Telangium [Calymmato theca) showing Structure . 169 
plicated in its free part which corresponds to the upper fifth of the seed. 
In this region it is usually composed of nine chambers radially disposed 
around the micropyle. The whole structure from within is like a fluted 
dome or canopy, the convexities of which correspond to the chambers. 
The vascular system of the seed enters as a single supply bundle at the 
chalazal papilla and branches a little below the base of the macrospore 
into nine radially-running bundles. Each of these bundles passes without 
further branching to the apex of the seed, running outside the macrospore 
and a little distance below the surface. At the canopy the bundles enter 
the chambers and end at the tips.’ 
A somewhat lengthy quotation has been made, as it is necessary to 
understand the structure of the seed if the comparison with the micro- 
sporangial sorus is to be appreciated. The transverse section 1 of the seed, 
if taken in the plane of the canopy, somewhat resembles a cartwheel, in 
which the nucellar apex forms the axle, the radial walls between the 
chambers the spokes, and the peripheral walls of the chambers the rim of 
the wheel. The comparison does not hold good, however, in well-preserved 
sections, as the chambers are seen each to contain large, thin-walled cells 
which support the delicate branch of the vascular bundle that is contributed 
to each. 
The correspondence which must have already suggested itself to the 
reader is between such a seed as Lagenostoma and such a synangium as 
Telangium Scotti. The chambers surrounding the nucellus seem to 
represent its sister sporangia, which have become sterile, the large- 
celled, thin-walled tissue and delicate vascular strand being all that repre- 
sents the ancestral sporogenous tissue ; while the micropyle corresponds 
with the original space between the tips of the sporangia. The seed in fact 
is assumed to be a synangium in which all but one of the sporangia are 
sterile, and form an integument to the one fertile sporange which has become 
a megasporange with one large megaspore. In Lagenostoma physoides 2 
the integumental ridges are continued into tapering tentacles around the 
micropyle, and this still further accentuates the resemblance to a sorus. 
In L. ovoides the number of chambers is often seven instead of nine. 
Hence we have only to imagine that one of the sporangia of a sorus of 
eight or ten sporangia gradually evolved megaspory, and that the remaining 
seven or nine sporangia became a sterile envelope, — a correlation in develop- 
ment which has many analogies in the animal and vegetable kingdoms. As 
soon as one of the sporangia became a megasporange the symmetrical 
arrangement of the sister sporangia would become an advantage and 
naturally follow. At the remote period of time at which the seed was 
1 Oliver, loc. cit., p. 461. 
a See Williamson, Phil. Trans., vol. clxvii, 1877, PI. XI, Fig. 77. A full account by Prof. Oliver 
of this seed will appear shortly. It should be compared with Telangium bifidu?n. 
