PLANTS COLLECTED BY DR. GAMBEL. 169 



smooth and wiry, rigidly horizontal, at the first or second joint, bearing a few leaves below the 

 capitulum, the joints not deciduous ; heads of flowers about the size of peas, bearing ten or more 

 flowers each, subtended with, and mixed up with the elliptic bractes, which are margined and smooth 

 beneath, densely woolly like the leaves of some Gnaphalium above ; perianth exserted a little on a 

 jointed peduncle, brownish, with white margins to the oval obtuse segments ; some flowers appear to 

 be hermaphrodite, others with stamens only. 



Hab. St. Diego, Upper California, in sandy places, near to the sea shore. 

 Flowering in April and May. (Nuttall.) 



N. *FOLiosA. With the above, from which it perhaps is not distinct ; the leaves are much loncrer, the 

 stem a little glutinous, and with most of the joints of the latter leafy. 



*OXYTHECA.t 



Dioicous or monoicous. Involucrum small, four to five-toothed, obconic, few- 

 flowered, (three to five,) the teeth mostly spinulose. Female perianth closed to the 

 summit, about six-toothed ; male and hermaphrodite shortly six-cleft. Stamens 

 about six? Achenium compressed, two-sided, elliptic. Style three. Embryo 

 excentric, in a somewhat fleshy perisperm, antitropus. Cotyledones oval, flat; 

 radicle elongated, curved. — Annuals, with the leaves generally hirsute, nearly all 

 radical ; panicle or branches trichotomous and very divaricate, the ramifications 

 subtended by verticillated bractes, free or united, into a cup. Involucres very small, 

 solitary and pedicellate, four to five-toothed, the teeth terminating in very lono-, 

 sharp, rigid bristles, more rarely unarmed ; perianth pubescent ; the branches clothed 

 with viscid, pedicellate glands. Somewhat allied to Chorizanthe, but with the 

 involucrum more than one-flowered, and the achenium compressed. 



O. *DENDROiDEA. Lcaves all linear, radical, hirsute ; scape divaricately di- and trichotomous; peduncles 

 capillary ; involucrum about three-flowered ; awns twice the length of the involucrum. 



A slender annual, about four to six inches high ; the leaves in a rosulate cluster, 

 imbricated round the caudex ; about one to one and a half inches long, and' less than 

 a line wide ; very hirsute, and strongly revolute ; the bractes at the divisions of the 

 stem divided at the base ; about three flowers in an involucrum ; perianth of the 

 female flower pubescent, nearly entire, and closed around the achenium to its summit, 

 which slightly projects, purplish at the point, exserted from the involucrum ; achenium 

 compressed, lenticular, strongly adhering to the perianth, with a projecting triangular 

 summit ; styles three, very slender, and rather short. 



Hab. On the sand hills of the Rocky Mountains, near Lewis' River. 



0. *FOLiosA. Leaves linear-lanceolate, hirsute ; divisions of the trichotomous stem subtended by verticils 

 of leaves ; awns of the involucrum about its length. 



t In allusion to the peculiar involucrum. 



