226 UNITED STATES AND MEXICAN BOUNDARY. 



petals ; filaments bearded witli wliite hairs ; cells of the anthers reniform^ separated by a broad 



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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 d^varf state of T. rosea, but our specimens are too imperfect for satisfactory 



comparison. 



CYPEKACEAE. 



Cyperus DIANDEUS, ToTT. Gat. PI. N. Yorkj p. 90, <& Gyp. p. 251, Western Texas; Wright^ 



(No. 1749.) 



Cypeeus flavicomus, Michx. Fl. 1^ p. 27 ; Torr. I. c. p. 253. Sonera, Mexico ; Thurler, 

 (No. 1965^ Wright.^ Our specimens are smaller than the usual form of this species, and the 

 umbel is 2-4-rajed ; but in other respects there is no essential difference. 



Cyperus jviicrodontus, Torr. p. 255. C. Gatesii, Torr. I, c. Western Texas ; Wright n A 

 comparison of specimens from numerous localities shows the necessity of uniting these two 

 species. 



Cyperus articulatus, Linn. ; Torr. I. c.p. 256. Western Texas ; Wright. 



Cyperus laterieloeus (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 

 sub^equali; stylo trifido. Along mountain torrents^ east of Santa Cruz, Sonora; Wright^ (No. 

 1950.) Annual. Culms csespitosC; 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. Eachis very narrow and zigzag, slightly margined. Allied to C. fuscus 

 of Europe. 



Cyperus Michauxianus^ Schultes, Mant. 2, p. 123 ; Torr. Gyp. p. 259. "Wet places, western 

 Texas and New Mexico^ westward to the Colorado. No. 1946, Wright, is a dwarf variety. C. 



which 

 form ( 



are furnished with conspicuous involucels. 



Ell. Sk. 1, p. 71; Torr. Gyp. p. 261. Santa Cruz, Sonora; Thurher. 



Mono 



from 



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 q^uadrangular, 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, 



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