CATALOGUE. 189 



lower part of the: rootstock decaying, the remaining part throws out 



annually numerous strong fibres. The root of A. Mexicana ought to be 



compared with it. 



GENTIANE^. 



By De. George Engelmann. 



Erythr2EA calycosa, Buckley; Gray, Synops. 113. — Simple or branch- 

 ing from an annual or biennial base ; erect stems quadrangular- winged; 

 leaves linear-lanceolate (about V long), lower ones broader, as long or longer 

 than the internodes; panicle rather contracted, loose-flowered; pedicels as 

 long as or longer (or the upper ones shorter) than the large flowers (8-10" 

 in diameter, rose-colored, with yellow centre) ; calyx about the length of 

 the flower-tube; lobes of corolla oblong, acutish, often denticulate, scarcely 

 shorter than their tube ; seeds small, 0.3-0. 4 mm long. 



In the Gila Valley, Rothrock, 1874 (325), and southeastward into 

 Mexico, Gregg, etc. — Stems 1—1 £° high, the tallest of our species; leaves 

 l-l£' long, distinguished by its large bi- or tri-colored flowers with acutish 

 lobes. -E. venusta, Gray, with which it has been confounded, is a smaller 

 plant with larger deeper-colored flowers, broader obtuse corolla-lobes, and 

 usually longer anthers and larger seeds. — The anthers of the different species 

 of JSrythrma are of different shape and size, from orbicular and oval to oblong 

 and linear and £-4 or 5 mm in length ; all become at last spirally twisted 

 after they have shed their pollen, the longer more conspicuously so, the 

 shorter much less. The stigmas of this gentts have often been misunder- 

 stood, probably because mostly observed in dried and pressed specimens. 

 They are never capitate or funnel-shaped, but always bilobed. Before 

 maturity, they remain closed, and only after the anthers have shed their 

 pollen do both halves separate and spread out, just as the Gentians behave. 

 In the form of the stigma, I find valuable characters for grouping of the 

 species, and especially for the distinction of the American ones from those 

 of the Old World. The stigmas of the former are flabelliform and broader 

 than long ; those of the latter are orbicular-ovate or oblong to linear ; 

 shortest in E. spicata and linearifolia, and longest in major, where they are 

 twice as long as wide, and in maritima, in which the length is 3 or 4 times 



