124 Seward and Gowan .— The Maidenhair 
of the integument and the endosperm 1 . Fig. 43 represents 
the endosperm of a fallen seed cut longitudinally ; in the 
centre there is the blunt papilla already described, on one 
side of which the egg-cell of an archegonium has remained 
undeveloped, a , while on the other an embryo, a\ has been 
produced. 
The thick fleshy portion of the Ginkgo seed is rich in 
secretory canals, but does not possess vascular bundles; the 
histological structure of the seed-coats has been described 
by Bertrand 2 . The embryo-sac is usually two-angled, and 
the archegonia, as described by Strasburger 3 , occur on a line 
joining the two keels of the woody part of the integument. 
Penzig 4 speaks of the occurrence of three-angled seeds, which 
he compares with seeds of Cycads 5 . It is of interest to 
notice the similarity between the structure of Ginkgo seeds 
and some of the Gymnospermous seeds described by Brong- 
niart 6 7 and others from Palaeozoic rocks. 
The morphology of the female flower has been variously 
interpreted by botanists; the opinions expressed on this 
question, as Celakovsky says, constitute ‘ ein lehrreiches 
Capitel wissenschaftlichen Suchens und Irrens V The peduncle 
of the flower arises in the axil of a leaf, and usually bears 
a single ovule (Fig. 6) on either side of the apex. Stras¬ 
burger in 1872 8 described the ring or collar at the base 
of each ovule as the rudiment of the first pair of leaves of 
a secondary shoot; in 1879 9 he spoke of the same structure 
as an arillus, and regarded the fleshy covering of the ovule as 
an integument, the peduncle with its two ovules constituting 
an inflorescence bearing two flowers. Strasburger described 
1 Cf. Bertrand (’78), p. 700 . 
2 Ibid., loc. cit. 
3 Strasburger (’72), p. 291 . 
4 Penzig (’94), p. 515 . Vide also Saporta (’84), p. 166 , and Saporta and 
Marion (’85), p. 58 . 
5 Braun (’75). 
6 Brongniart (’81) ; Hooker and Binney (’55), p. 153 . 
7 Celakovsky (’90), p. 2 . 
9 Ibid. (’79), pp. 74 and 120 . 
8 Strasburger (72). 
