8 PLANTJE "WKIGHTIAN^. 



length, all repand-toothed or denticulate. Flowering racemes short and dense ; the 

 flowers, &c., much as in T. integrifolium, Etidl. (Pachypodium integrifolium, Nutt. 

 in Torr. 8f Gray, Fl. 1. p. 96), except that the petals are by no means so long ; the 

 fruiting raceme becoming four or five inches in length. Pedicels divaricate in 

 flower and fruit, six lines long. Siliques (immature) slender, two inches long, or 

 nearly, widely spreading. Eipe seeds not seen. In T. integrifolium the pods are 

 only an inch long, and erect or ascending. 



8. Erysimum asperum, DC. ; Hook. Fl. Bor.-Am. 1. p. 64, t. 22; var. siliculis 

 breviusculis adscendentibus. Plains at the western base of the Guadaloupe Moun- 

 tains, El Paso ; Oct. 



9. Sisymbrium auriculatum (sp. nov.) : annuum seu bienne, parce pilosulum ; 

 caule erecto ramose ; foliis lyrato-pinnatifidis subruncinatis petiolatis, caulinis basi 

 auriculis duobus rotundatis stipuliformibus amplexicaulibus instructis, lobis den- 

 tatis triangulatis oblongisve ; racemo virgato fructifero prselongo ; floribus albis 

 majusculis ; sUiquis patentibus teretibus gracilibus stylo brevi manifesto superatis 

 pedicello divaricato quadruple longioribus ; seminibus ovalibus. — Valley of a 

 stream, about ten miles from the Rio Grande, below El Paso ; Sept. — Plant two 

 or three feet high, with somewhat the aspect of S. Irio ; but with less deeply cut 

 leaves, and larger, white flowers. It is especially characterized by the stipuliform 

 auricles at the base of the leaf, remote from the lower of the proper lobes. Flow- 

 ers three lines long, on spreading pedicels of about the same length ; the spatulate 

 petals conspicuous. Raceme in fruit attaining eighteen inches or more in length. 

 Siliques an inch and a half long, slender, widely spreading, or somewhat ascending 

 on the divaricate pedicels : valves 3-nerved, the midnerve more prominent. — 

 Dr. Gregg has the same species from San Antonio de las Alanzanes, Mexico 

 (No. 428 and No. 367) , but with less membranaceous leaves and shorter pods. 



10. S. DiFFUsuM (sp. nov.): perenne, pube 3 - 4-fida minuta canescens ; caulibus 

 ramosissimis diffusis ; ramis usque ad apicem foliosis ; foliis oblongis obtusis basi 

 attenuatis sinuato-dentatis imisve pinnatifidis ; floribus parvis ; petalis calyce brevi- 

 oribus ; sUiquis patentibus teretibus fere subulatis brevibus (4-5 lin. longis) 

 canescentibus stylo manifesto superatis ; seminibus (immaturis) oblongis. — Pass 

 of the Limpia, in crevices of rocks on the mountains ; Aug. — Stems about a 

 foot high, from an elongated and rather ligneous root, much branched, bushy ; the 

 branches and branchlets diverging. Cauline leaves about an inch long, the lower 

 somewhat petioled. Racemes short, branching, often bracteate at the base. Flow- 

 ers minute in all the specimens, with the petals barely discernible ; perhaps they 

 are sometimes more manifest. Siliques scarcely thicker than their pedicels, tipped 

 with a style fully half a line in length. — This species is apparently allied to S. 

 humile of C. A. Meyer, but it certainly is not the plant figured by Ledebour. 



GREGGIA, Nov. Gen. 



Calyx basi sequalis, sepalis lineari-oblongis patentiusculis. Petala obovato-rotun- 

 data, ungue angusto. Discus hypogynus inter petala et stamina annularis, contorto- 

 lobatus, lobis ante stamina. Filamenta edentula, filiformia. Ovarium oblongum a 



