Tftrmhjmln. COMPOSITJC. 407 



'I'lin AiMciican apecioa me of tlio Nardosmin section, willi iiioic coryml'ose lieads and rlecidiMl 

 vnys. Tlio low species of the group are very nearly related : the most southern one, and the only 

 one found in C'alifoniia, is the following. Hut P. sagitlaUt {Aardo.iniia, Hook.), of the Ilocky 

 Mountains, may i>ossibly occur. 



1. P. palmata. Clothed with loose cottony wool when young, becoming gla- 

 brous with age : leaves rounded in outline, very deeply 5-7-ck'it, the lobes incisely 

 toothed or lobed : flowers dull white, deliciously scented : rays in the sterile heads 

 oblong and conspicuous, in the fertile ones narrow and shorter than their style. — 

 tnssilaijn palmata, Ait. Kew. oil. 1., iii. 188, t. 2. Nanln.vnia palmafa, Ilook. 



Damp woodlands, from San Francisco northward. Also in Oregon and sparingly to New Eng- 

 land and Ijabrador. 



98. TETRADYMIA, DC. 



Head 4 - 9- (rarely 18-) llowercd, honiogaiuous ; the flowers all tubular and per- 

 fect. Involucre cylindrical or rarely cainpanulate ; its scales 4, 6, or sometimes 

 more numerous, oblong or narrower, rather rigid, more or less concave and carinatc, 

 nearly equal, in one or two series, and rarely with short external ones at the base. 

 Receptacle small, flat or nearly so. Corolla with a slender tube, abruptly dilated 

 into a 5-partcd limb ; the lobes linear or lanceolate, traversed by a more or less 

 evident mid-nerve. Anthers cxserted, linear, raucronately sagittate, the auricles 

 connate. Style-branches with minutely penicillato apex tipped with a very short 

 and obtuse or sometimes more conspicuous and acute cone. Akenes terete, oblong 

 or somewhat fusiform, obscurely H-nerved, long-villous or glabrous. Pappus of 

 copious fine and soft capillary scabrous bristles. — Low and much branched shrubs 

 (of the interior arid region, mainly between the Sierra and the Tiocky ^fountains) ; 

 with alternate linear or subulate entire leaves, and corymbose or racemose clusters 

 of middle-sized heads : corollas yellow. — DC. Vwdr. vi. 240 ; Gmy, Proc. Am. 

 Acad. ix. 207. 



In the paper above cited, the genus is extended so as to include an ambiguous spcics, con- 

 stituting the third section. 



§ 1. W/iite-woolli/, except the nmall terete fascicled leaves in the axils nf the jn-imari/ 

 leaves converted into spines : involucre of 5 or G scales, f) - ^d-Jlowered : bristles 

 of the pappus in a single series, almost equalled and concealed by the finer but 

 similar pappus-like long tvhite hairs which densely clothe the ak^ne ! — Lago- 

 TIIAMNU9, Torr. (fe Gray. (Lar/othamnus, Nutt.) 



1. T. spinosa, Hook. <fe Arn. From 2 to 4 feet high, with rigid divaricnto 

 branches, clothed with dense white wool and armed with sharp slonder spines : 

 leaves crowded in the fascicles, succulent, linear or terete, glabrous (about 3 lines 

 long), mostly shorter than the spines : heads racemose or scattered along the bmnches 

 (half an incli long), short-peduncled. — Lacjotliamnus microphyllns k L. ambicjuns, 

 Nutt. 



Eastern borders of the State ; San Bornadino Co., on Providence iMountains {Cooper), and 

 through the Nevada desert to Idaho. 



§ 2. White-woolly, or sometimes almost glahrate : involucre of 4 or 5 concave scales 

 containing four flowers : bristles of the pappus very copious : akenes either 

 very villous or in the same species glabrate or glabrous/ Imitictiiahymia, 

 Torr. (^ Cray. 



2. T. canescens, DC. A foot or two high, unarmed, silvery-tomontoso : loaves 

 narrowly linear, varying to linear-lanceolate or somewhat spatulnto (and from an 



