Botanical 
description. 
146 
. 
Botanical description. The tap root of lucerne descends to considerable depths (see page 149). 
The young plant consists of a number of aerial branches springing from a simple basal stock (rhizome) 
at the crown of the root. These branches ascend directly above ground and form a compact tuft. On 
the old plant, however, certain of the more robust stems elongale underground and become new branch- 
producing stocks. In this way, the simple stock or rhizome becomes two- (fig. B) or many-headed. 
The stems vary in height from one to three feet, are slightly angular, pubescent or glabrous, 
and branched. 
The leaves (fig. A) are compound and trifoliate. They are arranged in two ways: — Spirally on 
the main stem, two-rowed on its branches. The Jeaflets are pubescent and vary in form from oblong 
to obovate; the apex is emarginate, slightly toothed and mucronate. The stipules are acute. The i- 
florescence is an oblong, many-flowered raceme with blue or violet coloured flowers. The peduncles are 
axillary and longer than the leaf. The calyx is gamosepalous with five awl- shaped teeth, campanulate, 
pubescent on the ribs, but otherwise glabrous (fig. 1). The standard makes a sharp bend upwards and 
is slightly keeled in the middle line. The wings have a broad claw, from the point at which the 
claw joins the limb, beside, a fingerlike process extends backwards and inwards so as to grip the 
stamen-tube; immediately anterior to this is a deep invagination which fits into a corresponding fold of 
the keel; these folds also grip the stamen-tube. The feel (fig. 3) is rounded at the apex and has 
no beak. 
The stamen-tube (fig. 3) is composed of nine cohering filaments. When freed from the restraint 
imposed by the keel (in the manner described below), it bends with greal force, carries the stigma 
and anthers up with it and actually presses them against the standard, so great is the bending force. 
Miiller’s researches shew that this upward motion is due to the contraction of the upper filaments of 
the stamens, 
The pistil is composed of a hairy ovary containing several ovules, a slender style curved upwards 
and a terminal, bilobed stigma. 
The stamen-tube, as pointed out by Hermann Miiller, is imprisoned by the apendages and folds 
of the wings and keel; these articulate with one another and with the stamen-tube. The effects pro- 
duced by the visits of insects are as follows. The weight of the insect disarticulates the parts and 
sets the stamen-tube free. The upper filaments contract and the stamen-tube carrying the anthers and 
stigma with it is forcibly bent upward and pressed against the body of the insect. The sligma can 
now be impregnated by the pollen on the insect. At the same time, the body of the insect and probably 
the stigma as well are dusted with pollen from the flower. 
Hildebrand’s researches shew that the flowers of lucerne can form fruit when the visits of insects 
are entirely prevented. Up to the present time, no one has directly observed an insect in the act of 
freeing the stamen-tubes. Bees insert their probosces sideways into the flower and extract the honey 
withoul freeing the stamen-tube. Since butterflies are the only other visitors, Hermann Miiller con- 
cludes, that they do so. No internal changes going on in the flower can do this, for Hildebrand has 
often observed flowers quite withored in which the stamens had never been released. From these obser- 
vations, it is evident that the relations between the flowers and their insect guests are not yet 
understood. 
The fruit (figs. 5 and 6) is a spiral legume with two or three complete turns, many-seeded, 
from 4&4 to 5 mm. long and 3 to 4 mm, thick. The surface is net-veined and covered with adpressed 
hairs; on its periphery is a projecting rib (dorsal section) which, when the pod dehisces, detaches as 
a thread twisted on itself. | 
The seeds (figs. 7 and 8) are kidney-shaped (reniform), yellowish- brown, from 2 to 2*/2 mm. 
long and one mm. thick. The radicle is very distinct and the hilum occupies a depression on one of 
the narrow surfaces. 
