OF ARTS AND SCIENCES : JUNE 14, 1870. 253 



++ Brevissima, latiuscula vel squamiformia, imbricata, mollia, tan- 

 tum raucronata. Plantas pulvinatae musciformes ; corollas lobi 

 integerrimi. 



13. P. Richakdsonii, Hook. Fl. 2, p. 73, t. 160. Laxius pulvi- 

 nata ; foliis oblongo-lanceolatis (lin. 3 longis) parcius lanigeris margini- 

 bus incrassatis raox reflexis imbricatis, vetustis laxe patentibus ; corollas 

 " laste lilacinas," tubo calycem dimidio excedente, lobis late cuneato- 

 obovatis lin. 3 longis. — Arctic sea-sbore. 



14. P. brtoides, Nutt. PL Gamb. p. 153. Densius pulvinata, mini- 

 ma, facie Selaginellam rvpestrem referens, copiose mollissime lanata ; 

 ramulis discretis ; foliis arete quadrifariam imbricatis squamasformibus 

 ovato- seu triangulari-lanceolatis (sesquilineam longis) etiam marces- 

 centibus creberrime appressis, marginibus subinflexis ; corollas tubo 

 calycem modice superante, lobis cuneatis sesquilineam longis. — Di- 

 viding ridge of the Rocky Mountains (about lat. 42°), Nuttall. 



15. P. jiuscoides, Nutt. Jour. Acad. Philad. 7, p. 42, t. 6, p. 2 

 Prascedenti similis, Bryum aliquid canescens referens ; ramis brevibus 

 confertissimis ; foliis minus stricte quadrifariis parcius lanatis ovato- 

 lanceolatis parum mucronulatis (sesquilineam longis) ; corollas tubo 

 calycem baud superante. — Rocky Mountains at the sources of the 

 Missouri River, Wyeth. 



-t-t- -H- Folia rigidiora, subulata, subacerosa (lin. 3-4 longa), minus 

 appresso-imbricata. Plantas late casspitantes, corollis ut videtur 

 albis. 



16. P. Hoodu, Richards. Appx. t. 28. Parcius lanata, glabrata; 

 foliis erectis ; corollas tubo calycem baud superante, lobis obovatis in- 

 tegris, 2-2- 1 - lin. longis. — Through the Saskatchavvan region from lat. 

 54° to the Rocky Mountains about lat. 44°. 



17. P. canescens, Torr. & Gray, Pacif. R. R. 2, p. 8, t. 6. Magis 

 lanata, canescens ; foliis e basi appressa mox patentibus vel subsquarroso- 

 recurvis ; corollas tubo calycem pi. m. saspius dimidio superante, lobis 

 obovatis integris vel emarginatis lin. 3-4 longis. — Rocky Mountains 

 of Colorado and throughout Utah to New Mexico and the Sierra 

 Nevada. 



h— -i— Folia rigidiora marginibus basi saltern hirsuto- vel hirtello- 

 ciliata, nunc nuda. 



18. P. c^spitosa, Nutt. 1. c. t. 6, f. 1. Dense seu laxiuscule cass- 

 pitosa ; foliis rigidis lineari-subulatis seu oblongo-linearibus (lin. 4-6 



