298 W. Carrutkers — 77ie Forests of the Coal Period. 



horizontal pedicels. Three different forms of fruit belong to this 

 genus, or it should perhaps rather be called group of plants. 



The first of these is the cone named by Eobert Brown Triplo- 

 sporites,^ and described by him from an exquisitely preserved specimen 

 of an upper portion, in which the parts are exhibited as clearly in 

 the petrified condition as if they belonged to a fresh and living plant. 

 The large sporangia have a double wall, the outer composed of a 

 compact layer of oblong cells j)laced endwise, or with the long 

 diameter perpendicular to the surface ; the inner is a delicate cellular 

 membrane. The sjDorangium is filled with a great number of very 

 small spores, each composed of three roundish bodies or sporules. 

 Eecently Professor Brongniart has described a complete specimen of 

 this fruit,^ in which the minute triple spores are confined to the 

 sporangia of the upper and middle part of the cone, but the lower 

 portion, which was wanting in Mr. Brown's specimen, bears sporangia 

 filled with simple sjoherical spores ten or twelve times larger than 

 the others. 



The structure of another form of cone (Lepidostrohus) has been 

 expounded by Dr. Hooker.^ The arrangement of the different parts 

 comprising it is precisely similar to what occurs in Triplosporites ; 

 but the sporangia are filled with the minute triple spores throughout 

 the whole cone. 



The third form of cone, which I have described under the name 

 Flemingites,^ differs from the other two in having a large number of 

 small sporangia suj)ported on the surface of each scale ; and it agrees 

 with Lepidostrobus in the sporangia containing only small spores. 



In comparing these fossils with the living club-mosses, one is 

 struck with the singular agreement in the organization of plants so 

 far removed in time, and so different in size, as the recent humble 

 club-mosses and the palseozoic tree Lepidodendrons. 



The fruit of Triplosporites, like that of Selaginella, contains large 

 and small spores, the microspores being found in both genera on the 

 middle and upper scales of the cone, and the macrospores on those of 

 the lower portion. 



On the other hand, the fruits of Lepidostrobus and Flemingites 

 agree with those of Lycopodium in having only microspores. 



The size of the two kinds of spores also singularly agrees in the 

 two groups. This is of some importance, for among the recent 

 vascular crj^jDtogams there is a remarkable uniformity in the size of 

 the sjDores in the members of the different groups, even when there is 

 a great variety in the size of the plants. Thus the spore of our 

 humble Wall-rue is as large as that of the giant AlsopMla of tropical 



1 Some account of Triplosporite. By E. Brown. Trans. Linn. Soc. toI. xs. (1851), 

 p. 469, PI. 33 and 34. 



2 Notice sur nn fruit de Lycopodiacees fossiles. Par M. Brongniart. Comptes 

 Eendus, vol. Ixvii., Aug. 17, 1868. — Translated in Seemann's Journal of Botany, 

 vol. vii. (1869) p. 1. 



3 On the Structure and Affinities of some Lepidostrobi. By J. D. Hooker. 

 Memoirs of Geol. Surv., Tol. ii., Pt. 2 (1848), p. 440, PI. 3-10. 



* On an Undescribed Cone from the Carboniferous Beds. Geol. Mag., Vol. II . 

 (1866), p. 433. PI. 12. 



