POLTGONACE^, (BUCKWHEAT FAMILY.) 105 



2. A. umbellata, Lamb. (Pink Sand-Verbena.) Annual; stems decumbent, leaves 

 oblong or ovate, attenuate at base into slender petioles; flowers jjink. 



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. POLYGONACEiE. "' 



Herbs, with alternate entire leaves, and stipules in the form 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 on jointed jjedicels. 



Knot-weed or Yaul-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. ^ -^ 



Cal3TC of 6 sepals; the three outer lierbaceous, spreading in fruit; the three inneif 

 larger somewhat petaloid, covering the akene in fniit (then called valves), and often 

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

 Introduced wee<ls with small greenish flowers crowded and whorled in panicled racemes. 



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

 this coast, half are introduced weeds. 



3. ERIOGONUM, Michx. 



Flowers borne in a many-to-few-flo\vercd 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 G-cleft. Stamens 9. Akene triangular. — Herbaceous or somewhat 

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

 stipules and mostly radical; juice frequently noid. Over 80 species grow Mest of the 

 Mississippi, of which 50 are Californian, mostly Alpine. 



Chorizanthe is a Bimllar gcuuB, In which tho involucres are l-flowcrcd ami rigid. 



Orders Amaranlacnr. and Vhenojiodxacea aro rrprcseiitt'd by honioly introduced ana native weeds. Many 

 of tho latter order belong to the genus Chtnopodium, viz.. Qooiffoot, Lamb't-quarters, I'iijweeii, Jerusalem 



