190 UNITED STATES AND MEXICAN BOUNDARY. 
$ II. ZYGOPHYLLEZ. 
EUPHORBIA HEXAGONA, Nutt. in Spreng. Syst. З, р. 791. Е. heterantha, Nutt. in Trans. Amer. 
Phil. бос. (n. ser.) 5, p. 173. Rio Coleto, Texas; Thurber. ‘‘Many years ago Mr. Nuttall 
gave me specimens of this plant, named E. hexagona. Part of these were sent to Sprengel, 
who first published a description of the species in the work quoted." Eight years afterwards 
Mr. N. described the plant under another name. It is remarkable for being polygamous; most 
of the involucres containing only male flowers.” —Torrey, MSS. 
EUPHORBIA BILOBATA (nov. spec ): annua, erecta, gracilis; foliis oppositis breviter petiolatis lan- 
ceolato-linearibus acutatis integris glabriusculis, rameis angustioribus; anthodiis alaribus 
campanulatis; glandulis bilobis, appendiculis binis lanceolatis seu abbreviatis ; stylis vix basi 
connatis ad medium bilobis ; stigmatibus erectis subteretibus ; capsula leviuscula, seminibus 
ovatis acutis angulato-tuberculatis. Near the Copper Mines, New Mexico ; Bige/ w. Eastern 
Sonora; Wright, (No. 1831.) Stems 6-15 inches high; leaves 10-15 lines long, 1- - lines broad; 
seeds 0.8 line long, strongly tuberculate and almost angular. Glands remarkable and very 
constant in shape; appendages white. Near E. hexagona; distinguished by the acuter more 
uniform leaves, bilobed glands, terete stigmata and smaller tuberculate seeds. 
EUPHORBIA BIFURCATA (nov. spec.) : glabra; caule erecto dichotomo ; foliis oppositis ovatis seu 
obovatis in petiolem gracilem subequilongum angustatis argute serratis obtusis basi glanduloso 
stipulatis; anthodiis alaribus breviter pedunculatis ; lobis 5 ovatis truncatis fimbriato-multifidis ; 
glandula singula cyathiformi late albo-appendiculata, appendice transverso emarginato ; stylis 
‘basi coalitis ad medium bifidis, stigmatibus filiformibus. Moist places, Valley of the Limpio, 
July; Bigelow. Over a foot high; leaves 1 inch long, inch wide; petiole a little shorter 
than leaf. 
$ ПІ. СҮАТНОРНОВЖ, 
EUPHORBIA DENTATA, Miche. ; B RIGIDIA : humilior rigida; foliis parvis coriaceis reticulato- 
venosis scabris margine revolutis. Head of San Pedro river; Wright. (No. 1837.) Near 
Monterey, Mexico; Dr. Edwards. ү. СОРНОЗРЕКМА : erecta, stricta, dentata seu parce pilosa ; 
foliis lanceolatis seu lineari-lanceolatis elongatis subdentatis ; capsulis glabris seu pilosis ; semi- 
nibus majoribus tuberculato-angulatis. Copper Mines, New Mexico; Wright, (No. 1834,) to 
Sonora; Schott. Ojo de Gabilari, Chihuahua; Thurber. 
EUPHORBIA HETEROPHYLLA, Linn, (E. cyathophora, Murr.) Var. GRAMINIFOLIA : foliis angusto- 
linearibus. Crevices of rocks and dry beds of rivers. Rio San Pedro, Texas; Bigelow, Schott, 
Wright, (No. 653.) South of El Paso; Wright, (No. 1835.) 
EUPHORBIA BARBELLATA, (nov. spec.): annua, erecta, glabriuscula ; foliis sparsis linearibus seu 
lanceoleto-linearibus seu ovatis lobatisque breviter petiolatis parce argute dentatis, subtus ad 
nervum medium parce pilosis, basi pilis longioribus confertis barbatis; foliis floralibus ovatis 
seu e basi dilatata elongatis, basi roseis; anthodiis glomeratis majusculis ; glandula singula 
sessili lobis inciso-dentatis breviore ; stylis brevibus erectis basi vix connatis ad medium bifidis. 
. On the Rio Grande, near Eagle Pass; Wright. Rio Frio; Bigelow. Near E. heterophylla, but 
stouter, leaves very sharply serrate, involucre larger, styles shorter. Leaves 2—4 inches long, 
4 or $ іпеһ-1 or 2 lines wide. Beard of coarse hair at base of leaves very conspicuous. 
EUPHORBIA COLORATA (nov. spec.): erecta, glaberrima ; foliis breviter petiolatis sparsis patu- 
