350 



THE KINDS OF PLANTS 



1. RHEUM. RHUBARB. 



Very large-leaved perennials, sending up stout hollow flower-stalks in 

 early summer which bear smaller leaves with sheathing bases : sepals 6, all 

 alike, withering rather than falling, and persisting beneath the 3-winged 

 achenes: stamens 9: styles 3. Old World. 



R. Rhaponticum, Linn. Rhubarb. Pie- 

 plant. Figs. 81, 82. Leaves 1 ft. or more 

 across, the thick petioles edible: fls. white, in 

 elevated panicles. 



2. RUMEX. DOCK. SORREL. 



Perennial often deep-rooted plants with herbage 

 bitter or sour: sepals 6, the 3 outer large and spread- 

 ing, the 3 inner (known as "valves") enlarging after 



512. Rumex Acetosella. nowerin g and one or more of them often bearing a 

 grain-like tubercle on the back; stamens 6, styles 3; 



flowers in panicles or interrupted spikes. 



a. Docks: herbage bitter: valves often grain-bearing: /lowers mostly perfect: 

 leaves not arrow-shaped. 



R. obtusifdlius. Linn. Bitter dock. Lower leaves oblong-cordate and 

 obtuse, not wavy: one valve usually grain-bearing. Weed from Europe. 



R. crispus, Linn. Curly dock. Leaves lanceolate, wavy or curled: all 

 valves usually grain-bearing. Weed from Europe. 



aa. Sorrels: herbage sour: valves not grain-bearing: 

 flowers dioecious: leaves arrow-shaped. 



R. Acetosella, Linn. Common or sheep sorrel. 

 Fig. 512. Low (1 ft. or less): Ivs. mostly arrow- 

 shaped at base: flowers brownish, small, in a ter- 

 minal panicle. Common in sterile fields. Europe. 



3. FAGOPtRUM. BUCKWHEAT. 



Fast-growing annuals, with somewhat triangular 

 leaves, and fragrant flowers in flattish, panicle-like 

 clusters: calyx of 5 parts: stamens 8: fruit a trian- 

 gular achene. Old World. 



F. esculentum, Moench. Common buckwheat. 

 Fig. 513. Leaves triangular-arrow-shaped, long- 



petioled: flowers white, in a compound cluster: achene with regular angles. 

 Flour is made from the grain. 



F. tataricum, Gaertn. India wheat. Slenderer, the leaves smaller and 

 more arrow-shaped and short-petioled : flowers greenish or yellowish, in 

 simple racemes: achene notched on the angles. Somewhat cultivated. 



513. 



Fagopyrum esculentum. 



