10 MR. R. H. COMPTON : AN INVESTIGATION OF THE 
The cotyledons are erect, large and fleshy, ovate with a cordate base. 
Lubbock figures the upper part of the seedling (1892, p. 469). 
The root is tetrarch, containing four wedge-shaped groups of xylem 
surrounding a pith which is present throughout (fig. 34). 5 mm. below the 
external collet the metaxylem forms a continuous ring, 3—4 cells thick, round 
a fair-sized pith; the four protoxylems project outwards from this ring 
(fig. 35). The pith dilates as we ascend to the collet, and the ring of xylem 
becomes more extended. The phloem remains in four long ares, and no fibres 
are developed. In the lowest 5 mm. of the hypocotyl the amount of xylem is 
considerably reduced, and the ring breaks up into four triads, each comprising 
a median protoxylem and. a pair of metaxylem wings (fig. 36); the triads 
lateral to the now elliptical stele are somewhat longer tangentially than the 
terminal ones. The reduction in bulk of the xylem continues throughout 
the hypocotyl. The lateral protoxylems split and join their metaxylems just 
below the node. Each cotyledon receives five bundles of xylem, viz. a polar 
protoxylem, a pair of polar metaxylems, and a pair of lateral metaxylems 
witn their protoxylems attached. Тһе phloem, however, remains in two long 
tangential bands, the gap between them being over the polar protoxylem 
(fig. 37). 
CAESALPINIOIDE.E. 
AMHERSTIE,E, 
TAMARINDUS INDICA, Linn. 
A large tree. The hypocotyl is uniformly thick except just below the 
cotyledons, where it narrows somewhat. The cotyledons are squarish-oblong, 
rather thick and fleshy, erect and clasping the young plumule, later caducous, 
stout. The axis narrows gradually below the external collet to the long and 
rather stout primary root. A curious feature is the early development of 
cork in the hypocotyl; the phellogen is situated deep in the cortex ; by the 
time the cotyledons have fallen eff the hypocotyl is brown, contrasting sharply 
with the green stem above the cotyledonary node. De Candolle (1825, p. 24) 
gives a figure of the seedling. 
The root contains a large pith throughout. The xylem forms a continuous 
band surrounding the pith : this mainly consists of metaxylem, but secondary 
xylem develops very early; the protoxylems are four in number, but are 
rather feeble, and project slightly on the exterior of the metaxylem ring. 
The phloem is in four long bands alternating with the protoxylems. А phel- 
logen commences activity very early, and the cortex is quickly thrown off. 
At the external collet the pith is of great size: the primary xylem is in 
four triads, each being composed of a small median protoxylem and a pair of 
metaxylems. The four triads are all similar: they are united by a continuous 
