POLYGONACE.E. (BUCKWHEAT FAMILY.) 105 



2. A. umbeData, Lajiil). (I'ink S;in<l-\'t'il»fna.) Annual; stems clecumlifiit. !< nvcs 

 l)I<)n^' or ovate, attenuate at base into sleu«ler jjetioles; flowers pink. 



3. A- tnantima, Xiitt. (Red Sand-Verbena.) Stouter than the hist; leaves lucader 

 •.vith sliortf'r petioles; involucral bracts ovate; flowers In-iglit red. From Sunta ]iari)ara 



i)Uthwanl. 



4. A. tragrans, Xutt, of the Columljia lliver, has white flowers. 



Fi\'e other species belonging to this m esterii genus are found east of the Sierra Xeva<l;u 



Order 50. POLYGONACE^. 



Herbs, with alternate entire leaves, and stipules in the form of sheaths, or obsolete, 

 ibove the swollen joints of the stem; the flowers mostly perfect, with a more or less per- 

 sistent calyx, a 1 -celled ovary, bearing 2 or 4 styles or stigmas, and a single seed- 

 Stamens 4-12 inserted on the base of the 3-6-cleft calyx. 



1. POIiYGCNUM, L. 



Calyx 5 parted; the divisions petal-like, persistent in fruit, and surroumiiug the 

 usually 3-anglcd akene. Stamens 3 to S. Styles or stigmas 2 or 3. Herbs witli s'.nall 

 flowers on jointed pedicels. 



Knot-weed or Yaid-grass and Smart-weed belong to this genus. About 20 species aia 

 found in California, of which 2 or 3 are probably introduced weeds. 



2. RUMEX, L. 



Calyx of 6 sepals; the three outer lierbaceous, spreading in fruit; the three inner 

 larger somewhat petaloitl, covering the akene in fruit (tlien called valves), and often 

 bearing grainlike appendages on the outside. Stamens (!. '"^tvles 3; stigmas tufted. 

 Introduced weeds with small greenish (lowers croM<letl and whorled in panicled racemes. 



Tiie J)ocks and Sheep-sorrel are examples of this genus. Of the dozen species on 

 tliis coast, half are introduced weeds. 



3. ZIRIOGONUM, Mirhx. 



Flowers borne in a many-to-few-flowered calyx-like involucre of united bracts; the 

 [)edicels exserted, jointed to the flower, with bractlets at the base. Calyx coroUa-Uke; 

 (i-jtarted or deeply G-clett. Stamens 9. Akene triangular. — Herbaceous or somewnat 

 woody plants, usually with a woolly or 9<;urfy pubescence; the entire leaves without 

 stipules and mostly radical; juice frequently acid. Over 80 species grow west of the 

 Mis8issi{)pi, ot which oO are Californian, mostly Al[>ine. 



ChnrUanthe. ig a similar genus, in '^liicli tbo involucreB are l-ttowerod ami rigid. 



Orders A maTantarciB and Cheiiopodiacea are repreeeuted by homely introduced ciia xiative weede Many 

 of the latter order belong to the genus Chenopodium, viz.. Goosejoot, Lambs-quarters, I'xgwtea, Jf-rusalem 



