226 UNITED STATES AND MEXICAN BOUNDARY. 
petals ; filaments bearded with white hairs ; cells of the anthers reniform, separated by a broad 
connective. Style filiform ; stigma peltate-capitate. This species resembles T. rosea, but differs 
in the smooth sheaths, compound umbel, etc. No. 701 of Mr. Wright’s Texan collection (1849) 
seems to be a dwarf state of T. rosea, but our specimens are too imperfect for satisfactory 
comparison. 
CYPERACEAE. 
CYPERUS DIANDRUS, Torr. Cat. Pl. N. York, p. 90, Ф Сур. p. 251. Western Texas; Wright, 
(No. 1749.) 
CYPERUS FLAVICOMUS, Miche. Fl. 1, р. 27; Torr. 1. c. p. 253. Sonora, Mexico; Thurber. 
(No. 1965, Wright.) Our specimens are smaller than the usual form of this species, and the 
umbel is 2—4-rayed ; but in other respects there is no essential difference. 
CYPERUS MICRODONTUS, Torr. p. 255. С. Gatesii, Torr. l. c. Western Texas; Wright. А 
comparison of specimens from numerous localities shows the necessity of uniting these two 
species. 
CYPERUS ARTICULATUS, Linn. ; Torr. l. c. p. 256. Western Texas; Wright. 
CYPERUS LATERIFLORUS (n. sp.): umbella capitato-contracta quasi laterali ; involucro diphyllo, 
foliolis valde inequalibus, uno longissimo erecto culmum desinente ; spiculis confertis linearibus 
12-20-floris; squamis parum remotis suborbiculari-ovatis obtusissimis (ferrugineis) obscure 
trinerviis; floribus diandris; achenio obovato triquetro pallido scabriusculo nitidulo squama 
subzquali; stylo trifido. Along mountain torrents, east of Santa Cruz, Sonora; Wright, (No. 
1950.) Annual. Culms cespitose, about three inches high, triangular, slightly rough on the 
angles. Leaves shorter than the culm, rough on the margin. Involucre of 2 very unequal leaves ; 
one of the leaves nearly as long as the culm, of which it appears to be a continuation, the other 
scarcely one fourth as long. Umbel somewhat capitate and apparently lateral, sometimes with 
a single short ray. Spikelets 2—3 lines long. Scales light brown on the sides with a pale narrow 
margin and keel. Rachis very narrow and zigzag, slightly margined. Allied to C. fuscus 
of Europe. 
CYPERUS MICHAUXIANUS, Schultes, Mant. 2, p. 123 ; Torr. Cyp. p. 259. Wet places, western 
Texas and New Mexico, westward to the Colorado. No. 1946, Wright, is a dwarf variety. C. 
speciosus, Vahl, or at least of Torr. Cyp., of which we have Californian specimens collected by 
Rev. A. Fitch, is, perhaps, only a luxuriant form of this species, in which the partial umbels 
are furnished with conspicuous involucels. 
CYPERUS TETRAGONUS, ЕЙ. Sk. 1, p. Т1; Torr. Сур. p. 261. Santa Cruz, Sonora; Thurber. 
Since this plant was noticed in the Monograph of North American Сурегасеге, I have seen the 
original specimens of Elliott, and have also received it from east Florida, Louisiana, and Texas. 
The umbel consists of 4-10 somewhat spreading rays, each bearing a narrowly oblong spike an 
inch or more in length. The spikes are either simple or they produce 1-3 smaller ones at the 
base. Spikelets very numerous, obtuse and somewhat quadrangular, crowded on the rachis and 
spreading horizontally, (or the lower ones reflexed,) about 2 lines long, usually perfecting 2 or 
3 achenia. Scales oblong, rather obtuse, light brown on the sides, with a narrow stripe along 
the obtuse keel. Stamens 3. Style deeply 3-cleft. Achenium oblong, triangular, dull, 
