434 Robertson . — The ‘ Droppers' of Tulip a and Erythronium. 
The droppers of T. sylvestris may sometimes be used for ascent, instead 
of descent, for Oliver (1. c.) records that when the bulbs are planted at a 
depth considerably below their normal level the droppers may curve up- 
wards. 
(b) The Flowering Ttilip. 
The flowering Tulip differs from the immature plants described in the 
last section in that the foliage leaves are produced on the flowering axis 
instead of growing directly from the bulb. It is obvious from this that the 
main bulb cannot produce a dropper as there are no ground leaves of which 
it can be a continuation. However, the axillary lateral bulbs sometimes 
produce droppers which terminate upwards in rudimentary (or occasionally 
normal) foliage leaves (Fig. n). 
(c) The Seedling Tulip. 
By Miss Sargant’s kindness I have been able to examine the seedlings 
of an unnamed species of Ttilipa from Calcutta (Fig. 9 a). From the seed 
a long slender cotyledon emerges carrying at its tip the radicle and plumule. 
This tip dips down into the earth, and from it the main root and first 
adventitious root arise. But the shoot instead of emerging here as usual, 
remains inside the cotyledon tip, and by the continued elongation of the 
latter is carried down into the ground for some distance below the point of 
origin of the roots. The cotyledon thus forms a dropper to lower the first 
plumular bud well into the soil. I have followed the relation of the 
vascular system of cotyledon, dropper, and roots by means of serial sections. 
Miss Sargant 1 has already recorded that the transition from stem to root 
in this species is of the normal Tulipeae type, of which she figures Fritillaria 
imperialis as an example. 
In Fritillaria dropper formation does not occur, so perhaps it will be 
well (since the dropper is the organ with which we are especially concerned) 
shortly to describe and figure the transition phenomenain Tulipas^. (Calcutta). 
The cotyledon contains a pair of bundles which at the base approximate to 
form a double bundle with one protoxylem group (Fig. 9 b). The two 
phloem groups continue directly into the phloem groups of the diarch main 
root. The protoxylem group broadens into a flat plate at right angles to 
a line joining the centre of the two phloem groups, and the extremities of 
this plate form the protoxylem groups of the root. The dropper is supplied 
by a branch from each of the constituent bundles of the double bundle 
(Fig. 9 c). These two branches unite to form a V-shaped double bundle 
which presently gives off two laterals (Fig. 9 e). The first adventitious 
root arises opposite the dropper and a little below it (Fig. 9 d). 
1 E. Sargant, A Theory of the Origin of Monocotyledons founded on the structure of their 
Seedlings, Ann. of Bot., vol. xii, Jan. 1903, PI. Ill, and p. 23. 
