SEEDLING STRUCTURE IN THE LEGUMINOS.E. 61 
PHASEOLUS RADIATUS, Linn. 
An erect biennial. The hypocotyl slowly tapers downwards to the long 
primary root; in its upper part it is covered with long unicellular hairs, 
mixed with some club-shaped multicellular hydathodes. The cotyledons are 
fleshy, green, oblong. 
Tho transition resembles that of Abrus precatorius rather closely. It is 
essentially similar in nature to that found in other Phaseoline.  Intercalary 
bundles, however, are not present. Tannin-sacs are frequent, and many of 
the primary vessels while still young contain a tannin-like substance. 
PHASEOLUS HERNANDESII, Saw. (РІ. 8. fig. 109.) 
A tall climbing annual. The hypocotyl is long and stout. The cotyledons 
are thick and fleshy, not foliaceous, and are slightly green, but clearlyXfar 
more for storage than for assimilation. They fall off early and the epicotyl 
develops rapidly. The primary root is not long, but bears a great number 
of lateral rootlets just below the region of the external collet. The hypocotyl 
is sparsely covered with hooked unicellular hairs. 
The primary root is tetrarch, showing a solid four-pointed xylem core. 
Rapid dilation oceurs below the external collet, this being caused by the. 
appearance of a pith and its rapid inerease in diameter as we pass upwards. 
At the collet four widely separated groups of primary xylem are found, the 
metaxylem being arranged in the tangential position : these surround a 
bulky pith. Even at an early stage of growth a considerable quantity of 
secondary xylem and phloem is found in the region of the collet, so that the 
pith is completely surrounded with xylem, 
As we pass up the hypocotyl the amount of secondary tissue rapidly 
diminishes, and 2 em, above the collet very little is present. The positions 
of the xylem poles of the root are marked by four disorganised protoxylems. 
On either side of each of these, and separated from it by some little distance, 
is a tangential group of metaxylem ; there are therefore eight of these 
groups, which are in direct connection with the metaxylem at the collet. 
In between adjoining metaxylems are found intercalated xylem bundles, four 
in number, which connect on with the ring of secondary xylem at the collet 
region : these are the “ Zwischenstriinge " of Dodel (1872, p. 156). 
Half-way up the hypocotyl the protoxylems from the root have divided 
and each of the corresponding tangential metaxylems is now edged by a few 
crushed spiral vessels, The interealary bundles are now becoming much 
smaller. The xylem lies embedded in a perimedullary zone of dark-walled 
cells, The phloem is in four long bands, being interrupted in the planes of 
the xylem poles of the root: it consists, as in other Phaseolew, of small 
patches of sieve-tubes and companion-zells, many large tannin-sacs and 
phloem parenchyma. 
