POLYGONACE^. (BUCKWHEAT FAMILY.) 105 



2. A. umbellata, Lamb. (Pink Sand-Yerbena.) Annual; steins decumbent, leaves 

 oblong or ovate, attenuate at base into slender jjetioles; flowers pink. 



3. A. maritima, Xutt. (Red Sand-Verbena.) Stouter than the last; leaves broader 

 ■with shorter petioles; involucral bracts ovate; flowers bright red. From Santa Barbara 

 southward. 



4. A. fragrans, Nutt, of the Columbia River, has white flowers. 



Five other species belonging to this western genus are found east of the Sierra Nevada. 



Order 50. POLYGONACE^. 



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

 above 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. POLYGONUM, L. 



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

 usually 3- angled akene. Stamens 3 to 8. Styles or stigmas 2 or 3. Herbs with small 

 flowers oir jointed pedicels. 



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

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



2. RUMEX, L. 



Calyx of 6 sepals; the three outer herbaceous, spi-eading in fruit; the three inner 

 larger somewhat petaloid, covering the akene in fi-uit (then called valves), and often 

 bearing grainlike appendages on the outside. Stamens 6. Styles 3; stigmas tufted. 

 Introduced weeds with small greenish flowers crowded and whorled in panicled racemes. 



The Docks and Sheep-sorrel are examples of this genus. Of the dozen species on 

 this coast, half are introduced weeds. 



3. ERIOGONUM, Michx. 



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

 pedicels exserted, jointed to the flower, with bractlets at the base. Calyx corolla-like; 

 6-parted or deeply 6-cleft. Stamens 9. Akene triangular. — Herbaceous or somewiiat 

 woody plants, usually with a woolly or scurfy pubescence; the entire leaves without 

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

 Mississippi, of which 50 are Californian, mostly Alpine. 



Chorizavthe is a similar genus, in -whicli the involucres are 1-flowered and rigid. 



Orders AmaravtacecE and Clienojiodiacea are reprt sented by tiomely introduced ana native weeds. Many 

 of the latter order belong to the genus Chenopodium, viz.. Goosejoot, Lamb's-quarters, rigioeea, Jerusalem 



