OF ARTS AXD SCIENCES. 199 



Bentham, as also Achyropappus IIBK. The North Americau species 

 are characterized below.* I have to add a peculiar perennial species. 



* § 1. ScHKUHRiA VERA. Capituluiii pauciflorum : involucrum turbinatum vel in 



sicco pyraniidatum, e squamis 4-5 obovatis apice sphacelato coloratis : ligulse 

 1-2 brevissimaj imperfectae : achenia obpyraraidato-tetragona. Folia vel seg- 

 nienta fere filiformia. 



1. S. HoPKiRKiA Gray, PI. Wright, 2, p. 94. Eaniosissima ; capitulis 3-4- 

 floris ; ligula unica nunc nulla ; acheniis ad angulos villosissimis faciebus triner- 

 vatis ; pappi paleis 8 conformibus ovatis coroUam tequantibus nervo valido 

 excurrente aristellatis. — Hopkirkia anthemoidea DC. — Southern borders of 

 Arizona, C. Wright, and Mexico. 



2. S. Wrightii Gray, I.e. Gracilis; capitulis 3-5floris; ligula unica; acheniis 

 prajcedentis sed minus crassis; pappi paleis 8 conformibus obovatis muticis basi 

 tantum incrassatis corolla pauUo brevioribus. — Southern borders of Arizona, 

 near Santa Cruz, Sonora. 



§ 2. Achyropappus. Capitulum pluri-multiflorum : involucrum srepius hemt- 

 sphaericum: ligulae 5-12 exsertse, raro nullaj : corolla limbo magis ampliato. 

 (Achenia in nostris attenuata.) 



* Ramosissima, graciUima, glabella ; foliorum segmentis angustissime linearibus 



integerrimis : pappi palea3 8 obovatse, muticae, prseter basim incrassatam 

 opacam enervice. 



3. S. Neo-Mexicana Gray, PI. Fendl. p. 96. Spithamaja ; pedunculis brevius- 

 culis subpaniculatis ; ligulis nullis ; pappo coroUam subaequante. — Santa Pe, 

 &c.. New Mexico. 



4. S. BiGELOvii. Ultrapedalis; foliis caulinisplerisqueoppositis; pedunculis 

 elongatis filitbrraibus ; ligulis 8-9 oblongis ; pappo tube corollaj disci brevioi'e. — 

 Bahia {Achip-opappus) Bigehvii Gray, in Bot. Mex. Bound, p. 96. 



* * Ramosa, humilis; foliis plerisque oppositis pinnato-3-5-partitis, segmentis 



linearibus : pappi palese 8-9 lanceolatae, costa valida percursse : achenia vix 

 angulata. 



5. S. WooDHonsEi. Achyropappus Woodhousei Gray, Proc. Am. Acad. 6, p. 

 546. — New Mexico, Dr. Woodhouse. 



* * * Pedalis ad bipedalera, cinereo-puberula ; foliis alternis pedati- vel palmati- 



sectis ; capitulis in caule apice nudo corymbosis : pappus e paleis 10-14. 



6. S. pedata. Poliorum segmentis obovatis vel cuneato-oblongis ; pappi 

 paleis obovatis retusis, costa valida infra apicem evanida. — Bahia pedata Gray, 

 PI. Wright, 1, p. 123. — Western borders of Texas, &c. 



7. S. biternata. Foliorum segmentis linearibus ; pappi paleis lineari-lanceo- 

 latis costa excurrente aristatis achenio subajquilongis, vel in tl. extimis latioribus 

 muticis. — Bahia biternata Gray, PI. Wright, 2, p. 95. — New Mexico. 



§ 3. Plattschkuhria. Capitulum floresque Achyropappi, habitu proprio, ra- 

 dice perenni etc. ut in char, specif. 



8. S. INTEGRIFOLIA. Ciuereo-puberula, nunc glabrata ; caulibus floriferis e 

 caudice multicipiti erectis spithamaais ssepius scapiformibus basi tantum foliosis 



