2952 



RHUBARB 



RHUS 



requires the lifting of the roots, it must be remembered 

 that they are worthless after having produced a crop. 

 Therefore, this method cannot be practised with as 

 great profit upon expensive land as can the method of 

 field forcing or when roots were used for forcing which 

 otherwise would be destroyed. Rhubarb-forcing in house 

 cellars should receive more attention, as it adds at slight 

 expense a pleasing vegetable to the winter dietary. 



Whatever the method practised, success will be at- 

 tained only when healthy well-developed roots, which 

 have been allowed to freeze, are used. Q. E. ADAMS. 



RHUS (ancient Greek name). Anacardiacese. 

 SUMAC. Ornamental woody plants, grown chiefly for 

 their handsome foliage, often assuming brilliant 

 autumnal colors, and some species also for their showy 

 fruiting panicles. See also Cotinus. 



Deciduous or evergreen shrubs, sometimes climbing 

 by aerial rootlets, or trees, with milky or resinous juice: 

 Ivs. alternate, without stipules, simple, 3-foliolate or 

 odd-pinnate: fls. dioecious or polygamous, small, in 

 axillary or terminal panicles; calyx 5-parted; petals 5, 

 imbricate; stamens 5, inserted below a broad disk; 

 ovary superior, with 3 styles: fr. a small 1-seeded dry 

 drupe, smooth or hairy. About 150 species in the 

 temperate and subtropical regions of both hemispheres. 

 Foliage and bark of most species are rich in tannin and 

 are used for tanning leather, particularly the Ivs. of 

 R. coriaria in S. Eu. From R. verniciflua lacquer is 

 obtained in China and Japan, used in the manufacture 

 of lacquer-ware; R. succedanea yields a vegetable wax, 

 used for candles in Japan, and also exported for various 

 purposes. R. Isevigata and some other S. African species 

 are valued for their timber. 



The sumacs are shrubs or trees with handsome simple 

 or usually compound foliage assuming in most decidu- 

 ous species brilliant autumnal colors, and with small 

 comparatively inconspicuous flowers in usually large 

 panicles, followed by small fruits which are deep red and 

 showy in many species. The only species with rather 

 showy flowers of creamy white color appearing in late 

 summer is R. javanica, while R. typhina, R. glabra, and 

 R. copallina are chiefly valued for their large pinnate 

 leaves coloring scarlet in autumn and also for the con- 

 spicuous panicles of deep red fruits remaining almost 

 unchanged on the plants during the winter; they are 

 well adapted for mass-planting on barren ground and 

 dry hillsides. Also R. verniciflua, R. succedanea, and R. 

 vernix have handsome large foliage, but are poisonous 

 like R. Toxicodendron, and for this reason are not 

 recommended for extensive planting. The deciduous 

 native species are hardy North, and R. verniciflua, R. 

 Potaninii, R. punjabensis var. sinica, R. javanica, R. tri- 

 chocarpa, and R. sylvestris are hardy as far north as Mass- 

 achusetts, while R. coriaria is tender, and the evergreen 

 species can be grown only in warmer temperate regions. 

 Most species grow well in dry and barren soil, only R. 

 vernix is a swamp-loving plant. Many species, particu- 

 larly R. Toxicodendron, R. glabra, R. typhina, and R. 

 copallina, spread by suckers and may become a nui- 

 sance in lawns and mixed plantations. Propagation is 

 by seeds sown in autumn or stratified; all species grow 

 readily from root-cuttings; some species, as R. canaden- 

 sis, may be increased by layers or cuttings of mature 

 wood. 



aromatica, 8. 

 canadensis, 8. 

 copallina, 18. 

 coriaria, 16. 

 dissecta, 20. 



glabra, 21. 

 hirta, 20 



laciniata, 20, 21. 



INDEX. 



tevigata, 5. 

 lanceolata, 18. 

 laurina, 3. 

 lucida, 6. 

 Michauxu, 19. 



SS&t 17. 

 ovata, 2. 

 Potaninii, 14. 



Satns's, 15. 

 quercifolia, 10. 



radicans, 10. 

 Roxburgh!!, 17. 

 semialata, 17. 

 sinica, 14, 15 

 succedanea, 13. 



SSSSf? 0111 10> 

 typhina, 20. 

 venenata, li 



^nfcfe \l 

 vernix, ii, 12. 



KEY TO THE SPECIES. 



A Foliage simple, evergreen. 

 B . Lvs. glabrous. 

 c. F r. pubescent, red. 

 D. Length of Ivs. 1-2 in., apex 

 , Dually obtuse. ..... 



^^^0^1 ^ . l\ Uurina 



BB Lvs j^ bescent \ ................ 4. mo iiis 



AA Foliage compound 

 ' B ^ s 



c. Plant evergreen. 



D. Petiole slender, terete ......... 5. laevigata 



DD. Petiole short, winged .......... 6. lucida 



cc. Plant deciduous. 



D - Fls - in e e catkin-like ra- 



B. jfc, long, 



with few rounded teeth ..... 7. trilobata 



EE . Ljts. pubescent, 1-3 in. long, 



crenate-serrate ............ 8. canadensis 



DD. Fls. in loose panicles: fr. gla- 



brous, whitish. 

 E - A P ex { </* obtuse ' margin 



Averts 'acute marainen- 



Hill*. ./I UV Jj <JJ UCoa UCUI-c/. fftfUf yvll l//fr~ 



tire or serrate . .. . .10. Toxicoden- 



BB> ,/&. 5 m more. [dron 



c. Infl. axillary: fr. glabrous, whi- 

 tish: Ifts. entire; Ivs. crowded at 

 the ena / the branches. 

 D - Uitdar side of Ifts. more or less 



of veins usually 10-12 

 E . Length of Ifts. usually 2-4 in., 



base cuneate ............. 11. vernix 



EE. Length of Ifts. usually 4-6 in., 



base usually rounded ...... 12. verniciflua 



DD> Under side of Ifts. glabrous, 

 grayish green, rarely green; 

 texture firm; with usually 15- 

 20 in ofveins ............ 13 . SUCC edanea 



cc Infl terminal: fr. harry, red. 

 D . Fruiting panicles pendulous: 

 Ifts. entire, or sometimes ser- 

 rate in young plants; rachis not 

 or slightly winged. 

 E. Number of Ifts. 5-7, rarely to 



^' ra f t^f^'^'V-, Y-' 14 ' P tamnu 

 EB ' **Hf *&d VTtiS 



ftUf f UtLlU USlflUtZU, t/fr If IK 



upper ^ 15 pun j a bensis 



DD . Fruiting panicle upright: Ifts. 



serrate except in No. 18. 

 E. Rachis winged. 



F - Lfts. obtusish, rarely over 2 



r ** ^ ong ...... ......... 16. conana 



FF. Lfts. acute, over 2 in. long. 

 Margin of Ifts. coarsely 

 serrate, base usually 

 rounded ........... 17. javanica 



GG. Margin of Ifts. entire or 

 remotely serrate, base 

 cuneate ............. 18. copallina 



EE - &**" terete or in No. 19 

 often wmged below the termi- 



7 , . r 



F ' L ^f b^ low 



shrub to 3 ft 19. Michauxii 



FF. Lvs. glabrous beneath or 

 pubescent on the veins, 

 glaucous. 

 G Branchlets and infl. 



densely hairy ........ 20. typhina 



GG. Branchlets glabrous, 

 glaucous: infl. finely 

 pubescent ............ 21. glabra 



1- jntegrifSlia, Brew. & Wats. Shrub or small tree, 

 occasionally to 30 ft. : Ivs. short-stalked, oval, obtuse or 

 sometimes acute, entire or spinosely toothed, glabrous, 

 1-2 in. long, very rarely 3-foliolate : . panicles hoary- 

 pubescent, 1-3 m. long; fls. white or pinkish: fr. ovate, 



