an archaic type of Seed from the Palaeozoic Rocks. 1 1 3 
Summary. 
The paper gives a full description of the Coal-Measure seed Physostoma 
elegans. It is a small straight seed about 6 millims. long by millims. 
across the widest part, and shows many points of agreement with Lageno- 
stoma. The integument, which is ribbed, is coalescent with the nucellus, 
except at the apex, where the ribs separate to form a whorl of ten tentacles 
surrounding the pollen-chamber. Ribs and tentacles alike are adorned with 
long tubular hairs reaching a length of nearly \ millim. ; these hairs give 
all sections of the seed a very characteristic appearance. It is thought 
probable that this multiple character of the integument is an archaic feature 
of which traces are discernible in Lagenostoma and allied seeds. The 
vascular system, which is very delicate, agrees generally with that of 
Lagenostoma . The nucellus is represented by a zone rich in secretory sacs, 
and a well-marked tapetum is also present. The megaspore is peculiar in 
possessing an apical papilla which protrudes into the floor of the pollen- 
chamber. It may be compared with the £ tent-pole ’ found in Ginkgo , and 
many Cordaitean seeds. The pollen-chamber is rich in pollen-grains which 
show traces of an internal cell- reticulum. Inside the pollen-grains, and 
associated with them, bodies have been detected which may be regarded as 
fossilized spermatozoids. 
A comparison of Physostoma with seeds of the Lagenostoma-^ roup 
shows numerous common features. Reasons are given for regarding 
Physostoma as the most primitive seed that has yet come to light. The 
plant that bore it has not been traced, but it may be referred provisionally 
to the Lyginodendreae. 
University College, London, 
October 1908. 
EXPLANATION OF PLATES V, VI, AND VII. 
Illustrating Professor F. W. Oliver’s paper on Physostoma elegans. 
\V. = Williamson Collection. S. = Scott Collection. U. C. L., R. and K. = University 
College, London, Collection. B. = Professor Bottomley’s Collection. M. H. =• Professor Bertrand’s 
Collection. 
PLATE V. Figs. 1-12 (Photographs). 
Figs. 1, 2, and 3. Series of three transverse sections of one seed, from preparations lent by 
Professor Bertrand, x 37. For explanation of references see under Fig. 4. 
Fig. 1, near the chalaza, shows the ribs of the integument in the lower half only ; the lacunae 
accompanying the vascular strands are distinct below, confluent above ; within follow the secretory 
zone and the tapetum ; the circular space in the centre is the embryo-sac. M. H. 369 (see p. 79). 
Fig. 2, across the middle of the seed, shows clearly the ribs of the integument, the vascular 
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