76 University of Calif ornia Puhlications. [botany 



ultimate involucre is composed of small, narrow bracts united only 

 at the base, while in O. emarginafa they are united into a con- 

 spicuous, concave disk. 



Explanation of plate xiv. Oxijtheca emarginafa. —Fig. 1. Plant; 

 natural size. Fig. 2. Perianth, — spread out; enlarged eight diameters. 

 Fig. 3. Involucre, front folded down, exposing two open flowers and two 

 others with withering corollas; enlarged two diameters. Fig. 4. Pistil; 

 enlarged eight diameters. 



Oxytheca trilobata Gnii/. 



Not rare in dry soil of the upper part of the chaparral belt. 

 (Nos. 975, 2082.) 



Polygonum aviculare L. Yard Grass. 



An introduced weed in Strawberry Valley. 



Polygonum bistortoides Fursh. P. Bistorta L., of Bot. Calif. 



etc. 



Abundant in bogs and wet meadows of the Canadian Zone as 

 well as of the colder parts of the Transition. (Nos. 726. 2358.) 



Polygonum Douglasii Greene, Bull. Calif. Acad. 1. 125 (1885). 



P. tenue MiCHX., of Bot. Calif. 



Of the same range as the last but in comparatively diy soil 

 and not so common. (No. 2446.) 



Polygonum Watsoni Small, Monogr. N. A. Polyg. 138 (1895). 



P. imhricatum Nutt., of Bot. Calif. 



Collected along a stream in Tahquitz Valley at 8000 ft. alt. 

 (No. 2354.) 



Pterostegia drymarioides F. d- M. 



Chalk Hill, among rocks. (No. 2080.) 



Rumex salicifolius Wei)im. Willow-leaved Dock. 



In the Transition Zone, reaching 9000 ft. alt. (Nos. 2474, 

 2525.) 



CHENOPODIACE.E. 



Chenopodium album L. Pigweed. White Goosefoot. 



Collected at various places below 9000 ft. alt. (Nos. 2178, 

 2473.) 



