Rheum (Rha was the old Greek name for rhubarb). Polygonaceae. Rhubarb.
Perennial (sometimes mono- carpic) herbs grown for the large bold
foliage and often interesting inflorescence; and one for the edible
leafstalks.
Leaves mostly radical, large for the size of the plant, entire or
divided, on stout thick petioles: sts. mostlystrict 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 sheathing 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 succulent achene.—Species about 25, Syria and Siberia to China,
through the Himalayan region.
Aside from the common rhubarb, Rheum Rhaponticum, 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 background of foliage or of rock (Fig. 1817,
p. 1463). Even the common rhubarb is a useful ornamental subject 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 possible
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-ably made from the crown or short stem
(not the flower-stem) of R. Rhaponticum is some-times grown for its
medicinal roots.
R. acuminatum. Hook f. & Thom. Dwarf plant (seldom exceeding 3 ft.),
like a small form of R. emodi, withacuminate lvs., but fls.
considerably larger: said to be an attractive plant in cult, but to die
after flowering: sts. and infl. deep red-purple. B.M. 4877. G.
36:659.—R. gunneroides, Hort., is a garden hybrid, of German origin,
between R. emodi and R. palmatum. Himalayas.—R. nobile, Hook. f. &
Thom. St. simple, 3—4 ft., densely clothed with imbricated
downward-pointing bracts that conceal the short axillary peduncles:
lvs. ovate-oblong or rounded, entire. When the fruit is ripe, the
shingled bracts are torn away by the winds, leaving the long panicle
exposed, and this may stand while another panicle grows from the crown
and perhaps at some distance separated. Himalayas. R.H. 1876, p. 266.
I.H. 22:209. G.C. II. 13:793. G.Z. 20. p. 104. A remarkable plant.—K.
Ribes, Linn. 3-5 ft.: lvs. 1 ft. across, cordate to reniform. the
margins crisped or undulate, the blade puckered or blistered: fls.
green, drooping: frs. about 1 in. long, oolong-cordate, narrow-winged,
blood-red, showy. Asia Minor to Persia. B.M. 7591. "Rivas" or "Ribes"
is its Arabic name.—R. spiciforme, Royle. Dwarf: lvs. thick, orbic lar
or broadly ovate: fls. white, in a dense spike rising about 2 ft. W.
Himalaya.
L. H. B.
The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.
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