RICINUS 



ROBIXIA 



1537 



filaments much branched, each with very man}' anthers; 

 rudiment of pistil none: the lower fls. longer pedicelled, 

 pistillate; sepals very deciduous; styles 3, plamoM: cap- 

 sule 3-loculed, .'{-seeded, explosively separating into _' 

 valved coccffi when ripe: seeds ovoid, with a large ca- 



2132. Ricinus communis. 



runcle, crustaceous testa and fleshy, oily albumen; coty- 

 ledons broad. ., 



A great many forms are known, many of which have 

 been distinguished as species by some, but most botan- 

 ists follow Muller (DeCandolle's Prodromus, vol. 15, 

 part 2:1061, 18(56), in referring them all to varieties of 

 the one species, R. communis, Linn., in which the fol- 

 lowing, listed as species in the American trade, may 

 doubtless be placed: R. Afric&nus, BorbonUnsis, Cam- 

 bodglnsis, cceriileus, Gibsoni, giganteus. macrocdrpus , 

 macrophylJus, Obermanni, Philippinlnsis , sangulneus, 

 spectdbiiis, tricolor, Zanzibar6nsis. See Vilmorin, Blu- 

 mengartnerei, p. 903 (1896). 



communis, Linn. CASTOR BEAN. CASTOR OIL PLANT. 

 PALMA CHRISTI. Figs. 2131-3. Half-hardy annual, 3-15 

 ft. high in the central United States, 30-40 

 ft. in the tropics. The large handsome leaves 

 (6 in.-2% ft.) and stems bright green to dark 

 red: capsules prickly or smooth. July to 

 frost. Probably originally from Africa or In- 

 dia, now scattered widely and naturalized in 

 all tropical lands. B.M. 2209. Cultivated in 

 most tropical and temperate countries from 

 the earliest times, for the oil of the seeds 

 (castor oil, Oleum Ricini) used in medicine 

 and in the arts, and in some places as a food- 

 dressing oil. The seeds contain a poisonous 

 principle. Also much used as a decorative 

 plant singly or in bed centers, giving a rich 

 tropical effect. Of rapid growth in any rich 

 soil. The seeds may be planted in May where 

 they are to grow, or sown singly in pots in 

 early spring and afterwards transplanted. 

 The species varies greatly in size and in the 

 form and size of the capsule, the form, size 

 and color of the seeds and color and glau- 

 cosity of the stem and leaves. The follow- 

 ing are some of the principal varieties : Var. 

 Cambodgensis, Hort. Lvs. dark colored; 



stems nearly black. Vitr. Gibsoni, Hort. Dwarf. :. ft., 

 Ivs. broasj purplish. Var. lividus, .lac,,, i /,-. tanguln- 



tUt. Hort. A'. <H,, muni ,,i. Hurt.) Slender; -ti-ni and 

 fruit blood-red, 8 ft. R.H. 7:1*2,1*:;. Var. Borboniensis, 

 Hort. Fifteen feet, Ivs. large, sinning, green or reddish. 

 Var. Zanzibarensis, Hort. A recent intn.du.-t.ion of large 

 size with enormous various colored Ivs. ami very largo 

 flat seeds. A.G. 16:383. I.H. 41:100. 



J. B. S. NOBTON. 



RIGIDELLA (Latin, somewhat rigid; referring to the 

 pedicels, which after the petals fall be.-oim- erect and 

 stiff). IridActcf. A genus of 3 species of Mexican half- 

 hardy bulbous plants allied to the well-known Tigridias 

 and distinguished by the inner perianth - segments; 

 these are inconspicuous in Rigidella, being very small, 

 ovate and erect, while in Tigridia they are larger, fiddle- 

 shaped and spreading. Lvs. broad, plicate, with chan- 

 neled petiole; fls. fugitive, bright red, pedicelled; peri- 

 anth-tube none; segments very unequal, outer oblong, 

 connivent in a cup in the lower third, then spreading or 

 reflexed; inner very small, erect, ovate, with a narrow 

 claw. Baker's Iridete, Baker, p. 70. 



immaculfcta, Herb. Stem 2-3 ft. long, forked: lower 

 Ivs. l%-2 in. long including petiole: fls. bright crim- 

 son, not marked with black. B.R. 27:68. F.S. 5:502; 

 21:2215 (fls. brick-red). F- w BARCLAY. 



RlVlNA (A. Q. Rivinus, professor of botany, etc., 

 at Liepzig, 1691-1725). Phytolaccdcece. A genus of 2 or 

 3 species of shrubs with herbaceous branches bearing 

 usually axillary racemes of small flowers, followed by 

 red berries the size of peas. Lvs. ovate, ovate-lanceo- 

 late or cordate-ovate : perianth-segments 4, small, equal; 

 stamens 4-8; style short; stigma capitate. The species 

 are natives of tropical America. The following makes 

 a good pot-plant for a warm greenhouse, and it is also 

 useful for growing as a summer annual in the open. 



humilis, Linn. ROUGE PLANT. Fig. 2134. Stem with 

 spreading branches, %-2 ft. high: Ivs. 1-3 in. long: 

 racemes slender, pendulous, many-fld., as long as the 

 Ivs.: fls. white, 1-1 % lines long: calyx pale rose: fr. 

 1-1% lines long; S. Florida. B.M. 1781. V. 5:75. 

 S.H. 2:111. Gn. 22, p. 68 (as R. Icevis). 



F. W. BARCLAY. 



ROAN or ROWAN. Sorbus Aucuparia. 



ROBtNIA (in honor of the two early French botanists 

 Robin). Leguminosce. Trees or shrubs, with odd-pin- 

 nate leaves and often spines for stipules: Ifts. stipel- 

 late: fls. in drooping axillary racemes : fr. a 2- valved 

 pod or legume, with several bean-like seeds. A genus 

 of plants of much merit for ornamental planting, and 

 in one case for its enduring timber. .All are of rapid 

 growth when young, reaching effective stages in a short 

 time. The facility with which they increase, both by 

 seed and by suckers, is sometimes a disadvantage. Va- 

 rieties are propagated by cuttings or by grafting The 



2133. Clump of Ricinus communis. 



