OF ARTS AND SCIENCES : JUNE 11, 1867. 363 



Arnica parviflora : breviter pubescens, multicaulis ; foliis inas- 

 qualiter dentatis, inferioribus subcordatis longe petiolatis, superioribus 

 parvis sa?pe alternis syblanceolatis spathulatisve in petiolum margina- 

 tum angustatis, sensim in bracteis transeuntibus ; capitulis plurimis 

 paniculatis pro genere parvis ; ligulis nullis ; acheniis minutim glandu- 

 losis glabris. — Humboldt Co., in tbe northern part of California, in 

 thickets, Bolander. Rootstocks slender and branching. Stems a foot 

 high, slender. Radical and lower leaves 1 to 2 inches long, on petioles 

 of 1^ to 3 inches in length. Heads 6 or 7 lines long, on rather slender 

 peduncles. Involucre slightly pubescent, of about 12 scales; the 

 flowers 20 to 30. Rays wanting in all the specimens. Achenia only 

 2 lines long. 



Psathyrotes annua: Gray, PL Wright. 2, p. 100, non PI. Thurb. 

 p. 323, &c. Mono Lake, Bolander. [Also on sterile saline plains, 

 Humboldt, Humboldt Co., Nevada, Dr. Torrey.] — Here, at length, we 

 have good and abundant specimens of Nuttall's plant, the Bulbostylis 

 (Psathyrotus) annua of PI. Gambel. ; with which, in the lack of suffi- 

 cient materials, I had confounded a related but distinct species. The 

 character of the genus moreover needing some correction, a revision is 

 offered in the appended note.* 



* PSATHYROTES, Gray, PI. Wright. 2, p. 100. 



Capitulum homogamum, nmltiflorum. Involucrum circ. biseriale; squamis 

 disco sabsequalibus. Receptaculum convexum vel planum, nudum. Corollas e 

 tubo proprio brevi.ssimo cylindricse, apice 5-dentatas, dentibus brevibus latis extus 

 villosis. Stamina prope basim corollas inserta : antherae elongatas, e caudatas, in- 

 elusse, demum semi-exsertas. Styli rami compressi, capitellato-truncati vel obtusi. 

 Achenia turhinata vel oblonga, villosa. Pappus pilosus, corolla brevior, setis 

 rigidulis inasqualibus (vix sen levissime serrelalis). Herbaj parvulas, depressae, 

 nionocarpieas, subviscosas, odore balsamico graveolentes ; foliis alternis dilatatis 

 petiolatis ; floribus luteis. 



§ 1. Ramosissimas, foliosas ; foliis Atrvplids facie longc petiolatis; capitulis alari- 

 bus et subcorymbosis breviter pedunculatis post anthesin nutantibus. Involucri 

 squamae 5 exteriores persistentes ; casteras tenuiores, subscariosae, trinerves, cum 

 florilius 16 - 20 deciduae. Corollas angustas, apice lana longa implexa arachnoideas. 

 Styli rami breviusculi, apice subcapitellato-truncati. Achenia villosissima, pilis 

 rigidiusculis summo apice plerisque (ut a Torreyo dicitur) bifidis. 



P. ramosissima : albo-tomen'osa ; foliis rotundatis parce crenatis ; involucri 

 squamis oblongis obtusis, 5 exterioribus latioribus obtusissimis ; floribus saturate 

 flavis ; acheniis breviter turbinatis; pappi setis pluriserialibus valde inasqualibus. 

 Tetradymia (Polydymia) ramosissima, Torr. in Emory, Rep. (1848) p. 145. Psathy- 

 rotes annua, Gray, in PI. Thurb. p. 323, & Mex. Bound. Surv. p. 102, quoad PI. 

 Thurb., Emory, etc. 



