356 



NATURE 



[November 25, 1915 



culated. Such data, graphically represented, showed 

 in a striking way correlations between flowering, fruit- 

 ing, and growth, which might enable an expert to 

 issue at frequent intervals valuable reports and trust- 

 worthy forecasts that would have a steadying effect on 

 the market. The lecturer also indicated how careful 

 breeding and selection of pure strains could result in 

 improved spinning quality. Pure strains yield more 

 uniform lint, which will spin well even in cases 

 where the expert grader would reject a sample at first 

 sight as worthless. The need of closer co-ordination 

 between the grower and spinner was emphasised, the 

 chief desideratum being a common language, which 

 might be provided by men of science, so that the 

 spinner could make his requirements intelligible to 

 the grower. 



Cryptogams. 



Prof. F. O. Bower gave an account of the progress 

 which has been made since the publication of his 

 "Origin of a Land Flora" in the study of the rela- 

 tionships of the Filicales, with special reference to 

 the Dipterids and Pterideae. While dealing with these 

 in detail he gave a general account of the present state 

 of knowledge with regard to the phylesis of the ferns 

 as a whole. Members of the section appreciated the 

 opportunity of learning the direction in which inves- 

 tigations still in progress at Glasgow were pointing. 



Prof. T. G. B. Osborn sent a paper describing the 

 morphology and structure of Selaginella tiliginosa, 

 which occurs in eastern Australia. It has a well- 

 developed rhizome in which the vascular system is 

 solenostelic, with ramular gaps, a second example of 

 solenostely in the genus. In relation to this Mr. H. B. 

 Speakman demonstrated the structure of the branch- 

 ing rhizome in SelagineUa lyallii. 



Prof. A. H. R. Buller described the discharge of 

 spores from the basidia of Uredineae and Hymeno- 

 mycetes. The discharge is violent, a drop of fluid 

 being previously excreted just below the spore, and 

 discharged with it. In many cases the basidia are 

 curved so as to direct the spores towards the open air. 

 Dr. M. Wilson recorded the occurrence of the conidial 

 stage of Tuburcinia priniulicola on Primula vulgaris 

 in Kent. The conidia appear as meal-like masses, 

 partially filling the corolla tube and gluing the 

 stamens together. Conidia may be found in all stages 

 of conjugation by short connecting tubes. Germ tubes 

 are afterwards produced, which probably develop the 

 mycelium that bears the chlamydospores. These arise 

 in groups from coiled masses of hyphee, and when 

 young contain conjugate nuclei which afterwards fuse. 

 Finally, the whole ovary disintegrates, setting free the 

 spores as a black powder. Mr. W. Robinson demon- 

 strated germ tubes of certain Uredineae, and abnormal 

 spermogonia. 



Fossil Botany. 



Dr. Marie C. Stopes gave an account of the remark- 

 able flora of the Lower Greensand deposits of Aptian 

 age, represented by petrifactions, often beautifully pre- 

 served, as was amply demonstrated by lantern-slides 

 and actual sections. The flora included Cycadophyta, 

 Conifers, and woody Angiosperms. The wood gives 

 evidence of well-marked seasons, pointing to a cool 

 climate, in marked contrast to the " tropical climate " 

 inferred to have existed at the time of the Wealden 

 flora of southern England. 



Prof. F. W. Oliver showed slides illustrating the 

 structure of the seed Gnetopsis, which he has recently 

 further elucidated, and dealt with some general 

 problems of the seed and the flower. Prof. D. Ellis 

 described fungal hyphae occurring in ferruginous rocks 

 of the Lower Lias, which were incrusted with ferric 

 hydrate, unseptate, with branches, frequently in 



NO. 2404, VOL. 96] 



whorls, and spherical sporangia, each containing about 

 four spores. Another similar fungus, from secondary 

 rocks in north-west Scotland, had a hard black mem 

 brane and no sporangia. In fossilised putrefying 

 animal remains were found two Bacilli, a Micrococcus 

 and an Actinomyces-like form, consisting of a thick 

 meshwork of minute threads. 



A paper was contributed by Mrs. Edith M. Osborn 

 describing an Australian Zygopteris, probably of Uppci 

 Devonian age. This new type is of extraordinary 

 interest. It combines the main features of the Ankyro- 

 pteris grayi type of stele, with the simple Clepsy- 

 dropsoid type of petiolar structure. Axillary branches 

 were not present. Miss N. Bancroft demonstrated 

 sections showing the structure of the stem and petiole 

 and the mode of branching of Rachiopteris cyliudrica. 



Physiology. 



Miss T. L. Prankerd described observations, similar 

 to those of Haberlandt and Nemec, on the coincidence 

 in time and place of geotropic sensitivity and the 

 occurrence of movable starch grains ("statoliths") in 

 certain Liverworts and other plants, illustrated by 

 good microphotographs. Movable starch was located 

 in the top point of the curve of young circinnate 

 fern fronds. In general the nuclei of the " statocytes " 

 were larger than those of neighbouring cells, and in 

 many cases were found among the starch grains at 

 the bottom of the cells. 



Dr. Sarah M. Baker directed attention to the 

 enormous fund of energy represented by the total 

 internal liquid pressure of water (corresponding to the 

 pressure of a gas, due to molecular bombardments), 

 which, according to Van der Waals and Stefan, 

 reaches many thousands of atmospheres at low tem- 

 peratures. Just as osmotic pressure becomes effective 

 in presence of a semi-permeable membrane, so might 

 liquid pressure theoretically become effective, given 

 a membrane permeable to water vapour, but not to 

 liquid water. Dr. Baker suggested that this liquid 

 pressure might account for the ascent of water in tall 

 trees, adducing as evidence of the existence, in the 

 growing region of the root, of a membrane with the 

 requisite properties, (i) that certain dyes do not enter 

 this region, in contrast with the root-cap and root- 

 hairs, and (2) that in a moist atmosphere acid drops 

 of water exude from the root-hairs. The interpreta- 

 tion placed upon these facts was received with some 

 scepticism ; it was, moreover, objected that the rela- 

 tively low values hitherto obtained for root-pressures 

 and the existence of "negative" pressures in the 

 trunks of trees during active transpiration make it 

 abundantly evident that the pumping activity of the 

 root, however it may be explained, is not adequate 

 to the raising of water as fast as the shoot-system 

 actually absorbs and transpires it. On the other hand, 

 attention was directed to the desirability of more ex- 

 tended observations of root-pressures in relation to the 

 heights reached by different species. 



Dr. E. M. Delf gave a preliminary account of very 

 careful experiments by a new method on the effect of 

 temperature on the permeability of protoplasm. The 

 rate of contraction (proportional to the rate of ex- 

 osmosis of water) of strips of plant tissue was followed 

 minutely, and the rate at a specified stage of the con- 

 traction was taken as a relative measure of the per- 

 meability to water. The results showed a much 

 greater rate of increase at high temperatures than 

 hitherto observed, the curve being logarithmic in form 

 right up to 42°. 



Mr. A. M. Smith dealt with the effect of drying on 

 the respiration of plant organs. His experiments 

 showed that with the removal of increasing percentages 



