42 DEVELOPMENT OF THE FLOWER 
The structure of the anther is essentially the same, but 
the grains contain more granular matter which, with the oi 
spots, forms a conformable nucleus. 
The óvula are now helmet-shaped, the groove is of large 
size; they are quite cellular and solid, although the turgidity 
of the superficial cells towards their geometrical apices to the 
_ centre, leads me to suspect that the cavity of the embryonary 
sac is about to develipi the part "elus would correspond to 
the apex of th . How invariably 
new tissue that is to be, is s of this colour by tyanannited light. 
The leaf consists of a cutis, on either side is a central stra- 
tum of vessels, and on either side of this a green parenchyma; 
. of this the upper (or posterior) is much the most dense ; 
it is at right angles with the vascular strata, and from a pecu- 
liar arrangement of the green matter, appears to be travers- 
ed by close parallel horizontal lines of dark green: the under 
stratum is somewhat cavernous, almost twice as thick as the 
upper, and is likewise at right angles with the vascular stra- 
tum, at least near the cutis; near the vessels it is more irre- 
gular and cavernous. I do not believe these are strata of 
vessels; it appears decidedly one envelope, as always seems 
to be the case in fibrous tissue. | 
With the green matter which is amorphous under 1-20th, 
there occur large grains of greenish tints, often solitary, 
generally so perhaps in the upper stratum; they have the 
peculiar rotatory motion. 
Although the inner margin of the pollen mass, undoubted- 
ly appears thickest, yet this is more apparent than real, and 
perhaps is owing to the two side margins being more ap- 
proximate here than elsewhere ; when spread open it is 
found to have an uniform structure. 
Those pollen grains are first acted upon by reagents that 
are near the place whence the boyaux issue; acids and io- 
dine cause an appreciable action by rendering opaque the 
granular contents of the pollen grains, which in the ordi- 
nary state appears to be quite transparent! the mass having 
the appearance of a yellow flat piece of wax with cellu- 
lar sub-divisions. 

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