86 



NA TURE 



[November 19, 1908 



by Miss E. N. Thomas, Mr. Parkin, Prof. Bower, and 

 others. 



Prof. H. H. W. Pearson, of Cape Town, contributed a 

 note on the morphology of endosperm, in which he described 

 the development of the endosperm in Welwitschia and dis- 

 cussed the homologies of this tissue with the endosperm 

 in the angiospermous embryo-sac. At an early stage of 

 development of the endosperm of Welwitschia all the cells 

 are multinucleate, while at a later stage each cell has a 

 single nucleus CPearson, Phil. Trans. K. Soc, 1906). An 

 e.Kamination of material collected in 1907 showed that the 

 latter condition is brought about by the fusion of nuclei 

 in the cells of the young endosperm. The original nucleus 

 of an embryo-sac produces by repeated division rather more 

 than 1000 nuclei ; the sac then elongates, and the free 

 nuclei are re-distributed, with the result that two regions 

 are differentiated, a micropylar region with scattered nuclei 

 and a lower region with more crowded nuclei. The sac 

 is next divided into compartments, those at the micro- 

 pylar end having two to six, and the others usually twelve 

 or more nuclei. The compartments containing more than 

 six nuclei are converted by nuclear fusion into uninucleate 

 cells ; the nuclei in the micropylar compartments remain 

 Jree, and the wall of each "cell " grows upwards into an 

 embryo-sac tube (" prothallial tube "), into which pass the 

 nuclei and cytoplasm ; these nuclei are functional gametes. 

 The conclusion is that the endosperm of Welwilschia re- 

 presents a new organism, w'hich it is proposed to call the 

 trophophylc, intercalated in the life-cycle, belonging neither 

 to the sporophyte nor to the gamctophyle. It is the opinion 

 of the author that the trophophyte of WeKvitschia is 

 phylogenetically related to the endosperm of angiosperms. 



On Tuesday Prof. Weiss read a paper on the primary 

 wood of Lepidodendron and .Stigmaria. A new Stigmaria 

 was described in which the xylem of the stele consists of 

 a central strand of long, narrow, protoxylem-like elements 

 mixed with parenchyma, surrounded by normal centrifugal 

 secondary wood. This type of stele was compared with 

 that of SelagincUa spinosa and of the " hypocolyl " of 

 5. Kraussiatia, and also with that of Lepidodendron 

 selaginoidcs. The general relations of the steles of the 

 Lcpidodendrea^ were discussed. 



Mr. H. H. Thomas communicated a paper by Mr. 

 Xewell .Arber and himself on the structure of Sigitlaria 

 scutellata, Brongn. This was the first full account of the 

 structure of a Sigillarian stem of the Rhytidolepis tvpe. 

 The primary xylem of the stele forms a continuous ring 

 of scalariform tracheids surrounding the medulla. 

 .Secondary xylem is also present. The characteristic 

 external ribs are really formed of cortical tissue, 

 not of fused leaf-bases, and are largelv composed of phello- 

 derm. A ligule in its pit was demonstrated for the first 

 time. The leaf-trace in the leaf-base contains a double 

 xylem strand with widely separated xylem groups of the 

 Sigillariopsis type. 



Mrs. D. H. Scott described some curious spindle-shaped 

 bodies in Burntisland material, naming them ISensonitcs 

 fusiformis. She inclined to the view that thev are glandular 

 structures belonging to Stauropteris htirntislandica, with 

 which they are associated. A sporangium of this species 

 was found to contain germinating spores. 



Miscellaneous Papers. 



On Thursday Colonel H. E. Rawson contributed a 

 striking account of colour changes in flowers produced by 

 controlling insolation. He has found that by shading 

 various plants (such as nasturtiums) from the direct rays 

 of the sun during certain hours of the day the colours of 

 the flowers produced are changed from scarlet and orange 

 to mauve, and in other cases to deep carmine. The varia- 

 tions thus produced breed true, both from cuttings and 

 seeds. In other in.stances bronze, old-gold, rose-salmon, 

 and sallow flesh-coloured flowers have been produced by 

 similar means. Dahlias and other flowers appear to be as 

 susceptible as nasturtiums to this treatment. 



Mr. W. L. Balls contributed two papers on the 

 mechanism of mitosis and on the natural crossing of the 

 cotton plant. 



Mrs. D. H. Scott read a paper on the contr.actile roots 

 of the aroid Sauromalum giitlalnni, in which she showed 

 Ihat if the tuber of this pl.-."i is planted on the surface 



NO. 2038, VOL. 71)] 



of the soil it throws out leaves and subsequently disappears 

 below the surface, and in two months' time is found at 

 a depth of b inches. The descent is caused by the thick 

 fleshy roots sent out from the upper surface of the tuber, 

 which firmly attach themselves to various objects in the 

 soil, and then contract lo about half their origmal length, 

 pulling the tuber down. Later on these contractile roots 

 are cut off from the tuber by regular alseris layers. If 

 the tuber is replaced on the surface it sends out a fresh 

 set of contractile roots, and is again pulled down to the 

 normal depth. 



Mr. M. Wilson contributed notes on the life-history of 

 Haematococciis lacustris, in which he described the results 

 of various culture experiments on this species. The red 

 cells were found to be produced in starved liquid cultures, 

 and to be alone capable of withstanding the effects of dry- 

 ing. Dr. Lotsy contributed an interesting paper on the 

 segregation of characters of a perfectly fertile species- 

 hybrid. 



Mr. Harold Wager made a contribution on the optical 

 behaviour of the epidermal cells of leaves. He discussed 

 Haberlandt's theory that the convergence of light rays 

 brought about by the lens structure formed by the papilhe 

 of the epidermal cells of many leaves brings about a differ- 

 ential illumination of the protoplasm on the basal wall, 

 and thus creates a stimulus which results in the appropriate 

 orientation of the leaf to the incident light. It was pointed 

 out that the objcclion to this theory, based on the ab.sencp 

 of epidermal lens papillae from heliotropically sensitive 

 grass-seedlings, may be met by the fact that the epidermal 

 cells of the first (sheathing) leaf and of the young leaves 

 enclosed in the sheath do actually cause convergence of 

 light rays in spite of the absence of papillee. In the 

 author's opinion loo little attention has been paid to the 

 view that the lens structures in question may be concerned 

 with the more efficient illumination of the chloroplasts. 

 It is also possible that the structures in question are 

 accidental, and not to be regarded as adaptations, since 

 they also occur on the lower epidermis of various leaves, 

 on the epidermis of some petals, and in the fungus Russula. 

 Mr. W'ager exhibited well-defined photographs of various 

 objects made through these epidermal lenses. 



Monday morning was devoted to a joint discussion with 

 Section D on the determination of sex. J"his is reported 

 in the article on " Zoology at the Brit' '1 Association " 

 (Nature, October 22, vol. Ixxviii., p. 647). 



Members of Section K were fortunate in being able tn 

 meet in Prof. H. H. Dixon's beautiful new botanic:iI 

 institute at Trinity College, where everything was arrangeil 

 for their comfort and convenience. 



The sectional excursion was held on the Saturday lo Ih ■ 

 Murrough of Wicklow, a long stretch of shingle beacli 

 backed by marsh, under the leadership of Mr. R. Lloyd 

 Praeger. 



MR. LLOYD GEORGE ON THE EN DOW M EXT 



OF UNIVERSITIES. 

 /^ \ Xovember 13 the University of Wales conferred 

 ^'^ the degree of Doctor of Laws, honoris causa, on 

 .Mr. Lloyd George. At the complimentary banquet given 

 by the University College of North Wales, Lord Kenyoji 

 announced a donation of 1000/. from Sir Herbert Roberts 

 to the college building fund. In replying to the toast in 

 his honour. Dr. Lloyd George alluded to the sacrifices the 

 Welsh people have made in building up their system of 

 higher education, and pointed out that the University of 

 Wales has entirely altered the status of the Welsh people. 

 It would be the w'orst thing for the Government to take 

 the task entirely out of their hands, but the time ha- 

 arrived for the Government to render further assistance, 

 and one great need of the colleges is a very common- 

 place one — cash. Further assistance of a substantial 

 character would make a vast difference in the immediate 

 prospects. One of the ablest committees has investigated 

 the claims of the Welsh colleges, and the conclusions 

 arrived at are very favourable. The committee indicated 

 several directions in which more could be done if the 

 colleges had more monev. 



Dr. Lloyd George had to consider the report of the com- 

 mittee, and it was his dutv as Chancellor of the 



