DISPERSAL 223 



with fleshy 1. covered by wax. The curious pitcher-plant, D. Raffle- 

 siana Wall., besides the ordinary 1., has pitcher-1. Each is a pitcher 

 with incurved margin, about 10 cm. deep. Into it grows an adv. r. 

 developed from the stem or petiole just beside it. The pitcher may 

 hang with its mouth upwards or may stand horizontally or upside 

 down. It usu. contains a lot of dtbris, largely carried into it by 

 nesting ants. Most contain rain water, so that perhaps they act 

 as humus collectors and water reservoirs. The inner surface is 

 waxy, so that the water cannot be absorbed by the pitcher itself, 

 but must be taken up by the roots. 



Developmental study shows the pitcher to be a 1. with its lower 

 side invaginated. The existing sp. illustrate all stages. Many, e.g. 

 D. bengalensis Colebr., have bi-convex 1.; others have the under 

 surface concave, e.g. D. (C.) Colly ris Wall., and the roots are de- 

 veloped under and sheltered by the concave 1. A further invagination 

 would lead to D. Rafflesiana. (Treub in Ann. Buitenz. III. 1883, 

 Haberlandt's Tropenreise, p. 168, and two papers in Ann. of Bot. 



1893-) 



DiscMdiopsis Schlechter (Dischidia p.p.)- Asclep. (n. 3). 2 N. G., 

 Phils. 



Dischisma Choisy. Scrophulariaceae (n. 7). 10 S. Afr. 



DiscMstocalyx (Distichocalyx) Lindau. Acanth. (iv. A). 7 trop. Afr. 



Disciflorae (RH.}. The 2nd series of Polypetalae. 



Disciphania Eichl. Menispermaceae. 8 trop. S. Am. 



Discocactus Pfeiff. (Echinocactits p.p. E.P.). Cact. (ill. i). 3 trop. 

 Am., W.I. 



Discocalyx Mez. Myrsinaceae (n). 8 Malaya, Polynesia. 



Discocarpus Klotzsch Euphorbiaceae (A. I. i). 3 Brazil, Guiana. 



Discoglypremna Prain. Euphorbiaceae (A. n. 2). i trop. Afr. 



Discogyne Sciilechter. Saxifragaceae (v). i New Guinea. 



Discolobium Benth. Leguminosae (in. 7). 6 Brazil, Paraguay. 



Discoluma Baill. (Chrysophylhtm p.p.). Sapot. (i). i Brazil. 



Discontinuous distribution, cf. Geographical Distribution. 



Discophora Miers (Kutnmeria Mart.). Icacin. 2 trop. S. Am. , 



Discopleura DC. Umbelliferae (in. 5). 2 N. Am. 



Discopodium Hochst. Solanaceae (2). i trop. Afr. 



Discostigma Hassk. = Garcinia L. p.p. (Guttif.). 



Discrete, separate. 



Disella Greene (Si da p.p.)- Malvaceae (2). 4 N. Am. 



Diselma Hook. f. (Fitzroya p.p.). Coniferae. i Tasmania. 



Disemma Labill. = Passiflora L. p.p. (Passifl.). 



Disepalum Hook. f. Anonaceae (i). 4 Indomal. 



Disparage Gaertn. Compositae (4). 5 S- Afr. 



Dispersis Sw. Orchidaceae (n. i). 30 trop. Afr., Madag., As. 



Disperma C. B. Clarke. Acanthaceae (iv. A). 7 trop. Afr. 



Dispersal of seeds may be occasional, as by floating trees, ice, &c., 

 tornados, mud on birds' feet, the voiding of the crops of carnivorous 

 birds, &c. (see Origin of Species, chap, xil), or regular, by ways 

 which may be classed in four heads. By wind are carried directly 

 the spores of ferns, &c., seeds of Pyrola, Orchidaceae, some Caryo- 

 phyllaceae, &c., by censer-mechanisms (see Aconitum), Campanula, 



