This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
(Greek, divine odor). Rutaceae. Small tender heath-like shrubs from southwestern Africa.
Leaves alternate or opposite, linear-acute, channeled, serrulate or sometimes ciliate, glandular-dotted: flowers white or reddish, terminal, subsoli-tary or corymbose, pedicellate; calyx 5-parted; hypogynous disk 5-sinuate, 5-plaited; petals 5; style short; stigma capitate: carpels 5. - Of the more than 200 species described, barely a dozen now remain in this genus, the others being mostly referred to allied genera, especially Adenandra, Agathosma and Barosma.
The plant known to gardeners (and described by Linnaeus) as D. capitata is now referred to Audouinia capitata, Brongn., which belongs in a different order (Bruniaceae) and even in a different subclass of the Dicotyledons (genus named for J. V. Audouin, born 1797, famous entomologist). It is a heath-like shrub 2-3 ft. high, with erect branches, and somewhat whorled, mostly clustered branchlets: leaves spirally arranged, stalkless, overlapping, linear, 3angled, roughish, with 2 grooves beneath: flowers crimson (according to Flora Capensis), crowded into oblong spike-like, terminal heads. Generic characters are: calyx adhering to the ovary, 5-cleft, segments large, overlapping; petals with a long, 2-keeled claw, and a spreading, roundish limb; stamens included; ovary half inferior, 3-celled, cells 2-ovuled; style 3-angled, with 3 small, papilla-like stigmas. - One species.
Fig. 1271. Native persimmon, Diospyros virgin-iana. (X 3/4)
In America, D. ericoides is more or less well known, and is put to various uses in floral decorations, in sprays, or branchlets cut to the required length, and stuck in formal designs as a setting for other flowers in the same manner and for the same purpose as Stevia is used, to give that necessary grace and artistic effect to the whole. This species, like most of the genus, has an agreeable aromatic fragrance in the foliage. It is a strong grower, loose and heath-like in habit and foliage, as the specific name indicates; flowers White and small, one or more on the points of tiny branchlets. While diosmas undoubtedly do best in soil suitable for heaths, that is, soil composed largely of fibrous peat, they are not nearly so exacting in their requirements in this respect, and can be grown in good fibrous loam and leaf-mold in equal parts, with considerable clean sharp sand added thereto. The plants should be cut back rather severely after flowering to keep them low and bushy; this refers more particularly to the above species, other members of the genus being of more compact growth and needing very little corrective cutting to keep them in shape.
D. capitata (properly Audouinia capitata) is a fine example of the latter class, and is much better than D. ericoides for exhibition and show purposes; flowers pinkish lilac, in corymbs. The propagation of diosmas by cuttings is similar to that of heaths, but much easier, The best material for cuttings is young wood. (Kenneth Finlayson.)
Linn. Much-branched, 1-2 ft., leafy: branches and twigs quite glabrous: leaves alternate, crowded, recurved-spreading, oblong, obtuse, keeled, pointless, glabrous: flowers terminal, 2-3 together, with very short pedicels; calyx-lobes ovate, obtuse; petals reddish, elliptic-oblong or obovate, obtuse, narrowed to a short claw, twice as long as the calyx; disk free and 5-lobed. B.M. 2332 under this name is in reality D. vulgaris variety longifolia. G. 33:501.
The plant cult, in Calif, as Diosma purpurea belongs to Agathosma (Greek, good odor), differing from Diosma chiefly in the presence of 5 staminodes and in the 3 or 4 carpels; it is A. villosa Willd., a shrub about 1 ft. high with upright branches, spirally arranged upright and imbricate leaves oblong-lanceolate, ciliate, pubescent beneath, 1/6-1/3in. long: flowers light purple, in dense terminal heads; pedicels unequal, at least the outer ones not exceeding the leaves S. Africa R.B. 5:369 (as Diosma hirta), H.I. 1:4. Another species sometimes cult, as D. purpurea is Agathosma Ventenatiana, Bartl. & Wendl. differing from the preceding species chiefly in the spreading leaves and in nearly equal pedicels exceeding the leaves L.B.C. 12:1122 (as Diosma hirta).
D. fragrans, Sims=Adenandra fragrans. - D. vulgaris, Schlecht., has narrower leaves than D. ericoides, and they are acute: branchlets minutely pubescent: leaves scattered, rarely opposite, linear, convex-carinate, subulate-acuminate: flowers corymbose, the petals white, or red on the outside: plant 1-2 or more ft. There are well-marked botanical varieties. Wllhelm Mlller.
L. H. B.†