30 MR. R. H. COMPTON: AN INVESTIGATION OF THE 
confirmation, and must be considered highly improbable in the light of the 
phenomena shown by L. mutabilis and L. hirsutus ; especially as Kattein’s 
figures of transverse sections show a structure very similar to that in these 
latter species, and as a figure by Naegeli (1858, pl. 5) shows the median polar 
protoxylem in the base of the cotyledon of L. luteus.  Naegeli also describes 
the course of the bundles in L. Lelumanni ; but his figures and description do 
not indicate the structure of the root, though the hypocotyl and cotyledons 
seem to have the same structure as that described for L. mutabilis. 
TRIFOLIELZE. 
ONONIS BIFLORA, Desi 
Hypocotyl tapering slowly to the root, Cotyledons ovate, covered with 
hairs. (Cf. Lespedeza; according to Lubbock, the only other instance of this 
outside the genus Ononis observed within the Leguminose.) Short one- 
sided cotyledon tube. 
The structure in many respects recalls that observed in ће Genistew. Тһе 
root is diarch, the xylem plates consisting of 1-2 rows of stout-walled and 
deeply-staining vessels; the phloem contains fibres. The xylem groups 
begin to broaden internally at the collet, and assume at first a Y-shape, and 
then at 10 mm. above the collet a T-shape. They break into triads about 
half-way up the hypocotyl; and the protoxylems, hitherto exterior in 
position, come to lie immediately between the collateral bundles formed from 
the metaxylems and the halves of the phloems. This arrangement of bundles 
constitutes the cotyledon trace ; the bundles, shortly after branching in the 
lamina, fuse in the melian plane and produce a definite midrib. 
The phloems are of a type not observed in the Genistec, but of general 
occurrence in the Trifoliee. Half-way up the hypocotyl each consists of а 
central group of clear cells flanked on either side by a group of densely 
protoplasmie companion-cells and sieve-tubes. 
Thus Ononis biflora exhibits certain characters of common occurrence in 
the Genistese, together with others found in the Trifoliez. 
ONONIS ROTUNDIFOLIA, Linn. (РІ. 5. figs. 76, 77.) 
Cotyledons ovate, leaf-like. 
The root may be triarch or tetrarch, the xylems consisting of 2—3-seriate 
plates of stout vessels and the phloem containing fibres (fig. 76). 
In a tetrarch seedling it was found that the root-like structure continued 
to about half-way up the hypocotyl without change. The intercotyledonary 
xylem then began to diminish in bulk, and three-quarters up the hypocotyl 
they had disappeared completely ; the four phloems, however, remainedin 
situ. Thus the structure became indistinguishable from that produced in many 
diarch seedlings (fig. 77, at 4 mm. below the cotyledonary node, where the 
