354 
DIPS AC US 
chiefly visited by bees. D . fullonum L. is the fuller’s teasel. The 
bracts are hooked ; the fruit-heads are largely used for raising the 
nap upon cloth. 
Dipteracanthus Nees = Ruellia Linn. 
Dipterocarpaceae. Dicotyledons (Archichl. Parietales). 16 gen. with 
313 sp., Seychelles to New Guinea, chiefly in India. They are mostly 
trees with entire leathery stipulate leaves, and racemose infls. of $ , 
regular, pentamerous firs. Receptacle flat or slightly concave. K 5 ; 
C, 5 convolute; A 5, 10, 15 or more; G (3), 3-loc., with 2 ovules in 
each loc. Fruit usually a 1 -seeded nut, enclosed in the calyx, some 
of whose leaves grow out into wings serving as an aid in wind-car- 
riage of the seeds. No endosperm. All contain resin-passages. 
Many are very valuable as timber trees, and in other ways. Chief 
genera : Dipterocarpus, Dryobalanops, Shorea, Vatica, Vateria. 
Placed in Guttiferales by Benth. -Hooker, in Cistiflorae by Warming. 
Dipterocarpus Gaertn. Dipterocarpaceae* 65 sp. India, Ceylon to 
Philipp. Is. The large amplexicaul stipules protect the young bud 
(cf. Magnolia, &c.). Several sp. yield wood-oil or Gurjun balsam, a 
resinous juice obtained by tapping the base of the trunk, and used as 
a varnish, &c. Many yield useful timber. 
Dipteryx Schreb. (Coumarouna Aubl.). Leguminosae (ill. 8). 8 sp. 
trop. Am. D . odorata Willd. furnishes the fragrant Tonka or Ton- 
quin beans (the seeds) used in snuff, perfumery &c. The fruit is one- 
seeded and indehiscent. 
Disa Berg. Orchidaceae (3). 60 sp. S. and trop. Afr. The median 
sepal is hood-shaped with a long spur at the back ; the labellum is 
usually small. “In order that insects may reach the copiously stored 
nectar, they must insert their proboscides on either side of the 
column ; and in accordance with this fact the viscid discs are turned 
outwards in an extraordinary manner. The pollinia are crooked, and 
when removed bend downwards by their own weight so that no move- 
ment is necessary” (Darwin). 
Dischidia R. Br. (incl. Conchophyllum Blume). Asclepiadaceae (11. 4). 
46 sp. Indo-mal., Polynes., Austr. Epiphytes (p. 173), climbing by 
adventitious roots, and with fleshy leaves which have a covering of 
wax. The most interesting sp. is the curious pitcher-plant, D. Rafflc- 
siana Wall., which besides the ordinary leaves, has “pitcher-leaves.” 
Each of these is a pitcher with incurved margin, about 10 cm. deep. 
Into the pitcher grows an adventitious root developed from the stem 
or petiole just beside it. The pitcher may hang with its mouth up- 
wards or may stand horizontally or upside down. No final explana- 
tion of its meaning has yet been made. It usually contains a lot of 
debris , apparently largely carried into it by nesting ants. Most of 
the pitchers contain more or less rain water, so that very likely they 
act as humus collectors and water reservoirs for the plant. The inner 
surface is coated with wax, so that the water cannot be absorbed by 
