306 



THE KINDS OF PLANTS 



spikes (in the Knotweeds in the leaf -axils) : calyx usually 5-parted: stamens 

 4-9: stigmas 2 or 3: black akene lenticular or triangular. 



a. Knotweeds: flowers sessile in the axils of tlie leaves, greenish and 



very small. 

 P. aviculare, Linn. Common knotweed. Doorweed. Fig. 193. Pros- 

 trate or creeping, bluish green wiry plant, growing along the hard edges of 

 walks and in yards, and commonly mistaken for sod: leaves small, mostly 

 oblong, entire: sepals very small, green with a broad white margin: sta- 

 mens 5 or more: stigmas usually 3. Annual. 



P. erectum, Linn. Taller knotweed. One ft. or more high : 

 $& leaves three or four times larger, oblong or oval and obtuse. 



Common annual. 



aa. Smartweeds ; flowers in terminal spikes, mostly pinkish. 

 b. Sheaths of leaves (surrounding stem) hairy on the 



edge, or the margin with a spreading border. 

 P. orientale, Linn. Prince's feather. Several feet tall, 

 soft-hairy: flowers in long cylindrical nodding spikes: leaves 

 ovate: stamens 7. India; cultivated. Annual. 



P. Persicaria, Linn. Smartweed. Lady's thumb (from the 

 dark blotch near the center of the leaf). Fig. 455. About 1 ft. : 

 leaves lanceolate: spikes oblong, dense and erect: stamens 

 usually 6: stigmas 2. Weed from Europe. 



P. Hydropiper, Linn. Smartweed. Herbage very pungent 

 or "smarty:" leaves oblong-lanceolate : spikes short and nod- 

 ding, the flowers greenish : stamens G: stigmas 3. Low 

 grounds. Annual. 



P. hydropiperoides, Michx. Smartweed. Herbage not 

 pungent: spikes slender and erect, the flowers whitish: sta- 

 mens 8: stigmas 3. In very wet places. Perennial. 

 P. acre, HBK. Smartweed. Herbage pungent : leaves linear or lanceo- 

 late, long-pointed: spikes slender and erect: flowers white or blush: sta- 

 mens 8: stigmas 3. Low grounds. Perennial. 



bb. Sheaths of leaves not hairy, nor the margin bordered. 

 P. Pennsylvanicum, Linn. Smartweed. Pungent: plant with conspicuous 

 glandular hairs above: leaves lanceolate: spikes short-oblong and erect, the 

 flowers purplish: stamens 8: stigmas 2. Low ground. Annual. 



455. 

 Polygonum 

 Persicaria. 



X. CARYOPHYLLACE^E. Pink Family. 



Herbs, with opposite, mostly narrow, entire leaves without conspic- 

 uous veins : flowers 4-5-merous, sometimes apetalous, with stamens 

 twice or less the number of sepals or petals, and 2 to 5 styles which 

 may be wholly separate or partially united: pod usually a 1-loculed 



