318 



THE KINDS OF PLANTS 



2. RtTMEX. Dock. Sorrel. 



Perennial often deep-rooted plants with herbage bitter or sour: sepals 6, 

 the 3 outer large and spreading, the 3 inner (kn»wn as "valves") enlarging 

 after flowering and one or more of them often bearing a grain-like tubercle 

 on the back: stamens 6, styles 3: flowers in pan- 

 icles or interrupted spikes. 



a. Docks: herbage hitter : valves often grain- 

 hearing : floivers mostly perfect : leaves 

 not arroiv -shaped. 

 R, obtusifdlius, Linn. Bitter dock. Lower leaves 

 long-cordate and obtuse, not wavy: one valve 

 usually grain-bearing. Weed from Europe. 



R. crispus, Linn. Curly dock. Leaves lanceo- 

 late, wavy or curled: all valves usually grain-bear- 

 453. Rumex Acetosella. ing. Weed from Europe. 



aa. Sorrels: herbage sotir: valves not grain-bearing: flowers dioecious: 

 leaves arrow-shaped. 

 R. Acetos611a, Linn. Common or sheep sorrel. Fig. 453. Low (1 ft. 

 or less): leaves mostly arrow-shaped at base: flow- 

 ers brownish, small, in a terminal panicle. Common 

 in sterile fields. Europe. 



3. FAGOPtRUM. Buckwheat. 



Fast-growing annuals, with somewhat triangu- 

 lar leaves, and fragrant flowers in flattish, panicle- 

 like clusters: calyx of 5 parts: stamens 8: fruit a 

 triangular akene. Old World. 



F. escul^ntum, Moench. Common hucktvheat. 

 Fig. 454. Leaves triangular-arrow-shaped, long-peti- 

 oled: flowers white, in a compound cluster: akene 

 with regular angles. Flour is made from the grain. 



F. Tatdricum, Gaertn. India ivheat. Slen- 

 derer, the leaves smaller and more arrow-shaped 

 and short-petioled: flowers greenish or yellowish, in simple racemes: akene 

 notched on the angles. Somewhat cultivated. 



4. POL'tGONUM. Knotweed. Smartweed. 



Low weedy plants, or some exotic ones tall and cultivated, blooming in 

 summer and fall, the small pinkish or greenish flowers mostly in racemes or 

 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 the leaves, greenish and 

 very small. 

 P. avicul&re, Linn. Common knotweed. Dcorweed. Fig. 193. Pros- 

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



454. 

 Fagopyrum esculentum. 



