HENDERSON'S HANDBOOK OF PLANTS. 



339 



DIM 



Dimidiato-cordate. When the larger half of 

 a dimidiate leaf is cordate. 



Dimorphous. Where similar parts of the 

 same plant assume different shapes or 

 characters. 



Dicecia, (adj. Dicecioux, Dioicus.) W T hen the 

 sexes of a plant are borne in different 

 flowers by distinct individuals; the dif- 

 ferent sexes on different plants. A sepa- 

 rate class, and also an order of another j 

 class, iu the artificial system of Linnaeus, ; 

 characterized by the unisexual flowers of j 

 the same species being produced on dis- 

 tinct individuals, as in Willows. 



Dioico-poli/gamotif. When some of the flow- 

 ers of a dioecious plant produce her- i 

 m aphrodite flowers. 



Dioscoreacece, (Yams.) A natural order of 

 monocotyledonous or endogenous plants, 

 belonging to the sub-class of Dictyogence. 

 They are twining shrubs or herbs with ! 

 tubers either above or below ground, 

 usually alternate leaves with reticulated \ 

 venation, and small staminate and pistil- j 

 late flowers growing in spikes. Perianth 

 six-cleft, in two rows, herbaceous and j 

 adherent; stamens six, inserted into the i 

 base of the perianth; ovary inferior, ; 

 three-celled; ovules, one or two, sus- 

 pended; style three-cleft. Fruit com- 

 pressed, three-celled, two cells of ten abor- | 

 tive; seeds albuminous; embryo in a | 

 cavity. They are chiefly natives of trop- | 

 ical countries. Tamus, however, is a na- 

 tive of Europe and of the temperate parts i 

 of Asia. The plants are mostly acrid, but 

 contain also a large amount of starch. 

 Several species of Diosoorett produce edi- j 

 ble tubers, which are known as Yams, 

 and are eaten like Potatoes. Tarn us com- I 

 munis, black Bryony, has an acrid, pur- 

 gative, and emetic tuber, and a berried 

 fruit of a red color. Text ud inarm /<'/i/mn- 



DIP 



lapsus has a remarkably tuberculated 

 stem, and is called Elephant's Foot or the 

 Tortoise Plant of the Cape. The central 

 part is eaten by the Hottentots. There 

 are seven known genera and one hundred 

 and sixty species. Dioscorea, Tamus, and 

 Testudinaria are examples of the order. 



Dipetalous. Consisting of two petals. 



Diphyllom. Two-leaved. 



Diploe. That part of the parenchyma of a 

 leaf which intervenes between the two 

 layers of epiderm. 



Diplostemonous. Having twice as many 

 stamens as petals. 



Diplotegia. An inferior capsule. 



Dipsacacece, (Teazleivorts.) A natural order 

 of gamopetalous Calycifloral Dicotyle- 

 dons or Exogens, belonging to Lindley's 

 Campanal Alliance. They consist of 

 herbs or undershrubs with opposite or 

 whorled exstipulate leaves, and flowers 

 in heads surrounded with an involucre. 

 Fruit dry, not opening, crowned by the 

 poppus-like calyx; seed albuminous. 

 They are mostly natives of the South of 

 Europe, Barbary, the Levant, and the 

 Cape of Good Hope. Some of the species 

 are astringent. Some are used in dress- 

 ing cloth. Dipsacus Futtonum is the 

 Fuller's Teasel, the dried heads of which, 

 with their hooked, spiny bracts, are used 

 in fulling cloth. The opposite leaves of 

 the wild Teasel, D. sylvestris, unite at 

 their bases so as to form a basin, in which 

 water collects; hence the plant was called 

 Dipsacus, or thirsty. There are six known 

 genera and about 170 species. Dipsacus, 

 AofawMO) Marina, and Gephalaria are ex 

 amples of the order. 



Dipteracece, (DipterocarpecK, Dipterads.) 

 A natural order of thalamifloral Dicotyle- 

 dons or Exogens, belonging to Lindley's 

 Guttiferal Alliance. They are large trees 



