7 1 
Trigonocarpus Shorensis , sp. nov. 
throughout of the hexamerous type, but also the absence of variation in the 
individual species. This stereotyped character suggests analogy with 
present-day Monocotyledons, and is in marked contrast to the variability 
exhibited by the Lagenostomales, not only as between different genera and 
species, but also as between individuals. For example, in Physostoma Y 
nearly 50 per cent, of the seeds had ten ribs, but the remainder exhibited 
from nine to twelve. In Conostoma the number was six or eight according 
to the species, with one recorded variant of Conostoma oblongum possessing 
seven. 2 In Lageno stoma Lomaxi the normal number was nine, 3 and for 
L. ovoides eight, with variation from six to nine. 4 Finally, in Gnetopsis 
elliptica the number of ribs was four, with perhaps two others vestigial. 5 In 
this series we see that there is almost every variation from four up to twelve, 
and whilst a multiple of three is by no means infrequent — a reminiscence 
perhaps of relationship to the Trigonocarpeae — the more normal feature is 
some multiple of two. 
Our knowledge of the structure of Conostoma and Gnetopsis has shown 
how narrow is the dividing line between radiospermy and platyspermy. 5 
Also the recent discoveries of Aneimites per tills 6 and Pecopteris Plukeneti , 7 
together with the obvious relationships between Pteridosperms and the 
Cordaiteae, render it necessary to consider the possibility of deriving bilateral 
forms from a trigonous group. The fact that the fructification Pecopteris 
Plukeneti was borne on a Medullosean type of foliage certainly indicates 
such a change, so that the analogy afforded by examples from the carpellary 
structures of the present-day Flora may not be without value. The Carices 
are represented in the British Flora by about fifty species, of which over 
thirty possess three stigmas associated with a triangular nutlet ; the re- 
maining species mostly have two stigmas, and the nut is either bilaterally 
symmetrical or plano-convex. In a few species with two stigmas the nut is 
slightly trigonous, and in Car ex paludosa, Good., the stigmas vary from three 
to two, accompanying which the nut is either trigonous or lenticular. 
As an example from the Dicotyledonous series, the Polygonaceae 
furnish us with a group in which triangular fruits are the rule. In part of 
the genus Polygonum , and in the genus Rumex , a triangular nut is associated 
with three stigmas. In the section Persicaria of the genus Polygonum , and 
in Oxyria , the fruit is lenticular and composed of only two carpels, as 
shown by the pair of stigmas. 
To come much nearer, the fructifications of Ginkgo biloba have been 
1 Oliver : Ann. Bot., 1909. 
2 Oliver and Salisbury : Ann. Bot., vol. xxv, 1911. 
3 Oliver and Scott : Phil. Trans. Roy. Soc., vol. v, 1903, p. 197. 
4 Prankerd, T. L. : Jour. Linn. Soc. Bot., vol. xl, No. 278, p. 463. 
5 Oliver and Salisbury, loc. cit. 
6 Dr. David White : The Seeds of Aneimites. Smithsonian Misc. Coll., vol. xlvii, pt. 3. 
7 M. Grand’ Eury, Comptes rendus, vol. cxl, p. 920, 
