32 MR. R. H. COMPTON : AN INVESTIGATION OF THE 
way up the hypocotyl. The stele becomes elliptical, a small pith appears, 
and the xylems on the major axis move apart somewhat; the xylems on the 
minor axis become somewhat crushed towards the centre, while spreading 
internally into a broad V-shape. 5 mm. below the cotyledons the polar 
xylems are divided in half and the metaxylem parts are rounding up into 
loose groups of spiral vessels mixed with parenchyma, which pass outwards 
on either side of the polar root protoxylems ; the lateral xylems lie in a 
tangential position and soon divide into halves, each half consisting of 
a metaxylem group and half the lateral root protoxylem. In this condition 
the half-lateral xylems move tangentially and fuse with the polar metaxylem 
bundles. 
The hypocotyl at this stage (2 mm. below the cotyledons) shows four main 
xylem bundles, each of which is derived from half of a polar metaxylem fused 
with the adjoining half of a lateral metaxylem to which the half of a lateral 
protoxylem is attaehed, the polar protoxylems retaining their position 
between the members of each pair of bundles. 
The phloems meanwhile remain in their original positions, so that on the 
fusion of the half-polar and half-lateral bundles they are almost radially 
outside the compound xylem. The arrangement of the phloem-tissues, 
however, changes somewhat—the large clear cells becoming external to 
a continuous band of sieve-tubes, companion-cells, and phloem parenchyma. 
When the cotyledonary tube becomes detached from the plumule, the 
vascular tissue is in the form of two pairs of almost collateral, but slightly 
oblique, bundles ; one pair supplying each cotyledon. The polar protoxylem 
lies between the pair, and the half-lateral protoxylems can be observed as 
small disorganised appendages to the outer edge of each xylem mass. 
The cotyledonary tube is very short, and is open on the side towards the 
flat edge of the cotyledon laminas at a lower point than on the other ; on this 
side the first leaf appears. 
TRIGONELLA FÆNUM-GRÆCUM, Linn. 
Hypocotyl tapers slowly to root. Cotyledons oblong-ovate, jointed to a 
petiole 2 mm. long, penninerved. De Candolle (1825, pl. 6) gives a figure. 
The root is tetrarch, and the whole structure agrees so closely with that of 
Medicago tribuloides that there is no need for further description. 
TRIGONELLA GLADIATA, Ster. (РІ. 5. fig. 78.) 
Hypocotyl tapering gradually to the root. Cotyledons on petioles 4:mm. 
long. (Dimensions in part from Lubbock (1892, p. 414) ; seedlings studied 
slightly etiolated.) 
The structure in seven out of the eight seedlings studied was quite similar 
to that described for Medicago tribuloides. In the eighth seedling, however, 
