38 



Perennial Crops 



Stout herb, iivitli large roots (becoming hollow) variously 

 branching from a rhizomatous croNvn : leaves mostly radical 

 (from the crown at or near the surface of the ground), blade 

 cordate-ovate, concave, the radical ones 12 to 20 in. long and 

 of similar width, margins entire but more or less long-sinuate 

 and usually somewhat undulate, with 3 strong upright and 2 

 basal ribs issuing from the top of the petiole, glabrous above, 

 lightly pubescent on the nerves beneath; petioles very stout, 

 shorter or longer than the blade, furrowed above and chan- 

 nelled on sides and back, the cross-section concavo-convex, 

 sheathed at the base, the sheaths eventually breaking away ; 

 stem Ivs. of similar description but successively smaller and 

 the long basal sheath conspicuous and encircling the stem like 

 a boot-leg: stem 4-6 ft. tall, hollow, strict but somewhat 

 branched, glabrous, shining, grooved, the nodes conspicuous : 

 flowers numerous in successive panicles, very small (about 

 2 mm. long), greenish white, on slender jointed pedicels exceed- 

 ing the length of the perianth, the latter with 6 obtuse lobes ; 

 stamens 9 (S-10), the large anthers equalling or exceeding 

 the lobes; pistil 1, with large 3-lobed stigma: fruits (" seeds" 

 of gardeners) cordate-ovate. ^4 to lo in. long, strongly 3-angled 

 and winged, brown, glabrous, weighing 14 to 26 mg., tightly 

 inclosing one large 3 -sided achene : longevity about 3 years. 

 — Siberia. The above description is drawn from the rhubarb 

 of cultivation, which is .commonly referred directly to R. 

 Rhaponticum. There is doubt as to the species, however, 

 and the vegetable-garden plant may be a hybrid or mutant 

 race (perhaps represented by R. hiihridiun, Murr.). or even 

 a different species. The species of Rheum are in need of fur- 

 ther study. The medicinal rhubarb is from roots imported 

 from Asia, probably from more than one species of Rheum ; 

 perhaps the roots of R. Rhaponticum are still used to some 

 extent for this purpose. The word "Rhaponticum" means the 

 Pontic rha or rhubarb ; Pontus was an ancient region in Asia 

 Minor. 



