SEEDLING STRUCTURE IN THE LEGUMINOS&JAE. 83 
slightly hairy. The cotyledons are frequently more or less deeply notched 
on one side owing to the pressure of the hilum and the accumbent radicle. 
A short cotyledonary tube is generally present. 
The vaseular symmetry varies within the tribe, diarchy, triarchy, and 
tetrarchy occurring. It is noticeable that these types appear to be associated 
with systematic position, The Astragalinee uniformly exhibit triarchy, at 
least in some individuals; the Indigofera spp. and the Psoraliinz display 
tetrarch and diarch roots. It appears probable that the proximate cause of this 
relation is the fact that in the Indigoferinz and Psoraliinz the first two leaves 
are usually opposite (alternate in Dalea annua, according to De Candolle), 
while in the Astragalinz they are alternate (see below, p. 103). 
The tetrarch structure in the majority of cases persists through the whole 
seedling. In Galega spp., however, it is reduced to diarch by the dis- 
appearance of the intercotyledonary protoxylems in the upper part of the 
hypocotyl. In many cases of triarchy each cotyledon receives one and a 
half root xylems ; but in several species a fourth protoxylem appears high in 
the hypocotyl; this fourth xylem may be shared equally between the two 
cotyledons, or (in one instance, Carmichaelia australis) may pass entirely to 
one cotyledon. In one seedling of C. australis the third protoxylem entered 
wholly into one cotyledon, the fourth into the other. The cases of diarchy 
in the root (Dalea and Amorpha) rest upon the assertion of Van Tieghem and 
Douliot, and no similar example was investigated. 
In Caragana arborescens the symmetry varies in different seedlings, being 
either triarch, tetrarch, or an intermediate condition. This may be connected 
with the variability in position of radicle and cotyledons, or with the varying 
diameter of the hypocotyl. 
Thus the variations of symmetry in the Galege show many parallels 
to those already described in the Trifoliee and Lotez, and to be mentioned 
in ће Hedysaree. 
The cotyledon traces contain a median polar protoxylem and a pair of 
metaxylems; lateral vascular bundles are not present, even in tetrarch 
seedlings, the phloem always remaining entire or only showing very faint 
signs of dividing. 
The level of the transition varies from high to intermediate-low. Though, 
on the whole, the highest transitions are found in the slenderest seedlings. 
yet in the case of the middle transitions there is no strict parallelism between 
size and level of transition ; this may be largely the result of imperfect 
classification of types, a task of considerable difficulty and uncertainty. 
HEDYSAREJE, 
The majority of species of Hedysareæ are herbaceous annuals or 
perennials; a few are shrubby, In many cases more than one stem is 
produced by the plumule. 
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