GERMINATION AND ROOT-SYSTEM 5 
soil that has been sterilized with boiling water, or in sawdust ; keep 
very moist and in a warm temperature, say 70°-80° F., and they 
will germinate in about a week. The first outgrowth is the coleo- 
rhiza or root-sheath, from which i slender radicle or primary 
root soon bursts, followed by two lateral roots ; as these burrow 
into the soil, they become clothed with absorbent root-hairs. 
Meanwhile, the plumule appears, completely sheathed by the im- 
perforate cotyledon which thus protects it during early growth. 
Here we have one of the characters of the Monocotyledons (plants 
having only one cotyledon or seedleaf), as distinguished from the 
other great class of 
flowering plants, the 
Dicotyledons, with two 
or more seedleaves. 
When the plumule 
has grown to. the 
height of an inch or 
two, the first foliage- 
leaf pierces the apex 
of the cotyledonary 
sheath, and emerges. 
Presuming that we 
have —_ experimented 
with the grains of 
Phalaris canariensis, 
its pink - coloured 
cotyledon will show in 
beautiful contrast to 
the first green leaf, 
The young plant is 
now able to provide 
its own nourishment , FF or ee reece section {irene fe lower 
though the store of a epelttenetis diane ee ape oe 
endosperm is not yet grain, and separating the embryo below from the endos- 
exhausted. If the perm above, and on the right; gv growing point of 
. plumule, and c its sheath (cotyledon) ; ~ radicle ; cf root- 
scutellum be examined cap; c¢Z root-sheath (coleorhiza) ; 44 rudimentary stem 
at this stage, with a (uypecoty}): usa wagenley, pune goraneane typecc! 
. with scutellum ; ce prismatic cells of scutellum ; 7% place 
high power of the where the radicle emerges, corresponding to micropile of 
microscope, we shall ovule. 
find that its innermost 
row of cells, which were at first prismatic in shape, now appear 
as slender strands, their elongation having taken place in order 
that they could remain in contact with the diminishing endosperm 
and absorb it from the remotest parts of the grain. The scutel- 
lum affords an absolute distinction between the Graminee or 
grasses, and all allied orders or families. Although it never grows 
out from the seed, it is in view of its function regarded by most 
botanists as a part, and the chief part, of the cotyledon. 
The primary root does not thicken into a taproot, and is soon 
indistinguishable fram the numerous slender lateral roots which 
