NATURE 



[Nov. 3, 1887 



with an oval cup-shaped body about 8 inches in .length 

 and 4 inches in breadth, with a sieve-net on the upper 

 truncated surface of the sponge body, extending evenly 

 over the oscular opening and over the layer of the 

 " spiculate cruciform spicules " in the net beams. We 

 may further add that there were to be found in the Museum 

 at Lisbon nearly a dozen specimens of Hyalonema which 

 were taken at Setubal. " Most of them were preserved 

 in spirits of wine ; they were certainly the very finest 

 collection of this remarkable Sponge in Europe. The 

 largest had a stem about 18 inches in height ; there were 

 no parasites of any kind on it, and it was furnished with 

 a sponge mass some 8 inches in diameter, and nearly as 

 much in height. A second specimen was very curious, 

 for here two apparently distinct individuals had become 

 matted together : the two glass ropes were interlaced, and 

 the two sponge masses had grown together" (Proc. 

 Dublin Nat. Hist. Soc, vol. v., 1869). It would have 

 been most important to have had the opinion of such an 

 authority as Prof. Schulze as to whether all these speci- 

 mens from Setubal are referable to Bocage's species ; and 

 whether, as we venture to think, Marshall's H. tho7nsoni 

 may not be only a well-marked variety thereof. It is 

 possible that by thus calling attention to the subject we 

 may yet learn more of the treasures of the Museum of 

 Lisbon, and nothing in these remarks can in the very 

 slightest degree detract from the merits and importance 

 of this splendid contribution to our knowledge of the 

 vitreous Sponges. E. P. W. 



THE FERN-ALLIES. 

 Hand-book of the Fern-Allies : A Synopsis of the Genera 

 and Species of the Natural Orders Equisetacece, Lyco- 

 podiacecB, Selaginellacece, Rhizocarpece. By J. G. Baker, 

 F.R.S., F.L.S., First-Assistant in the Herbarium of the 

 Royal Gardens, Kew. (London : George Bell and Sons, 

 York Street, Covent Garden, 1887.) 



AS the author states in the preface, " The present Hand- 

 book is planned upon the same lines as Hooker and 

 Baker's ' Synopsis Filicum,' and the two, taken in connec- 

 tion, cover the whole series of the Vascular Cryptogamia." 

 The total number of species describe d in the " Hand-book" 

 is 566, and as we may now place the number of known ferns 

 at about 3000, the fern-allies may be taken to represent 

 about one-seventh of the recent Vascular Cryptogams. The 

 fern-allies include only eleven genera, and about four-fifths 

 of the species belong to the two genera Selaginella (335 

 species) and Lycopodium (94 species). The eleven genera 

 are placed by Mr. Baker in four "natural orders,'' 

 while the Filices form a fifth : three of these, Filices, Equi- 

 setaceas, and Lycopodiaceae, being isosporous ; and two, 

 Selaginellaceae and Rhizocarpeae, being heterosporous. In 

 this way the relationship of the Rhizocarpeae to the ferns is 

 quite lost sight of ; the Selaginella s and Lycopods are separ- 

 ated more widely than is desirable, and no place is left for 

 the fossil heterosporous Equisetinae. The arrangement 

 adopted by Mr. Baker is very good for herbarium work ; 

 but for classificatory purposes it ignores certain palaeonto- 

 logical facts which we cannot at the present day afford to 

 overlook. Mr. Baker, however, does not deal with the fossil 

 types, and now that we have such a complete account of the 

 recent forms, let us hope that before long we may have as 



complete a synopsis of the fossil forms ; a work which 

 would be of the greatest interest and importance. 



In regard to the geographical distribution of the fern- 

 allies it is interesting to notice that Equisetum, Isoetes, 

 and Piliilaria predominate in the North Temperate Zone. 

 Lycopodium, Psilotum, Selaginella, Salvinia, and 

 Marsilea are eminently tropical ; and Phylloglosswn 

 is pecuhar to the South Temperate Zone. Like the ferns, 

 the fern-allies^ are best developed in the Tropics ; and in 

 the Tropics we also find the greatest number of peculiar 

 species. Thus, out of the 566 species, 484 are met with 

 in the Tropics of the Old and New World ; and no less 

 than 402, or 83 per cent., of these are peculiar to the 

 Tropics. As with the ferns so also with the fern-allies, 

 tropical America is richest in species, including 237 

 species, of which 212 are peculiar. The Southern 

 Temperate Zone yields only 83 species, of which 42, or 

 5 1 per cent., are peculiar, the fern-allies being thus much 

 less numerous than the ferns in the southern flora. In the 

 North Temperate Zone 150 species are met with, and of 

 these 48, or 32 per cent., are peculiar. The North 

 Temperate Zone is thus, like the South, deficient in fern- 

 allies as compared with ferns, and this is apparently due 

 to the small number of fern-allies as yet reported from 

 temperate Asia. Only 6 species occur in the Frigid Zone, 

 and, like the ferns, represent about i per cent, of the whole, 

 none of the species being peculiar. 



It is difficult to realize the amount of labour and research 

 that must have been spent upon the production of this 

 book ; but anyone who has attempted to study the genus 

 Selaginella will appreciate the masterly^ manner in which 

 Mr. Baker has dealt with the 335 species of the genus, 

 more than one-fourth of which he has himself described 

 for the first time. Most of the species of Selaginellaceae 

 and Rhizocarpeae have been described by Mr. Baker in 

 his papers on the subject which have appeared from time 

 to time, since 1883, in the fournal of Botany, but several 

 new species are described in " Fern- Allies " for the first 

 time, recent additions to the rich treasures of Kew. It is 

 to be regretted that Mr. Baker does not more particularly 

 refer to his papers in ihe Journal of Botany, and it is 

 hard to understand why, in the descriptions of Marsilea 

 conciftna and M. condensata, he has omitted the references 

 to th.Q Journal of Botany, 1ZZ6, pp. 179 and 281 respectively. 

 Then in transferring the matter from the Journal of 

 Botany he has altogether dropped out the habitat of Azolla 

 nilotica. There are also in the book not a few misprints, 

 and a want of care is shown in numbering and lettering 

 the sections of Selaginella. The index is also not quite up 

 to the mark, as in Marsilea, with numerous synonyms 

 omitted, and the misprints in Pilularia and Psilotum. 

 As the index of the " Synopsis Filicum " was published 

 separately as a catalogue of ferns, we may perhaps be 

 permitted to express a hope that this index will not be so 

 published until it is carefully revised. All that is wanting, 

 however, is only a little more careful editing, and the few 

 faults in no way detract from the sterling value of the 

 work. 



As the only modern synopsis of the group, it is a work 

 that must be in the hands of every botanist who deals with 

 the Vascular Cryptogams, and it will be a lasting monu- 

 ment to Mr. Baker's critical accuracy and great power of 

 dealing with a difficult set of plants. W. R. McNab. 



