232 BOTANY. 



Polygonum imbricatum, Nutt. ("Watson, in Am. Naturalist, 7, p. 665). — 

 Low, 1 to 8 inches high, slender, often diffusely branched, smooth; spikes 

 short, dense ; bracts loosely imbricated, linear or oblong, 2 to 4 lines long, 

 with sometimes a narrow scarious margin, acute; sepals colored; stamens 

 3 or 5; styles one-third as long as the ovary; achenium glabrous. — South 

 Park, Colorado, July, 1873, Wolf (36). 



Polygonum amphibium, Linn. — Utah, 1871, 1872,. Watson's Report; 

 Colorado, 1873, Wolf (38). 



Polygonum amphibium, L., var. Muhlenbeegii, Meisn. in DC. Prod. 

 14, p. 116 — Camp Crittenden, Arizona, at 5,000 feet elevation, Septem- 

 ber, 1874, Rothrock (670). As in some of our Eastern specimens, the 

 peduncles are glandular-scabrous. 



Polygonum Peksicaeia, Linn. — Utah, 1871, 1872, Watson's Report. 

 Introduced. 



Polygonum nodosum, Pers. (Meisner in DC. Prod. 14, p. 118). — Stem 

 with the nodes much enlarged, 2 to 6 feet high; ochrese loose, becoming 

 glabrate, minutely ciliolate; leaves oblong or lanceolate, glandular-punctate 

 beneath, the lowest short-oval or ovate, the highest linear, the middle ones 

 6 to 8 inches long and 1 to 2 wide, tapering into a long acumination ; spikes 

 racemose, linear, attenuated upward, loose, nodding, on glabrous peduncles ; 

 bractlets ovate, acute, naked, longer than the pedicels; calyx flesh-colored 

 or white, without glandular dots, slightly nerved, including the 6 stamens 

 and 2-parted style; achenium lenticular, rarely triangular. — San Luis 

 Valley, Colorado, September, 1873, Wolf (40); Zuni Village, New 

 Mexico, at 6,500 feet elevation, July, 1874, Rothrock (160); Camp 

 Lowell, Southern Arizona, August, 1874, Rothrock (702). 



Polygonum Hydeopipeb, Linn. — Sanoita Valley, Arizona, at 4,500 feet 

 elevation, September, 1874, Rothrock (688). Introduced? 



Polygonum vivipaeum, Linn. — South Park, Colorado, July, 1873, 

 Wolf (43). 



Polygonum Bistoeta, Linn. — South Park, Colorado, July, 1873, Wolf 

 (44). Var. oblongifolium, Meisner, Willow Spring, Arizona, at 7,202 feet 

 elevation, July, 1874, Rothrock (228). 



