Dioon

(Greek, two and egg; each scale covers two ovules and the seeds are in pairs). Cycaddcew. Hand some foliage plants suitable for warm or temperate palm houses. This once powerful order is now nearly extinct, and the few remaining species are of the greatest scien tiflc interest and also decorative value. D. edulc has a
flat, rigid frond which is more easily kept free from scale insects than Cycas revoluta, the commonest species of the order in cultivation. A specimen at Kew had a
trunk 3-4 ft. high and 8-10 in. thick, the crown spread ing 8-10 ft. and containing 50 fronds, each 4-5 ft. long
and 6-9 in. wide. 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 chest nuts, are eaten by the Mexicans. Many Cycads yield arrowroot. This genus is said to be the closest to the fossil forms of any living representative of the order. The genus has the cones and twin seeds of Zamia and Encephalartus, with the flat, woolly scales of Cycas, but without the marginal seeds and loose inflorescence of
the latter. Prop. by seeds. Culture same as Cycas.