xxvi 
BOTANICAL TERMS AND DEFINITIONS. 
Disk, (Discus) applied to the central florets of a compound flower. 
The disk or central florets are generally yellow. 
DiPETALOUS, (Dipetala) corollas having two petals. 
DissECTUM Folium, vide Lbxf. 
DissEPiMENTUM, virfe Partition. 
Distichous, or Two-ranked, (Disticha) applied to leaves occu- 
pying two sides of the branch, but not regularly opposite 
at their insertion, as the fir, yew, &c. &c. ; applied to 
branches also when they spread in two horizontal direc- 
tions ; and to flowers placed in two opposite ranks. 
Diverging, {Divergens) applied to the position of leaves during 
sleep, and signifies that the leaflets approach at their base, 
and are open at their summits. 
DOLABRIFORME, vide HaTCHET-SH APED. 
Dotted, (Ptmctatum) applied to leaves being full of small, hol- 
low, transparent points, or having vesicles containing an 
essential oil. 
Down, {Lanugo) very soft, short hairs, scarcely discernible, cover- 
ing various parts of a plant. 
Drooping, (CerwMMs) pointing directly towards the ground; this 
term is applied to both peduncles and flowers. 
Drupe, (Drupa) a pulpy pericarp or seed-vessel, containing a sin- 
gle hard and bony nut, to which it is attached ; as the 
nectarine, plum, &c. The nut, though sometimes divided 
into separate cells and containing several seeds, does not 
part into distinct valves like the capsule. The drupe varies 
in consistence, being juicy in the peach, plum, &c. or 
firmer and fibrous, as in the cocoa-nut. 
Dust, {Pollen) of the anther. The pollen or dust is contained in 
the anther. In dry and warm weather the anther contracts 
and bursts, when the pollen is thrown out. From micro- 
scopic observation we find each particle of dust to be 
generally a membranous bag, either round or angular, 
smooth or rough, which on meeting with any moisture 
instantly bursts with great force and discharges a subtile 
vapour. 
Elliptical, or Oval, (Ellipticum) applied to leaves of an equal 
breadth, and rounded at each end, the longitudinal dia- 
vmeter being longer than the transverse one. 
Emarginate, or Notched, {Emarginatum) applied to leaves ter- 
minating in a small acute notch at the summit. 
Emerged, {Emersum) applied to the leaves of plants which are 
raised above water when the lower ones are under. 
