Tetrachjmia. COMPOSIT.^. 4Q- 



Tlie American species are of the Xardosmia section, witli more coiymbose heads an.l .l.-,-i,le,l 

 rays The few species of the group are very nearly rehitcl : tlie most southern one, and the inlv 

 one found in Cahfornia, is the following. But P. saylttala {Xardo.mia, Hook.;, of the liockv 

 Mountains, may possibly occur. ^ v > /, «-">. nuLKy 



1. P. palmata. Clothed with l(jo.se cottony wool when younj--, b(3C(iuiin«r "la- 



hruiis with age : leaves rounded in outline, very deeply 5-7-clell, the lobes iiicis^ly 



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



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



Tussilago palmata, Ait. Kew. etl. 1., iii. 188, t. 2. Nardomiia jmlmata, Hook. " 



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

 fand and Labrador. i. o j o 



98. TETRADYMIA, DC. 



Head 4 -9- (rarely 18-) flowered, homogamous ; the flowers all tubidar and per- 

 fect. Involucre cylindrical or rarely campanulate ; its scales 4, 5, or sometimes 

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

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

 Eeceptacle smaH, flat or nearly so. Corolla with a slender tube, abruptly cUlated 

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

 evident mid-nerve. Anthers exserted, linear, mucronately sagittate, the auricles 

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

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

 or somewhat fusiform, obscurely 5-nerved, long-villous or glabrous. Pappus of 

 copious fine and soft capillary scabrous bristles. — Low and much branched s]iru])s 

 (of the interior arid region, mainly between the Sierra and the Rocky IMountains) ; 

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

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

 Acad. ix. 207. 



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

 stituting the third section. 



§ 1. White-ivooUi/, except the small terete fascicled leaves in the axils of the j^riman/ 

 leccves converted^ into spines : involucre of 5 or 6 scales, 5 - 9-ffowered : bristles 

 of the pcqjpns in a single series, almost equalled and concecde'd by the finer but 

 similar pappus-like long ivhite hairs which densely clothe the akene ! — Lago- 

 THAMNUS, Torr. & Gray. {Lagothamnus, Nutt.) 



1. T. spinosa, Hook. & Am. From 2 to 4 feet high, with rigid divaricate 

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

 leaves crowded in the fascicles, succulent, linear or terete, glabrous (al)out 3 lines 

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

 (half an inch long), sliort-peduncled. — Lagothamnus microphyllus k L. ambiguxs. 



Eastern borders of the State ; San Bernadino Co., on rrovidencc Mountains (Cooper), and 

 through the Nevada desert to Idaho. 



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

 containing four fowers : bristles of the pappus very cojnous : akenes either 

 very villous or in the same species glabrate or glabrous! — Eutetradymia, 

 Torr. & Gray. 



2. T. canescens, DC. A tout oi' two liigh, unannod, silvory-tomentose : leaves 

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



