128 



HENDERSON'S HANDBOOK OF PLANTS 



DIM 



placed out of doors. It is essential, in order 

 to produce handsome plants, that the young 

 shoots be frequently stopped while the plants 

 are young, or they are liable to overgrow 

 themselves. Propagated by cuttings of the 

 firm side shoots in March or April. They are 

 natives of New Holland, and were first intro- 

 duced in 1794. 



Dimidiate. Divided into two unequal parts. 



Dimorpha'nthus. From dimorphus, two formed. 

 Nat. Ord. Araliac&B. 



This genus is composed of herbs and shrubs, 

 natives of China and Japan. Some of the 

 species are very ornamental plants for the 

 green-house or garden. D. Mandschuricus is a 

 deciduous shrub, said to be perfectly hardy. 

 Its handsome multifid leaves are nearly three 

 feet long, and of the same width, which gives 

 the plant a magnificent outline. The young 

 shoots of D. edulis are a delicate article of 

 food, mucli prized by the Chinese. They are 

 increased by seeds and from cuttings. 



Dimorpliism. A state in which two forms of 

 flower or leaf are produced by the same spe- 

 cies. 



Dimorphothe'ca. From dimorphus, two formed, 

 and theca, a receptacle ; disk florets of two 

 foi-ms. A genus of half-shrubby or herbaceous 

 plants, principally natives of South Africa. 

 They are all half-hardy plants, closely allied 

 to Calendula. Suitable for border culture in 

 summer, and for the cool green-house in 

 winter. The perennial species are readily 

 grown from cuttings. 



Dioecious. When a plant bears female flowers 

 on one individual, and male on another. 



Dio'n. (Sometimes spelled Dioon.) From dis, 

 two, and oon, an egg ; referring to the two- 

 lobed scales which compose the large cones 

 of the C3'cad, bearing a large nut-like seed at 

 the bottom of each scale ; otherwise from 

 seeds being borne in twos. Nat. Ord. Cycada- 

 cem. 



D. edule, the only species, is a beautiful 

 Palm-like plant. Its simple Zaniia-like stem 

 bears deep green pinnate leaves, whose leaflets 

 are sword-shaped and sharp pointed. The cone 

 consists of flat scales covered with wool, each 

 scale bearing two large seeds of the size of 

 Chestnuts, that yield a large quantity of 

 starch, which is used as arrow-root. D. edule 

 is extensively cultivated as an ornamental 

 green-house plant, and is pi'opagated by 

 suckers and seeds, and more commonly from 

 imported stems or trunks. It is a native of 

 Mexico, and was introduced in 1844. Syn. 

 Platyzamia. Miquel observes that this genus 

 is more closely allied to certain fossil Cycada- 

 cecB, than any other living representative of 

 the order. 



Dio'naea. Venus's Flj'-trap. Dione, one of the 

 names of Venus. Nat. Ord. Droseracem. 



D. muscipula, the only species, is indigenous 

 to the swamps of North Carolina and other 

 Southern States. Aside from all the fables 

 about this plant, it is one of extreme intei'est 

 to cultivators, owing to the irritability dis- 

 played by the stipulary fringes on the winged 

 leaves. The lamina of the leaf itself is divided 

 by the midrib into two nearly semicircular 

 halves, each of which is fringed with stiff 

 hairs. This leaf exactly resembles a minature 

 rat-trap. When the hairs are touched by a fly 



DIO 



or other insect, the sides of the leaf are 

 brought together with a sudden spring, im- 

 prisoning the intruder. Mr. Charles Darwin 

 and other writers claim that the DioncBa 

 not only catches and kills the insect, but 

 that its tissues absorb or feed upon them. 

 Our experiments, carefully and extensively 

 made during the summer of 1878, were such as 

 to cause strong doubts of the correctness of 

 this theory. The Dionaa is easily grown 

 in sphagnum moss, kept very moist when the 

 plants are in a growing state. They do rather 

 best when grown in a Wardian case or 

 under a bell glass and are always interesting 

 from their singular insect catching peculiarit3^ 

 Dioon. See Dion. 



Diosco'rea. Chinese Yam. After Pedacius 

 Dioscorides, a Greek physician. Nat. Ord. 

 Dioscoreacew. 



A genus of tuberous-rooted plants that are 

 extensively grown in Africa and the East and 

 West Indies for food. The roots grow to a great 

 size, are mealy, and considered to be easy of 

 digestion. They are roasted and eaten instead 

 of bread. The introduction of the Dioscorea 

 batatas into this country as an article of food 

 some years ago created quite a sensation ; 

 although we did not get a very valuable escu- 

 lent, we got a beautiful hardy climber, with 

 clean, glossy foliage and sweet-scented flowers, 

 that are produced in spikes at tlie base of the 

 leaves. This species was introduced from the 

 West Indies in 1733 and has been of late years 

 advertised and distributed under the name of 

 "Cinnamon Vine." D. villosa, Wild Yam, is 

 quite common in the thickets of New England 

 and to the south and west. 



Dioscorea'ceae. A natural order of twining 

 shrubs or herbs with tubers either above or 

 below ground, usually alternate leaves with 

 reticulated venation and small staminate and 

 pistillate flowers growing in spikes. They 

 are chiefly natives of tropical countries. Tamus, 

 however, is a native of Europe and of the 

 temperate parts of Asia. The plants are 

 mostly acrid, but contain also a large amount 

 of starch. Several species of Dioscorea pi'o- 

 duce edible tubers, which are known as Yams, 

 and are eaten like Potatoes. Tamus Com- 

 munis, black Bryony, has an acrid, purgative, 

 and emetic tuber, and a berried fruit of a red 

 color. Testudinaria elephantipes has a remark- 

 able tuberculated stem, and is called Ele- 

 phant's Foot or the Tortoise Plant of the Cape. 

 The central part of it is eaten by the Hot- 

 tentots. Thei-e are seven known genera and 

 160 species. Dioscorea, Tamus, and Testudinaria 

 are examples of the oi'der. 



Dio'stna. From dios, divine, and osme, odor ; 

 referring to the powerful perfume which 

 characterizes the species. Nat. Ord. Rutacem. 

 There is quite a large number of species, 

 all from the Cape of Good Hope. D. ericoides, 

 the species most generally cultivated, has 

 small white flowers, borne on slender heath- 

 like branches, with deep green leaves which 

 emit a strong penetrating smell when bruised. 

 It was introduced to cultivation in 1756, and 

 is valued for its bright glossy color, and neat 

 shrubby habit. 



Diospy'ros. Date Plum, Persimmon. From 

 dios, divine, and pyros, pear; literally ce- 

 lestial food. Nat. Ord. Ebenacem. 



