﻿6 SCOTT, Early History of Seed-bearing Plants. 



the vegetative organs of Lyginodendron, while they are 

 unknown in any other carboniferous plant. The investiga- 

 tion, which we then carried out in collaboration, left no 

 doubt, from the evidence of structural identity and 

 intimate association, that in this seed we have the female 

 fructification of the plant Lyginodendron oldhaminm r 

 already so remarkable from the synthetic character of 

 its vegetative structure (Oliver and Scott, '03 and '04.) 



The discovery was in so far a surprising one, as it 

 showed that the plant had advanced further along the line 

 of spermophytic evolution than had been suspected from 

 its other characters. The seed is a highly organized one 

 (PL III., Fig. 2). Seated within a somewhat complex 

 cupule, it possesses a curious chambered testa with an 

 abundant vascular supply, and has a pollen-chamber, for 

 the reception of the microspores, of more elaborate 

 structure than that of any other known type of seed. 

 Broadly speaking, and without going into details, the seed 

 of Lyginodendron is on the level of that of a recent 

 Cycad. 



As is well known, a pollen-chamber, or excavation at 

 the apex of the nucellus of the ovule, for the reception of 

 the pollen-grains, is characteristic of the Cycads and the 

 Maidenhair-tree {Ginkgo biloba) among recent plants. It 

 was first discovered by Griffith in species of Cycas, at least 

 sixty years ago. The illustrations of this structure (Text- 

 figs. 1 and 2) are taken from Griffith's work published 

 in 1852, several years after his death (Griffith, '52 and '45.)*. 

 In Lagenostovia there is a central cone of tissue, pro- 

 jecting up the middle of the pollen-chamber, so that the 

 cavity of the latter forms a bell-shaped crevice, in which 

 the pollen-grains are sometimes found. (Text-fig. 3.) 



* I am indebted to Sir William Thiselton-Dyer for calling my attention 

 to Griffith's discovery, which has been too often overlooked. 



