SEEDLING STRUCTURE IN THE LEGUMINOSA. 27 
the cotyledons the metaxylems combine with the half-phloems to form four 
collateral stem-like bundles ; disorganised protoxylems remain at the poles ; 
and in this condition the cotyledons are entered. 
('ROTALARIA STRIATA, DC. 
Erect undershrub, reaching 120 em. Hypocotyl downy. Cotyledons 
oblong, with prominent midrib. Primary root replaced by a tuft of lateral 
rootlets arising from a slight swelling at the collet. 
The transition is, on the whole, like that in C. retusa with certain dif- 
ferences. Broadening of the xylems begins at the collet, and a transitory 
Y-shape is produced, followed by a T-shape, this almost immediately giving 
rise to a triad, whose median protoxylem lies well outside the line of the 
metaxylems. Half-way up the hypocotyl the bundles have become collateral, 
and so persist to the cotyledons, forming, together with the median polar 
protoxylem, the cotyledon trace. 
It may be remarked that cambial activity begins very early at the collet 
region, both here and in C. retusa: this no doubt being related with the 
early development of rootlets, as in many Phaseoleæ, &c. Another curious 
feature noted was the presence of a tannin-like substance in the vessels, 
a phenomenon also observed in Phaseolus radiatus. 
CROTALARIA INCANA, Linn. (P1. 5. figs. 73, 74.) 
Undershrub of 2-4 feet (Hooker, * Flora of British India?) ; erect herb, 
usually annual, attaining 2-3 feet (Bentham, * Flora of Australia’). Hypocotyl 
narrowing gradually to the root. Cotyledons oblong, twisted to one side, and 
with a conspicuous lateral sinus such as is caused by the hilum of the seed 
(Lubbock, 1892, p. 384), making them almost falcate. 
The transition closely resembles that of C. retusa, the early stages taking 
place in the collet region. Comparatively few xylem and phloem elements. 
are developed, however (fig. 73, in lower half of hypocotyl). The cotyledon 
trace consists of a pair of collateral bundles with a prominent median proto- 
xylem (fig. 74, at base of cotyledon), this structure being lost by anastomoses 
above the first pinnations of the veins. 
LABURNUM VULGARE, Presl. 
Fair-sized tree. The hypocotyl passes very gradually into the long tap- 
root. Cotyledons broadly ovate, strongly veined. Lubboek (1892, p. 407) 
and De Candolle (1825, pl. 5) give figures, the latter under the name 
Cytisus Laburnum. 
The root contains a pair of rather massive wedge-shaped xylems. The 
transition closely resembles that in Crotalaria striata, the initial Y and 
T stages being passed through rapidly at the base of the hypocotyl. Fibres. 
appear to be absent from phloem and pericycle. 
