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398 



DIALYPETALiE. Plants with distinct 

 petals, in contradistinction to Gam.opetalce, 

 which have the petals united into a single 

 corolla. The term is a modern one pro- 

 posed to he substituted for Polypetalce, 

 which is more generally used in the same 

 sense, although it signifies literally plants 

 with many petals. 



DIALYPETALOTTS. The same as Poly- 

 petalous. 



DIALYPHYLLOUS. The same as Poly- 



sepalous. 



DIAMORPHA. The name of a small 

 crassulaceous North American herbaceous 

 plant, with whorled branches, alternate 

 cylindrical leaves, and small white flowers 

 with four-parted whorls. The ovary con- 

 sists of four carpels adherent at the base, 

 but divergent at the top ; the fruit is a 

 four-celled capsule. [M. T. M.] 



DIANELLA. A genus of Liliaceaz, con- 

 taining herbs from Australia and Tropical 

 Asia, distinguished by their fruit being 

 berry-like, their stem leafy, the flowers 

 perfect, the stamens inserted at the very 

 bottom of the six-parted perianth, and the 

 filaments incurved, thickened at the apex. 

 They have fibrous roots, grass-like leaves, 

 and paniculate blue flowers on drooping 

 pedicels. The berries are blue, many- 

 seeded. [J. T. SJ 



DIANTHUS. The Pink. An extensive 

 genus of Caryophyllacece, distinguished by 

 having two styles, and a cylindrical calyx 

 tube bracteated at the base. Most of the 

 species are natives of Europe, temperate 

 Asia, and the North of Africa. The leaves 

 are often rigid, glaucous and grass-like ; the 

 flowers crimson or pink in more or less 

 regular dichotomous cymes, sometimes re- 

 duced to fascicles or compact heads ; in 

 these latter the central flowers have no 

 bracts at the base of the calyx tube, but in 

 this case the lateral flowers, and in by far 

 the greater number of species, all the 

 flowers have two or more close-fitting 

 scales or bracts, often like a small outer 

 calyx. In Britain the following occur : 

 D. prolifer and D. Armeria, both annuals 

 with clustered flowers ; and D. plumarius, 

 or Pheasant's Eye ; D.Caryophyllus, or-Clove 

 Pink ; D. ccesius and D. deltoides, all which 

 are perennials with separate or solitary 

 flowers. D.Caryophyllus is the original of 

 the garden Carnations. D. barbatus, which 

 has fasciculate corymbose flowers and broad 

 leaves, is often seen in cultivation under 

 the name of Sweet William. [J. T. S.] 



DIAPENSIACE.E. (Diapensiads.) A na- 

 tural order of dicotyledonous plants, be- 

 longing to the subclass Corolliflorce and to 

 Lindley's gentianal alliance. Prostrate 

 undershrubs with crowded heath-like ex- 

 stipulate leaves, and solitary terminal flow- 

 ers. Calyx formed of five rather unequal 

 sepals, surrounded by bracts ; corolla 

 gamoperalous and regular; stamens five, 

 equal; filaments dilated and attached to 

 the corolla ; anthers two-celled, opening 

 transversely; ovary superior, three-celled; 



ovules seven or numerous ; style single. 

 Fruit a membranous or papery capsule, 

 surmounted by the persistent sepals, and 

 terminated by the rigid style ; seeds 

 pitted, peltate; embryo very small, in 

 fleshy albumen. The plants inhabit the 

 northern parts of Europe and North Ame- 

 rica. There are two genera, Diapensia and 

 Pyxidanthera, and but two or three spe- 

 cies. [J. H. B.] 



DIAPENSIA. Two beautiful little Al- 

 pine plants are the only representatives of 

 this genus, which gives the name to its 

 family. ' The best known is D. lapponica, 

 originally discovered in Lapland, but since 

 found in many parts of Northern Europe, 

 Asia, and America, where it has been 

 gathered as far south as the White Moun- 

 tains in New Hampshire : it is also found 

 in Japan. D. himalaica was found by Dr. 

 Hooker inSikkim growing on rocks and in 

 moist places in the sub-Alpine valleys at an 

 elevation of 8,000 to 10,000 feet. Both are 

 evergreen, and grow in dense tufts scarcely 

 rising more than an inch above the ground. 

 The stems are clad with closely imbricated 

 spathulate, and entire leaves, which in 

 D. lapponica are nearly half an inch long, 

 and in D. himalaica much smaller ; in the 

 former the stems are terminated by a 

 peduncle about an inch long bearing a soli- 

 tary white bell-shaped flower-about half an 

 inch across, surrounded by a five-leaved 

 calyx ; the border of the corolla has five 

 rounded flat lobes, and alternating with 

 these lobes are five stamens which have 

 their filaments dilated upwards. The 

 Himalayan species has much the habit of 

 the procumbent Azalea of the Scotch moun- 

 tains, and its purple flowers with short 

 stalks call to mind those of the opposite- 

 leaved saxifrage. The flower-stalks con- 

 tinue growing after the flower withers, 

 and when the capsule is ripe are frequently 

 more than two inches long. The only 

 other genus in the family (Pyxidanthera) 

 has got awned points to the anther-cells, 

 while in Diapensia the anthers are awn- 

 less. [A. A. B.] 



DIAPHANOUS. Transparent, or nearly 



DIAPHYSIS. A pra?ternatural extension 

 of the centre of the flower, or of an inflo- 

 rescence. 



DIARRHENA. A genus of grasses he- 

 longing to the tribe Festucem, distin- 

 guished by the panicles of inflorescence 

 being simple and contracted ; the spikelets 

 roundish, two to five-flowered ; glumes 

 two, unequal, acute, mucronate ; stamens 

 two or three ; styles two, feathery. Only 

 one species is described, D. americana, 

 which has creeping stoloniferous roots, 

 and erect simple stems, three to five feet 

 high. [D. M.] 



DIASCIA. A genus of Scrophulariacece, 



consisting of South African herbs, mostly 



annuals, very nearly allied to Nemesia and 



Heni'imeris. They differ from the former 



j in the corolla, which is flattened or con- 



