32 PllOCEEUINGS OF TUB 



and that of fii(jillaria itself, and of Lepidodendron (p. 436) is 

 interesting ; but the state of anatomical knowledge was not then 

 sufficiently advanced for the true homologies of the parts to be 

 recognised. Kegarding the affinities, Hooker says : " The points 

 by which SigiUaria (and Slir/mana) is allied to Lycopodiacese, 

 especially through the Lepidodendru, are probably quite sufficient " 

 (p. 437). Jle again rejects the idea of any affinity with Cycadeaj, 

 admitting only a certain analogy, a view in which he was un- 

 doubtedly justified. 



The most important of Hooker's palaeobotanical works is certainly 

 the third paper in the ilomoirs of the Geological Survey — " llemarks 

 on the Structure and Affinities of some Lepldostrohi,''' in which, for 

 the first time, he explained the true structure, hitherto quite 

 misunderstood, of the fructification of the Carboniferous Clubmosses. 



All his specimens of Lepidostrobus were found in nodules of 

 clay-ironstone, from the coal-fields of Staffordshire, Glamorgan, 

 &c. Curiously enough the best specimens occurred, as broken 

 frustules of cones, inside the stems of Lepidodendron elerjans and 

 other species, having been washed into the hollow stumps before 

 fossilization — the way in which this is likely to have occurred is 

 discussed in detail. He examined no less than 30 such trunks 

 from Staffordshire, all containing cones, which were sometimes 

 very numerous. 



Hooker begins his description by pointing out that three con- 

 ditions must be fulfilled in order to determine the relationships of 

 fossil cones. It is necessary to know : (1) the arrangement of the 

 individual organs and nature of the scales; (2) the anatomical 

 structure of the axis and other parts; (3) the nature of the 

 •contents — " there may be stamens or male organs, — ovaria or 

 female ones ; — or lastly, capsules containing reproductive spores 

 (which are peculiar to plants having no sexual system)" (p. 441). 

 At that time, immediately before the appearance of Hofmeister's 

 great Avorks, knowledge of the sexual reproduction of the Higher 

 Cryptogams was still very imperfect. In Lijcopodium, indeed, the 

 genus which Hooker probably had especially in mind, nothing 

 ■whatever was known of the sexual process till nearly 40 years later. 



The memoir is illustrated by eight plates, which give an admirable 

 idea of the external characters and internal structure of the cones. 

 The slightly restored figure of the scales and sporangia in radial 

 section (i)late 8. fig. 11) has become classical, and is remarkably 

 true to nature. The only defect is that the attachment of the 

 sporangium to its scale is shown too short, no doubt owing to 

 the section examined not having been so strictly radial as is 

 necessary to show the narrow attachment in its full length. 



He described the spores as " consisting of three or rarely four 

 sporules, -which are afterwards separated from one another " 

 (p. 451), but it is probable that what he really observed, in most 

 cases, was the split membrane of a single spore, and not the true 

 tetrads (except perha])s in the case shown in plate 0. fig. 11). 

 The mistake is extremely easy to make, as I kno-w from experience. 



