98 A. Gray on a new genus of Verbenacea. 
are opposite, and the stamens are only four in number. The lat- 
ter characters, along with the quadrinuculate fruit, and the axillary 
cymulose inflorescence, would incline us to refer the plant to the 
order Labiate ; which again is forbidden by the regular corolla, 
the apparently equal stamens, and the amphitropous descending 
ovule. ‘The latter character points to the true aflinity of the 
genus, which unquestionably should be placed in the Viticeous 
division of the order Verbenacee ; notwithstanding the deeply 
four-lobed ovary, and the fruit of four nucules. ‘This remarkable 
character may well furnish the name of the genus ;—which I 
accordingly form of térga, four, and xielo, to close or shut up, re 
ferring ro the four closed nutlets of the fruit. 
TETRACLEA, Nov. Gen. 
Calyx profunde quinquefidus, tubo turbinato, lobis subsequali- 
bus. Corolla hypocraterimorpha, tubo calyce longiore, limbo 
quinquepartito, lobis obovatis fere equalibus. Stamina 4, fauci 
corollz inserta: filamenta filiformia, equilonga, exserta, in ala- 
bastro involuta: antherze ovales, loculis parallelis. Ovarium pro- 
funde quadrilobum : stylus filiformis apice bifidus: stigmata sub- 
ulata. Ovula in loculis solitaria, amphitropa, pendula; micropyle 
infera. Fructus quadrinuculatus, calyce persistente immutato cinc- 
tus; nuculis siccis obovatis reticulatis crustaceis. Semen loculo 
conforme, subcurvatum, supra medium appensum, exalbumino- 
sum. mbryo leviter incurvum; cotyledonibus ovalibus crassi- 
usculis ; radicula brevi infera——Herba erecta, hnmilis, e basi suf- 
frutescente ; foliis oppositis petiolatis ovatis subdentatis; floribus 
in axillis cymulosis sepius ternis majusculis; corolla alba post 
anthesin flavescente. 
Terractea Counrert—Mexico, Dr. Coulter (No. 1172, in 
coll.).—Prairies of San Felipe and Live Oak Creeks, ‘T'exas, 
Wright, 1849 (No, 462); also at Escondido Springs, in the 
same district, 1852. Azufrora, near Saltillo, Mexico, Dr. Gregg 
(No. 502). Saur de Cienega, between Conde’s Camp and the 
Chiricahui Mountains, on the borders of New Mexico and Sonora, 
Wright, 1851 (No. 1513). 
The other Verbenaceous plants of Mr. Wright’s collection which 
appear to be new are Bouchea linifolia, sp. nov. (No, 449 a 
1509), and Lippia (Aloysia) Wrightii (No. 1506)), a species 
allied to L. scorodonioides, 
