CALYCIFLOK.E. 275 



near Cucurbitaceae, the so-called parietal placentas of the latter being 

 rather an excessive form of the double axile placentas of such plants as 

 Diploclinium, and the placentas of Mezieria are described as parietal. Hil- 

 lebrandia has nearly regular flowers, and the ovary opens at the top as in 

 Reseda. It confirms the relationship to Datiscads. Beyoniella has a bell- 

 shaped gamophyllous perianth and definite stamens. They are natives 

 chiefly of India, South America, and the West Indies, and are much culti- 

 vated "for their beauty ; the oblique or unequal-sided leaves are character- 

 istic, whence they are sometimes called Elephant's Ears. Many Bego- 

 nias are remarkable for the production of adventitious buds in great 

 numbers from various parts of their surface. The roots appear to be bitter 

 and astringent, sometimes purgative. J3. malabarica, tuberosa, and some 

 others are used as pot-herbs. 



DATISCACE./E are diclinous apetalous herbs or trees, with alternate, 

 exstipulate, simple or compound leaves ; barren flowers with a 3-4-me- 

 rous perianth, and 3-7 stamens ; fertile ones with an adherent 3-4-toothed 

 perianth, a 1-celled ovary with 3-4 many-seeded parietal placentas, and 

 a dry fruit opening at the summit. They consist of a few species very 

 widely scattered. Datisca cannabina is found in the south-east part of 

 Europe, and has bitter and purgative properties. The Order appears PO 

 nearly related to Cucurbitaceae, Begoniaceae, and Loasaceae, that it is 

 undesirable to place it among the Monochlamydeae. D. cannabina is re- 

 markable as affording one of the examples of a tendency of the female 

 flowers of direcious plants to mature seeds without impregnation: this 

 phenomenon has been observed frequently in Cceloboyyne and MercuriaUs 

 among the Euphorbiaceae and in Cannabis ; but some error of observation 

 is to be suspected in these cases. Tetrameles is a large tree, the rest are 

 herbs. Genera : Datisca, L. ; Tetrameles^ K. Br. ; Tricerastes, Presl. 



HOMALTACE^E is a small Order of tropical trees or shrubs with inferior 

 ovaries and parietal placentas, related on the one hand to Passifloraceaa, 

 on the other to Loasaceae and Cactaceee. They are included in Samyda- 

 ceoe by Bentham and Hooker ; some of them have been introduced into 

 cultivation on account of their foliage ; the flowers are small. Genera 

 HumaHum, Jacq. ; Blackwellia, Commers., &c. 



LOASACEyE comprise herbs, sometimes hispid with stinging hairs ; 

 leaves opposite or alternate, without stipules ; calyx adherent, 4-5-parted ; 

 petals 5 or 10, in 2 circles, often cucullate; stamens numerous, free or in 

 bundles, adherent to the petals, often intermixed with staminodes or 

 abortive stamens ; ovary adherent, 1-celled, with several parietal placentas 

 or 1 central ; ovules pendulous ; seed with a loose testa ; embryo in the 

 axis of fleshy perisperm. Illustrative Genera : Mentzelia, L.; Bartonia. 

 Sims. ; Loasa, Adans. ; Blumenbachia, Schrad. ; Gronovia, L. 



Affinities, &c. A small Order. The genus Gronovia, with a climbing 

 habit, connects this Order with Oucurbitaceae, especially those with a 

 single seed; but in the latter Order the seeds are aperispermic. It is 

 likewise closely related to Cactaceae, differing importantly in habit only 

 from some genera. With Begoniads it agrees in the character of the seeds. 

 A further affinity exists to the epigvnous Order Onagraceae ; and among 



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