowers. 



2. Sage-brush, low shrubs or suffruticulose plants of the interior dry regions, 

 canescent ; the heads erect even when young. 



* Foliose-spicate ; the heads solitary and sessile in the axils and all surpassed 



by the mostly 3-parted rigid and almost acerose leaves. 



A. RiGiDA. A. trijida, var. rigida, Nutt. Trans. Am. Phil. Soc. n. ser. vii. 398. 

 — Only sterile specimens were known to the discoverer; the flowering plant, 

 collected by Cusick in Eastern Oregon, confirms Nuttall's conjecture that it is a 

 peculiar species. 



* * Thyrsoid-paniculate, &c. ; at least the upper heads or clusters exceeding 



the subtending and not rigid leaves. 



•1- Heads comparatively small and few-flowered, mostly oblong. 



A. ARBUscuLA, Nutt. 1. c. Dwarf, with stout woody base but slender flower- 

 ing branches, along which the heads, subtended by small leaves or bracts, are 

 spicately or paniculately scattered: involucre 5-9-flowered : leaves on the main 

 stem cuneate and dilated, o-lobed or parted, and lobes sometimes again 2-3- 

 lobed. There are two forms, both represented among Nuttall's specimens ; one 

 with more campanuliite 7-9-flowered involucre ; in the other this is oblong, 4-5- 

 flowered, and the outer bracts much shorter ; this occasionally occurs with a 

 more compound and slender polycephalous panicle. 



A. TRiDENTATA, Nutt. 1. c. Larger, 1 to 6 feet high : leaves cuneate, 3-toothed 

 or 3 lobed at the truncate summit, only the uppermost cuneate-linear and com- 

 monly entire : involucre 5-6-flowered ; its outermost bracts short and ovate, 

 usually tomentose-canescent. Far the most common and wide-spread Sage-brush 

 or Sage-wood. — Var. angdstifolia. Leaves all narrow ; lower spatulate-linear 

 and barely 3-toothed at the rounded ape.x ; upper entire and linear : heads rather 

 smaller, exactly of A. tridentata, while the foliage is nearly that of A. trijida, 

 except tiat it is not trifid. — Arid plains, S. Idaho and W. Nevada to the Mohave 

 Desert and the southern borders of California. 



VOL. XIX. (n. S. XI. ) 4 



