[ 174 



96 



widely diffused in the barren regions towards the Rocky mountains. It belongs to the sub-order 

 spirolobesc of Meyer and Mocquin, but can hardly be referred to either the tribe suxdince or to 

 sulsolae, differing from both in its diclinous heteromorphous flowers, and also from the latter in its 

 flat-spiral, not cochleate embryo. 



NYCTAGINACE^. 



Oxybaphus nyctagineu, (Torr. in James's Rocky Mountain Plants.) Calymenia nyctaginea, 

 (Nutt.) Kansas river, June 20. 



Abronia mellifera, (Dougl ) North fork of the Platte, July 7-12. 



A. (tripteroealyx) micranthum, n. sp. Viscid and glandularly pubescent; leaves ovate, undulate, 

 obtuse, acute at the base, petiolatc; perianth funnel form, 4-lobed at the summit, 3 to 4 androus; 

 achenium broadly 3-winged. — Near the mouth of Sweet Water river. August 1. Annual. 

 Stem diffusely branched from the base, beginning to flower when only an inch high; the branches 

 of the mature plant above a foot long. Leaves 1 to U inch in length; petioles about as long 

 as the lamina. Heads axillary. Involucre 5-leaved, 8 to 14 -flowered; leaflets ovate, acumi- 

 nate. Perianth colored, (purplish,) 3 to 4 lines long; lobes semi-ovate, obtuse. Stamens inserted 

 in the middle of the tube, unequal; anthers ovate, sagittate at the base. Ovary oblong, clothed 

 with the 3-winged base of the calyx; style filiform; stigma filiform -clavate, incurved. Mature 

 achenium about 7 lines long and 4 wide; the wings broad, nearly equal, membranaceous and 

 strongly reticulated. Seed oblong. Embryo conduplicate, involving the deeply 2-parted mealy 

 albumen; radicle linear-terete; inner cotyledon abortive! outer one oblong, foliaceous, concave, 

 as long as the radicle. This interesiing plant differs from its congeners in its funnel-form pe- 

 rianth, 3 to 4 androus flowers, and broadly 3-winged fruit, but I have not been able to compare 

 it critically with other species of abronia. It may prove to be a distinct genus. 



POLYGONACE^E. 



Polygonum Persicaria, (Linn.) North fork of the Platte. September 4. 



P. aviculare, (Linn.) With the preceding. 



P. amphibium, (Linn.) Sweet Water river. August 4. 



P. viviparum, (Linn.) Black hills. July 26. 



Rumex salicifulius, ( Weinn. ) With the preceding. 



Oxyria reniformis, (Hill.) Alpine region of the Wind river mountains. August 13-16. 



Eriogonum ovalifolium, (Nutt.) Horse-shoe creek, Upper North fork of the Platte. July 22. 



E. ccespitosum, (Nutt.) With the preceding. 



E. umbellatum, (Torr., ) in Ann. Lye. Nat. Hist. N. York, ii,'p. 241. Sweet Water river, Aug. 7. 



E. Fremonlii, n. sp. With the preceding. 



E. annuum, (Nutt.) North fork of the Platte. September 4. 



ELEAGNACE.E. 

 ■Shepherdia urgentea, (Nutt.) " Grains de bceuf.'' Upper North fork of the Platte, from the 



Red Buttes to the mouth of the Sweet Water. August 2i-28. 

 •S. Canadensis, (Nutt.) On a lake in the Wind river mountains. August 12-17. 

 Eleagnus argenteus, (Pursh.) With the preceding. 



EUPHORBIACEJ3. 



Euphorbia marginata, (Pursh.) Forks of the Platte. September 11. 



E. polygonifolia, (Linn.) South fork of the Platte. July 4. 



E. corollata, (Linn.) On thei&ansas. 



E- obtu?a!a, (Pursh.) LitlTe Bluef rijEj- of the Kansas. July 23. 



Pilinophytum capitatum, (Klotsch irt jFTegem. Arch., April, 1842.) Croton capitatum, (Michx.) 



Forks of the Platte. 

 Hmdecandra? (Esch.,) multiflora> n. sp. ; annual canescent, with stellate pubescence, dioecious j 



