in the third group are scapigerous, but the peduncle is more or less leafy and the flowers racemose, the radical leaves are distinct from the cauline. The last division differs from the former only in for min g shrubs, the branches being leafy throughout their length, an artificial character, but sufficiently available so far as the included species are concerned.
17. D. Tohuscetms, H. B. K., Nov. Gen. et Sp. Plant. Am. vol. v. p. 73.
Hab. Mexico; Humboldt and Bonpland. Oaxaca, 12,000-13,000 feet ; Galeotti.
18. D. Jorullensis, H.B.K., I.e.
Hab. Mexico; Jorullo; Humboldt and Bonpland.
An hujus seetionis ?
§ TV. Fruticulosa, caule e bad ramoso, ramisfoliosis, foliis radicalibus a caulinis rum distinguendis.
19. D. violacea, DC. ; D. Bonplandiana, H. B. K., 1. c.
Hab. Colombia; Assuay, 13,000-14,000 feet; Humboldt and Bonpland, Professor Jameson.
Fndiculus pedalis. Flores subcorymbosi, magnitudine et colore variabiles. PediceUi fructiferi silicula breviores.
Silicula lineari-ovatee, incano-tomentosae, in stylum gracilem gradatim attenuate. Semina plurima, obloriga, atro-
fusca.
20. D. alyssoides, H. B. K., 1. c. non Benth. Plant. Hartweg. Hook, et Am. Bot. Hisceil. vol. i. p. 126. t. 32.
Hab. Colombia; Province of Pasto ; Humboldt and Bonpland. Summit of Pichincha and Pillzhum ; Professor Jameson.
Flores albi, ampli. Silicula longiores stylique breviores quam in praecedente. Semina parva.
I have retained the name given to this plant in the ' Botanical Miscellany,' (vol. iii. p. 137), and also so called by Professor Jameson. Mr. Bentham has considered my D. Hallii as the D. alyssoides of Humboldt and Bonpland, whose specific character does not allow of my deciding the question.
21. D. Hallii, n. sp. ; fruticulosa, ramosa, incano-pubescens, foliis radicalibus nullis caulinis sessilibus lineari-oblongis oblongo-obovatisve remote dentatis supra sericeo-hirsutis subtus stellatim tomentosis, racemis elongatis, florilms amplis albidis, pedicellis basi bracteatis fi-uctiferis erecto-patentibus silicula brevioribus, siliculis lineari-oblongis in stylum brevem attenuatis, valvis planiuseulis pubescentibus, seminibus plurimis majusculis. D. alyssoides, Benth. Plant. Hartweg. p. 159. n. 884.
Hab. Colombia ; Chimborazo, Pichincha, and Antisana, near the snow limit ; Col. Hall, Professor Jameson, Hartweg.
Pedalis et ultra, vage ramosa, caulibus basi nudis. Folia 1-2 uncialia. Silicula forma variae, pleraeque unc. longse, liueari- v w ovato-oblongae, glabriusculae, iuterdum lineares et f unc. longa?.
22. D. Arbuscula, n. sp. ; fruticulosa, stellatim pubescens, ramosa, raniis adscendentibus inferne lignosis nudis superne foHosis, foliis parvis imbrieatis obovatis obtusis, petiolis vaginantibus dilatatis glaberrimis, floribus flavis, siliculis pedicello brevioribus adscendentibus anguste elliptico-ovatis in stylum brevem attenuatis, valvis planis glabriuscuhs, semimbus plurimis majusculis.
Hab. Caraccas; Linden (n. 439).
Caulis basi crassitie pennae anatinae, superne in ramos plurimos adscendentes fastigiatos divisus. Rami basi nudi, foliis delapsis cicatricati ; ramulis 2-3 imcialibus, foliosis. Folia unc. longa, imbricata, ovata, in petiolum
