408 SECTIONAL TRANSACTIONS.— K. 



thirty varieties studied, edible and ornamental, not one shows perfect pairing of 

 chromosomes at maturation, most being aneuploid. In those with higher numbers — 

 sour cherries and ' Dukes ' — the phenomena of tetraploidy are clearly exhibited. 



It appears that the three groups, sour, sweet, and ' Dukes,' have been obtained 

 by rearrangement, within the possible limits, of the three, partially homologous, 

 series of chromosomes, two contributed by Prunus cerasus and one by P. avium. 

 The conclusion reached, that all existing kinds of domestic cherries owe their origin 

 to hybridisation of the parent species, is strengthened by morphological considerations. 



13. Mr. R. J. Chittenden. — The Inheritance of Chlorophyll Aberrations 



in Pelargonium. 



Chlorophyll aberrations, though similar phenotypicaUy, may show either simple 

 Mendelian inheritance or non-Mendelian bi-parental plastid inheritance in which 

 somatic segregation of the parental character occurs in the Fi plants. In the non- 

 Mendelian cases the phenotypic appearance is due to the plastids alone. The genetic 

 character of the nuclei is masked, but can be ascertained by suitable crosses with 

 Mendelian varieties, when — allowing for the occurrence of variegation and whole- 

 coloured seedlings of that tissue type known to be due to plastid inheritance — the 

 nature of the nucleus can be determined by the types of segregates represented in the 

 progeny. 



14. Dr. H. HoLDEN. — Observations on the Morphology of Ankyropteris 



Corrugata. 



Ankyropteris corrugata is a small zygopterid fern with a stem stele which is 

 cylindrical except where its symmetry is disturbed by the departure of leaf-traces. 

 The petioles are given ofi in two series and branch dichotomously. Both stem and 

 petioles bear aphlebise which appear to have been protective in character. Three 

 types of hair are borne by the petioles and aphlebise, namely : (a) Delicate branched 

 ones, (6) stout hispid ones, (c) large hairs with dilated bases Tvhich suggest an early 

 stage in the evolution of ramenta. 



Saturday, August 7. 



Excursion to the Berkshire Downs. 



Sunday, August 8. 



Afternoon. 

 Excursion (with Sub-section K*) to Bagley Wood. 



Monday, August 9. 



15. Dr. H. Wager, F.R.S. — Carbon Assimilation in the Blue-green Algoe. 



Since the discovery, by Errera, many years ago of the existence of glycogen in 

 the cells of species of the blue-green algoe, evidence has been brought forward to show 

 that in this group of plants glycogen is probably a product of carbon assimilation. 

 In the present paper this evidence is summarised, and further experiments, including 

 the growth of specimens under different coloured-Ught filters, both in the presence 

 and absence of light and carbon dioxide, all of which tend to support this conclusion, 

 are described. The spectroscopic examination of various species also shows that, in 

 relation to the formation of glycogen, the light rays absorbed by the phycocyanin 

 colouring matters, as well as those absorbed by the chlorophyll, are concerned in the 

 process. 



1 6 . Dr. W. Brown and Miss C. C. Harvey. — On the Resistance of the 



Cuticle to Penetration by Fungal Hyphce. 



The failure to demonstrate the presence of any cuticle-dissolving substance and 

 the evidence derived from experiments with artificial!}' prepared membranes show 



