46 MR. R. H. COMPTON : AN INVESTIGATION OF THE 
each side, and just below the cotyledons eight or nine are present on each 
side of the stele. 
DESMODIUM CANADENSE, DC, 
The hypocotyl gradually tapers to the long primary root. The cotyledons 
are ovate, slightly secund, and a little thickened. 
The root is tetrarch, containing a solid xylem star ; a short distance below 
the collet the xylem breaks into four triangular groups arranged at equal 
distances round a small pith. Just above the external collet the xylems 
gradually spread into the tangential position ; the phloems divide at the 
same time ; and two-thirds of the way up the hypocotyl the stele contains 
eight tangential groups of metaxylem with a phloem group superposed upon 
each. The protoxylems behave in the usual manner ; the polar ones remain 
in the cotyledonary plane, being isolated from their metaxylems ; the lateral 
ones divide shortly after their metaxylems, and pass with them to join the 
polar metaxylems. 
Plumular bundles appear first in the intercotyledonary plane on both sides 
of the stele simultaneously (the first two leaves being opposite). A con- 
spicuous feature is the presence of tannin-sacs in connection with the 
plumular traces in the hypocotyl, and their complete absence in connection 
with the cotyledonary traces, cotyledons, and root. (Tannin-saes are abundant 
in the epicotyl, especially in the hypodermal layer and the pericyele.) 
The cotyledon trace consists of a median protoxylem and two compound 
metaxylems, vestiges of the lateral protoxylem remaining on the extre 
me 
edge ; the phloems have again fused, and two pass out to each cotyledon. 
DEsMODIUM GANGETICUM, DC, 
Decumbent or erect herb or undershrub. Cotyledons ovate. 
The transition phenomena are on the whole similar to those in D. canadense, 
but take place at a higher level. The small solid root-like xylem star 
continues half-way up the hypocotyl before being broken into four wedges 
by the appearance of a pith. At no period, also, are there eight collateral 
bundles in the hypocotyl, for the lateral half-xylems join the pol 
while the latter is breaking into a triad. 
throughout. 
ar groups 
Four phloems are present 
SCORPIURUS VERMICULATA, Linn. (Pl. 1. fig. 11.) 
The hypocotyl passes smoothly into the little-branched primary root. The 
cotyledons are linear and of great length, furrowed on the ventral surface, 
and with membranous connate wings at the base. ре Candolle (1825, pl. 12) 
gives a figure of the seedling. 
The root is tetrarch, a solid xylem star with four equidistant protoxylems 
being present. The phloems contain fibres. The transition is that usual for 
