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, two and egg; each scale covers two ovules and the seeds are in pairs). Cycaddceae. Handsome foliage plants suitable for warm or temperate palm houses and for planting in the open far South.
This genus is said to be the closest to the fossil forms of any living representative of the family. It has the cones and twin seeds of Zamia and Encephalar-tos, with the flat woolly scales of Cycas, but without the marginal seeds and loose infloresence of the latter. - D. edule has a flat rigid frond which is more easily kept free from scale insects than Cycas revoluta, the commonest species of the family in cultivation A specimen at Kew had a trunk 3-4 ft. high and 8-10 in. thick, the crown spreading 8-10 ft. and containing 50 fronds, each 4-5 ft. long and 6-9 in. wide. Specimens of D. spinu-losum are reported with trunk 24 ft. high. Both sexes make cones frequently, the male cone being 9-12 in. long and the female 7-12 in. The seeds, which are about the size of Spanish chestnuts are eaten by the Mexicans. There are a few species in Mex. Prop, by seeds. Cult, same as Cycas.
Lindl. Leaves pilose when young, finally glabrous, 3-5 ft. long, pinnatifid, rigid, narrowly lanceolate segments, about 100 on each side, linear-lanceolate, sharp-pointed, widest at the base, rachis flat above, convex beneath: male cones cylindrical, female cones ovoid. Mex. B.M. 6184. G.C. III. 40:289. Gn. 55, p. 365. Gt. 48, p. 157. variety lanugindsum, Hort., is a very woolly kind. Gt. 48, pp. 154, 155. Variable.
Dyer. Plants 6-50 ft. high, crowned by a noble rosette of spreading leaves: leaves 4-6 ft. long, often with 100 lfts, on each side, these bearing 5-8 spines on each margin. This is one of the tallest of all the cycads, and is excelled only by the Australian Cycas media. It is very unlike D. edule, which has a stocky trunk and straight rigid leaves Mex. G.W. 4, p. 326; 5, p. 331. A.F. 7:461.
D. Dohenii, Hort. Discovered in mts. of Guatemala and named for Edward L. Doheney of Los Angeles. Pacific Garden, Nov. 1912: 13. - D. pectinatum, Hort. Like G. spinulosum: foliage described as "very handsome, owing to the very numerous pinnae and their close and regular arrangement. The texture is also firm and leathery, with a sharp spiny point to each pinna." Gn. W. 24: 5. - D. Pur-pusii, Rose. Trunk short, crowned with numerous stiff and ascending leaves 3 ft. or more long; pinnae 2-4 in. long, sharp-pointed, entire on the lower margin but usually with 1, 2, or 3 spine-like teeth on the upper margin: male cones 6-8 in. iong, the bracts with recurved ovate tips; female cones ovate, about 18 in. long, the bracts very woolly. S.Mex. Wllhelm Mlller.
L. H. B.†