166 MR. NUTTALL’S DESCRIPTIONS OF NEW 
length, almost disposed in a simple series; the achenium is also lanuginous, and the 
seed presents, as in E. tomentosum, a concentric embryo. For £. longifolium I 
would therefore propose the name of TracuyTHECA, excluding every other species. 
It is the first species of the section Er1ANTHA of Bentham, which name, in not being 
exclusive, and too near Erianthus, cannot properly be employed for the present plant. 
It is very peculiar in its solitary leaves and alternate branches. 
In all the rest of this numerous genus, the outer segments of the perianth, which 
increase a little in size, are either larger and erect, or all nearly equal. In these, 
some of which have the embryo excentric and others concentric, the subgeneric name 
of OLycoconuM may be applied, but whether any other subdivision may be made by 
the condition of the embryo is at present uncertain. In E. flavum I believe the 
embryo is excentric, but how far that species connects itself to any others of similar 
form, remains to be examined. 
*EUCYCLA.T 
Perianth membranaceous, coloured, petaloid, dimorphous, the three outer divisions 
orbicular, concave; the three inner linear-oblong, emarginate, connivent into a 
cylinder. Stamens nine; with short filaments, membranous at base. Styles three, 
of moderate length, with small, capitate stigmas. Achenium attenuated, triangular. 
Embryo excentric; radicle superior; cotyledons flat. 
E. *ovAtiror1a.—Leaves all radical, short and roundish-ovate, whitely tomentose; capitulum made up of 
several sessile, whitely tomentose involucres; outer segments of the yellow perianth rather narrower 
at base, the inner emarginate segments exserted. 
Erigonum ovalifolium. Nutt. Journ. Acad. Nat. Sci., Philad. 
Has. Sources of the Missouri. Flowers bright yellow. 
E. *purpurea. Leaves all radical, short and roundish-ovate, whitely tomentose; capitulum made up of 
several sessile, smoothish, tomentosely margined involucres; outer segments of the purple perianth 
orbicular, sometimes emarginate at base; the inner emarginate, narrow, segments scarcely exserted. 
Scape about a span high, arising from a multifid woody caudex; flower larger than 
in the preceding, and purple; filaments much shorter than the perianth, with a torn 
membranous margin, at base three stamens seated on each of the inner narrow 
segments; embryo rather short. 
Has. Rocky Mountains. 
. CHORIZANTHE. 
C. *nupicaute. Annual; radical leaves narrow spathulate, pubescent, with long, slender petioles, 
tomentose beneath; scapiform stem nearly naked, the summit trichotomous, the branchlets once or 
twice bifid, the flowers cymosely conglomerated; stem and very unequal toothed involucrum 
lanuginous; segments of the sessile exserted, perianth oblong, obtuse. 
t In reference to the circular figure of the perianth. 
