RHAPIS 



RHEUM 



2927 



AA. Sts. becoming 8 ft. high. 



cochinchinensis, Mart. (Chamaerops cochinchinensis, 

 Lour.). Sts. often 6-8 ft.: If.-segms. much plaited, 

 oblong, obtuse; petioles short, straight and prickly. 

 Cochin-China. Intro, by Franceschi, 1900. 



N. TAYLOR.! 



RHAPONTICUM (old Greek name for rhubarb, the 

 same as occurs in Rheum Rhaponticum). Composite. 

 Under this generic name at least one species is still 

 catalogued, although the genus is now included as a 

 section of Centaurea. Nine species are recognized in 

 the group, extending from Morocco and Algiers to 

 China. They are more or less thistle-like stout herbs, 

 mostly or entirely perennial, with large solitary yellow, 

 pink or purplish heads, the Ivs. usually white-tomentose 

 beneath: florets all equal and perfect: fr. 4-angled; 

 pappus rough or feathery. Two species may be 

 described here, under the genus Centaurea. C. Rha- 

 ponticum, Linn. (Rhaponiicum scariosum, Lam.). Per- 

 ennial, 2-2 H ft-, with purplish fl.-heads: Ivs. tomen- 

 tose beneath, glabrous above, the lower ones ovate or 

 cordate and finely toothed, petiolate, the upper ones 

 sessile and oblong: outer scales of involucre scarious 

 (dry). Alps, Switzerland. B.M. 1752. Appears not to 

 be offered. C. cynarmdes, Link (R. cynaroides, Less.). 

 Perennial, from the Pyrenees region: heads few and 

 erect, purplish-fld. : Ivs. large, oblong to ovate, attenu- 

 ate at base, acuminate, the lower ones pinnately parted, 

 the upper scarcely pinnatifid, all the lobes acutely 

 toothed^ more or less tomentose beneath: scales of 

 involucre ciliate-serrate. Listed abroad for outdoor 

 planting. L. H. B. 



RHEEDIA (named after H. van Rheede 1635- 

 1691). Gutt'iferse. Trees, full of yellow sap, some of 

 them with edible fruit. 



Leaves rigid, leathery, lightly feather- veined: pedun- 

 cles axillary or lateral, the male fascicled, the female 

 fewer: fls. often small, polygamous-dioecious; sepals 2, 

 often connate at the base; petals 4, decussately imbri- 

 cated: ovary 3- (rarely 45-) celled: berry corticose and 

 indehiscent. About 30 species, Trop. Amer. 



brasiliensis, Planch. & Triana. Lvs. coriaceous, 

 ovate or oblong-ovate, obtuse and narrowed at the base 

 to a short petiole, apex obtuse or rather acute : fls. numer- 

 ous, in axillary clusters, polygamous: berry obovate, 

 short-beaked. Brazil and Paraguay. Intro, into Calif. 



edulis, Planch & Triana. Very smooth tree: Ivs. 

 lanceolate-oblong or oblong, acuminate, base acute or 

 attenuate: fls., the fertile ones, axillary, the pedicels 

 shorter than the fr.: drupe oblong, yellow. Cent. 

 Amer. Intro, into Calif. 



macrophylla, Planch. & Triana. Lvs. broad-lanceo- 

 late or lanceolate-oblong, acute at both ends, leathery: 

 fls. axillary, fascicled, 4-8; the pedicels twice the length 

 of the tis. : berry ovate. S. Amer. 



F. TRACY HUBBARD. 



RHEUM (Rha was the old Greek name for rhubarb). 

 Polygonactie. RHUBARB. Perennial (sometimes mono- 

 carpic) herbs grown for the large bold foliage and often 

 interesting inflorescence; and one for the edible leaf- 

 stalks. 



Leaves mostly radical, large for the size of the plant, 

 entire or divided, on stout thick petioles: sts. mostly 

 strict and rising above the heavy foliage, often tall, 

 making plants of striking habit: fls. perfect, small, 

 greenish or whitish, pedicellate, in numerous panicled 

 fascicles or racemes, the infl. elevated on stout mostly 

 hollow scape-like sts., which are provided with sheath- 

 ing stipules or ochreae (Fig. 3374) ; perianth 6-parted and 

 spreading; stamens 9 or 6; ovary 3-angled and bearing 

 3 styles, ripening into a winged or sometimes nearly suc- 

 culent achene. Species about 25, Syria and Siberia 

 to China, through the Himalayan region. 



Aside from the common rhubarb, Rheum Rhapon- 

 ticum, which is grown for the edible leaf-stalks, the 

 species are little known in general cultivation. Few 

 plants are more useful, however, for bold and striking 

 foliage effects; and these effects are heightened by the 

 towering flower-panicles. Most of the species are 

 hardy and easy to grow, but they 

 profit by a liberal winter mulch. 

 Rheums are usually seen to best 

 advantage against a heavy back- 

 ground of foliage or of rock (Fig. 

 1817, p. 1463). Even the common 

 rhubarb is a useful ornamental sub- 

 ject when well placed. In order to 

 secure large and fine foliage, the 

 soil should be rich and moist. The 

 species are propagated by dividing 

 the root-masses, preferably in 

 spring, leaving as much root as pos- 

 sible with each strong eye or bud. 



The dried rhizomes of rhubarb 

 are used medicinally. Several species 

 afford the officinal product. The 

 larger part of the dried rhubarb 

 _ imported from the Orient is prob- 



3374. Ochrea or stip- ably made from the crown or short 

 ular sheath of rhu- stem (not the flower-stem) of R. 

 barb. Rheum Rha- offidnale. R. Rhaponiicum is some- 

 ponticum. (XM) times grown for its medicinal roots. 



A. St. or scape with large imbricating k's. or bracts. 

 Alexandra;, Veitch. Tall, the fl.-sts. reaching 3-4 



ft., bearing great pale yellow overlapping leaf-like rather 

 obtuse bracts well above the dark glossy green and 

 relatively small elliptic-ovate crown-lvs. Thibet, W. 

 China. R.B. 35, p. 297. J.H. III. 61:297 A striking 

 plant of recent intro. 



AA. St. or scape without prominent imbricating foliage. 



B. Foliage undivided, the margins of the Ivs. nearly or 



quite entire. 



c. Lvs. (at least on the fl.-stalks) acute or acuminate. 



Rhaponticum, Linn. (i. e., Pontic Rha, "Rhubarb of 

 Pont us," a province of Asia Minor). RHUBARB. PIE- 

 PLANT (in the U. S.). WINE-PLANT. Fig. 3374. Strong 

 perennial, with thick clustered roots: petioles semi- 

 cylindric, plane above: If .-blades suborbicular, deeply 

 cordate at base, undulate, about 5-ribbed, glabrous and 

 shining above, pubescent on the veins beneath : panicles 

 tall and narrow, somewhat leafy, densely flowered, the 

 pedicels jointed below the middle, the fls. whitish: 

 achene oblong-oval. In deserts and subalpine parts of 

 S. Siberia. Nearly everywhere grown in this country 

 for the succulent acid petioles or leaf-stalks, which are 

 used in early spring for pies and sauces. Wine is some- 

 times made from the juice. In France, known usually 

 as an ornamental plant. There are several garden 

 varieties. See Rhubarb. 



undulitum, Linn. St. 4-5 ft., smooth: petioles semi- 

 terete, lightly channeled above, the If.-blades ovate- 

 cordate and strongly undulate (basal sinus not so deep 

 as in P. Rhaponticum), 5-7-ribbed, glabrous above and 

 puberulent beneath, the upper ones long: panicle nar- 

 row and leafy below, the pedicels jointed near the base: 

 achene ovate or oval. Siberia. Earlier and usually 

 smaller than R. Rhaponticum. 



cc. Lvs. obtuse or essentially so. 

 emddi, Wall. St. tall and leafy, 5-10 ft.: petioles 

 semi-terete, somewhat concave above, the margins 

 obtuse: If. -blades large, ovate, cordate, obtuse, some- 

 what undulate, 5-7-ribbed, the under surface and the 

 margin pubescent: panicles fastigiately branched, the 

 fls. dark purple, pedicels jointed below the middle: 

 achene large, ovate or oblong-oval. Himalaya, in alpine 

 and subalpine regions. Foliage has a coppery hue. 



