SEEDLING STRUCTURE IN THE LEGUMINOSZ. 87 
Viciew with such a species as Medicago falcata, as Gérard (1881, p. 348) 
has done. This subject will be diseussed below (p. 107). 
So short is the hypocotyl in the hy pogeal Vicieæ that the terms descriptive 
of the level of transition here lose their significance almost completely; they 
are therefore not included in the table. 
Abrus precatorius in the form and structure of its seedling, as in many 
other features, shows a relationship with the Phaseolez rather than with the 
Viciez ; the root is tetrarch, the protoxylems all cotyledonary, and the 
transition low. 
The peculiar anatomy of the epicotyl in the Viciese (except Abrus and 
Cicer) is discussed below (p. 93) ; its derivation from the hypocotyledonary 
structure is described fully in Pisum sativum. 
PuasEOLEX. 
This tribe includes annual and perennial herbs, shrubs, and trees ; a large 
number of the species are climbing plants, a few are erect or prostrate herbs 
or sub-shrubs, while trees are infrequent (Erythrina, Butea). 
The seeds are often of considerable size ; the embryo is curved, except in 
Voandzeia subterranea, where it 1s straight. 
Germination is epigeal or hypogeal; within the limits of single genera 
both types can be found, e. g. Phaseolus and Erythrina. Even when epigeal 
the cotyledons are often very fleshy, scarcely green, are without stomata, and 
fall off early ; their wrinkled non-leaf-like appearance is very characteristic : 
they are usually, in such cases, attached by a comparatively narrow base to the 
hypocotyl. This type is found in epigeal species of Phaseolus and Erythrina. 
The cotyledons in the Glycinine are more foliaceous, though they also 
contain much food reserves. 
The seedlings are for the most part remarkable for their size, the hypocotyl 
being often very stout and, in the epigeal species, long. The smaller 
seedlings of Aennedya spp. have a curious distension of the cortical tissues 
in the lower half of the hypocotyl, which is thus shaped something like a 
champagne bottle. 
The prevailing type of symmetry is the tetrarch ; the root typically 
contains an almost square xylem star, solid to the centre, with slightly 
projecting protoxylems at the corners. There are, however, certain well- 
marked exceptions. In Canavalia spp. a pith is present in the root, which 
is still tetrarch. In a group of cases including the hypogeal Voandzeia 
subterranea and Erythrina arborescens, and the epigeal E. indica, a pith is 
present and a number of root-poles greater than four is developed ; heptarchy 
seems to be a frequent type of symmetry in these species, but, as is usual in 
such cases, some variation occurs in different specimens and at different 
levels. 
