DIO TA C A NTH US 2 1 9 



the digestive glands commence to secrete a ferment which acts upon 

 the proteids of the prey and renders them soluble, when they are 

 absorbed by the 1. (cf. Drosera). When the process is complete the 

 1. opens again. [Macfarlane in Contrib. from Bot. Lab. Pennsylv. 

 Univ. I. 1892.] 



Dioncophyllum Baill. Flacourtiaceae (5). i Congo. 



DionycMa Naud. Melastomaceae (i). 2 Madagascar. 



Dionysia Fenzl. Primulaceae (i). 15 alpine Persia, Afghanistan. 



Dioon Lindl. Cycadaceae. 3 Mexico. The seeds are ground into 

 meal, which contains much starch. 



Dioscorea Plum, ex L. Dioscoreaceae. 200 trop. and subtrop. D. 

 pyrenaica Bub. et Bordere (Pyrenees) is the only Eur. sp. They 

 have twining annual stems arising from tubers which in different 

 sp. are of different morphological nature. In D. Batatas Dene., &c. 

 the tuber arises by a lateral hypertrophy of the hypocotyl, and is 

 variously regarded as a rhiz. or a root; in D. sinuata Vel., &c. it 

 arises by lateral hypertrophy of the internodes above the cotyledon ; 

 in D. pentaphylla L., &c. it arises from the internode just above the 

 cotyledon together with the hypocotyl, whilst in D. villosa, L., D. 

 qitimpieloba Thunb., &c., there is a fleshy rhiz. The tubers are 

 known as yams; they contain much starch and are largely cult, for 

 food in trop., esp. Am. The best are perhaps D. alata L. (white 

 yam), D. cayennensis Link (negro yam), D. trifida L. f. (cush-cush ; 

 yampi). They are propagated by 'eyes' like potatoes. Small 

 axillary tubers often form on the main stem and may also be used. 



Dioscoreaceae (EP., BH.}. Monocots. (Liliiflorae; Epigynae BH.). 

 9 gen., 220 sp., trop. and warm temp., climbing herbs or shrubs with 

 tubers or rhizomes at the base (morphology varied; see gen.). L. 

 alt., net-veined, often arrow-shaped; infl. racemose; fls. reg,, usu. 

 dioec., inconspic. P (6), tubular at base; A 6, or 3 and 3 stds.; G (3) 

 usu. 3-loc. with axile, rarely i-loc. with parietal, plac. ; ov. usu. 2 

 in each loc., anatr. one above the other. Capsule or berry ; embryo 

 in horny endosp. The tubers of Dioscorea are valuable as food 

 stuffs; those of Testudinaria are also used. Chief genera: Dioscorea, 

 Testudinaria, Tamus. 



Dioscoreophyllum Engl. Menispermaceae. 5 trop. Afr. 



Dioscoreopsis O. Ktze. = Dioscoreophyllum Engl. (Menisp.). 



Diosma L. Rutaceae (i). n S. Afr. Heath-like xerophytes. 



Diosphaera Buser. Campanulaceae (i. r). 3 E. Medit. 



Diospyrinae (Warming). The 2nd cohort of Sympetalae. 



Diospyros L. Ebenaceae. 200 trop. Many sp. yield the valuable 

 wood ebony (y-v.). The sapwood is white and soft, the heart-wood 

 hard and black. D. reticnlata Willd. (Mauritius) and D. Ebemtm 

 Koen. (Ceylon) yield the finest ebony. D. quaesita Thw. (Ceylon) 

 yields calamantler wood. D. Embryopteris Pers. (gaub ; India) fr. 

 contains a sticky pulp, used for caulking. D. Kaki L. f. (Chinese 

 date plum, persimmon) fr. is used as a sweetmeat when dried, D. 

 Lotus L. (date-plum, temp. As.). D. virginiana L. (N. Am. ebony 

 or persimmon, U.S.) cult, for both wood and fr. (cf. Kew Bull. 1911, 



P- 234). 

 Diota.cantlrus Benth. Acanthaceae (iv. B). 2 Indomal. 



