68 



NA TURE 



[November 17, 1904 



immunisation consists in tlie subcutaneous inoculation of 

 some mysterious bacterial fluid prepared in the laboratory. 

 On the contrary, it is a complex process, and it is only 

 with the help of accurate scientific measuring methods that 

 the physician will be able to gauge whether he is helping 

 I r injuring his patient. B. 



PAL.^OZOIC SEED PLANTS. 

 T T may be doubted if those who are not directly concerned 

 ■'■ with the study of the vegetable kingdom appreciate 

 the full significance of the distinction which the botanist 

 maintains between plants of seed-bearing and spore-bearing 

 habit. For this reason the recent and important discoveries 

 proving that the seed-bearing habit existed among more 

 than one group of Palaeozoic vegetation, discoveries which 

 will form a historical landmark in the study of fossil plants, 

 may not attract the attention which is their due outside 

 the circle of workers on recent and fossil botany. 



The seed-bearing habit is, from many points of view, 

 regarded as a far higher stage in plant evolution than that 

 attained by any known member of the vegetable kingdom 

 in which the fertilised megasporangium remains without 

 any integument of the nature of a seed-coat. So far, the 

 botanist has associated the seed habit with two classes of 

 plants, the gymnosperms (Coniferas, Cycadeae, &c.) and 

 the angiosperms or flowering plants, and with these alone. 

 It has not been suspected that members assigned to other 

 groups, including the great race of vascular cryptogams 

 (Pteridophyta), had at any period in their evolution attained 

 to this high status. Yet such has recently been shown to 

 be the case. 



It is interesting to notice that these discoveries have been 

 mainly due to the British school of pala;obotany. .Although 

 it has been known for a long period that remains, obviously 

 of the nature of seeds, occur here and there in the sand- 

 stones and shales of the Carboniferous period, Carruthers 

 was the first to suggest, in 1872, that some of these fossil 

 seeds may be attributed to the genus Cordaites, an extinct 

 race, of gymnospermous affinities. This conclusion was sub- 

 sequently confirmed by Geinitz, Grand'Eury, Renault, and 

 other Continental botanists, who have greatly extended our 

 knowledge of this Palajozoic type. 



Until recently Cordaites has remained the solitary 

 Palaeozoic genus which was known to have attained the 

 seed-bearing habit. 



In 1901, however, Dr. Scott published a full description 

 of a Carboniferous cone, Lepidocarpon, of undoubted lyco- 

 podian affinities, where integuniented megasporangia are 

 found when fully mature, and in which each sporangium 

 contains a single embryo-sac. It has thus become clear 

 that in the history of the lycopodian stock the evolution of 

 seed-bearing members had taken place. More recently other 

 evidence has accumulated which not only confirms this con- 

 clusion, but tends to show that Lepidocarpon did not stand 

 alone among lycopods in this respect. 



It is to discoveries still more recent of a similar nature, 

 but affecting other lines of descent, that special attention 

 may be directed. They are concerned with a synthetic type 

 of Upper PaljEOzoic vegetation of great interest, which has 

 become widely known under the name Cycadofilices. 

 More than one genus of this group has now been shown 

 to have reached the seed-bearing status. 



The credit of the first discovery of this nature is due to 

 Prof. Oliver and Dr. Scott, who recently published a 

 full account of the seed and the evidence for its attribution 

 in the Philosophical Transactions of the Royal Society. 

 The more important conclusion of these authors may be 

 briefly summarised as follows. It has been found that a 

 seed, already recorded by Williamson as Lagenostoma 

 Lomaxi, was borne by the fossil plant known as Lygino- 

 dendron. The two have not been found in continuity, but 

 the evidence for this conclusion, although in the main in- 

 direct, is none the less conclusive. The chief point lies in 

 the identity of the glandular structures found on an organ 

 termed the " cupule," which envelops the seed, with those 

 already known to occur on the stems, petioles and pinnules 

 of Lyginodendron, which are peculiar to this genus among 

 Carboniferous plants. 



Within a few months of the earlier record of this re- 

 NO. 1829, VOL. 71] 



markable research by Prof. Oliver and Dr. Scott, their 

 main conclusion was confirmed in an une.xpected manner 

 by the discovery, on the part of Mr. Kidston, of the seed 

 of another genus of the same group, Medullosa, of which 

 an account has also appeared in the Philosophical Trans- 

 actions. In this case the pedicel of a large seed, of the 

 type known as Rhabdocarpus, w'as found to bear pinnules 

 identical with those of the frond Nctiroptcris heterophylla, 

 the foliage of a Medullosa. 



Here absolute continuity, an e.xtremely rare circum- 

 stance among fossil plants, exists between a foliar and a 

 reproductive organ. 



Further evidence, but more inconclusive and indirect, also 

 exists, but space forbids any notice, here. Attention may, 

 however, be directed to an interesting and suggestive com- 

 munication published by M. Grand'Eury in the Complcs 

 rcndiis during the present year on the same subject. 



The discoveries under discussion have made it clear that 

 at least two genera of the Cycadofilices possessed the seed- 

 bearing habit, and evidence is also available which suggests 

 that Lyginodendron and MedulloSa did not stand alone in 

 this respect. 



Prof. Oliver and Dr. Scott have concluded that " the 

 presence in the Palaeozoic flora of these primitive, Fern- 

 like Spermophytes, so important as a phase in the history 

 of evolution, may best be recogijised by the foundation of 

 a distinct class which may suitably be named Pterido- 

 spermea?.'* This suggestion would seem to be a happy 

 one, even though it may eventually involve the absorption 

 of the whole group now familiar as the Cycadofilices. 



In connection with these researches of Prof. Oliver, ijr. 

 Scott, and Mr. Kidston, many further points of interest, 

 and in some cases of criticism, might be discussed, but it 

 must suffice here to direct attention to one or two valuable 

 clues which these discoveries afford. The phylogeny of the 

 cycads, a race with a great past, and still existing though 

 in greatly diminished numbers, is in its main outlines now- 

 clear. There can be little doubt that the cycads are 

 sprung from this same pteridospermous stock, which in its 

 turn originated from a truly fern-like ancestor. 



In the investing envelope of the young seed of Lageno- 

 stoma, which Prof. Oliver and Dr. Scott have spoken of 

 as the " cupule," it is not improbable that homologies mav 

 eventually be recognised with protective structures exist- 

 ing among members belonging to other lines of descent, 

 which may have great value as a contribution to other 

 phylogenetic problems. 



In conclusion, the existence of the seed-bearing habit 

 among certain members of three out of the six great groups 

 of Upper Palsozoic times raises the interesting speculation 

 whether other groups may not eventually be found to have 

 attained to the same status. The Calamites, the repre- 

 sentatives of the Equisetales, are at present above anv real 

 suspicion in this respect, yet it w-ould now be hardly sur- 

 prising if further discoveries revealed the existence of seed- 

 bearing members in this group, although it is by no means 

 safe to assume that the seed-bearing habit must necessarilv 

 have existed in any group. E. A. N. Arber. 



ANTHROPOLOGICAL NOTES. 

 ■T^HE Reliquary and Illustrated Archaeologist for October 

 contains, as is usual with this journal, interesting and 

 well illustrated articles, among which may be noted one 

 on "the funambulist," or rope-walker, by Mr. Arthur 

 Watson ; some Xorman and pre-Norman remains in the 

 Dove-Dale district, by Mr. G. le Blanc Smith : medallic 

 portraits of Christ in the sixteenth century, by .Mr. G. F. 

 Hill ; a carved bone of the Viking age, bv Mr. J. Romillv 

 AUen. 



All who are interested in primitive technology will welcome- 

 the new instalment of Dr. Walter E. Roth's monograph on 

 North Queensland ethnography. Bulletin No. 7 deals with 

 domestic implements, arts, and manufactures, and is illus- 

 trated by twenty-six plates containing 250 figures. Dr. 

 Roth not only describes the objects in daily use of the 

 Queensland blacks, but, what is of very much greater im- 

 portance, he usually describes how and of what they are 

 made. Of especial interest and importance is his descrip- 

 tion of the manufacture of stone implements. He says : — 



