SECTIONAL TRANSACTIONS.— K. 405 



Dr. E, H. Moss.— The Parkland of Alberta. 



The various floral provinces of central and southern Alberta are related to climatic 

 factors and soil types. The Parkland is a broad transition or tension belt occurring 

 between the prairie on the south and the wooded areas to the north and west. It 

 consists, in its typical form, of alternating patches of prairie and aspen vegetation, 

 the prairie areas occurring on dry knolls and south-facing slopes, the poplar groves 

 being confined to depressions and north-facing slopes. Consideratioji is given to the 

 dominant grasses of the prairie association and to the chief constituents of tlie aspen 

 association. Of about 100 species of vascular species recorded from aspen groves in 

 the Parkland, only some thirty-five are regarded as constants. Amongst the various 

 factors that have influenced the invasion of trees into the prairie, burnmg is held to 

 be of greatest importance. With the settlement of large parts of the country in recent 

 j-ears, fires have been of less frequent occurrence, and consequentlj' there has been 

 a marked advance of poplar trees into the northern part of the prairie. Consideration 

 is given to the role of Symphoricarpos in initiating the advance of the aspen association 

 upon the prairie and in occupying grassland areas partially denuded by ground 

 squirrels and badgers. 



Mr. J. Stirling. — Study of the Morphology of Heterostyly. 



Dr. Macgregor Skene. — Semi-popular Lecture : Dormancy and Germi- 

 nation. 



Tuesday, September 9. 



Prof. 0. V. Darbishire. — Observations on the Protothallus of the Lichen 



Pertusaria communis (L.) D.C. 



PeHusaria communis is one of our commonest bark-loving crustaceous lichens. 

 The marginal portion or protothallus consists of the primary growing tissues, from which 

 the mature tissues of the metathallus gradually develop. The fungal hyphse of the 

 protothallus spread well in advance of the gonidial layer. The author describes how 

 new algae cells are taken in at the protothallus, gradually absorbed by the tissues of 

 the latter and finally incorporated in the gonidial layers which form the metathallus. 

 In the metathallus itself the gonidial layer spreads hy vegetative division among the 

 separate gonidia. The views of Frank and Nienburg concerning the way in which the 

 algae of the gonidial layer spread in the case of allied species, by means of ' travelling 

 algae ' and ' pushing hyphae ' respectively, are discussed and criticised. 



Mrs. N. L. Alcock. — A Phytophthora on Strawberries causiiig a Root-rot. 



A disease of strawberries has been prevalent and severe in certain parts of Scotland. 

 The root system is affected with a rot that ultimately leads to the death of the plant. 

 A Phytophthora has been found intimately and continuously associated with this 

 disease, and that this is the cause of the trouble is considered probable. 



The Phj'tophthora has sexual organs, both amphigynous and paragynous. The 

 •disease has been found to be contracted from the soil, and the oospores probably 

 hibernate and germinate there, but further experiments are in progress to determine 

 this and other points. 



Dr. W. R. IviMEY Cook. — Cystochytrium radicale, a new Species of the 

 Protista in the Roots of Veronica Beccabunga. 



The organism enters the roots as a small uniflagellate zoospore which bores its 

 way into the cells and there becomes spherical. It invests itself in a thick cyst which 

 appears to be composed of chitin. The nucleus divides, and the organism grows into 

 an elongated body still surrounded by the ej^st. The cytoplasm becomes vacuolated 

 and the greater part of the centre is filled by a vacuole. The nuclei are arranged 

 around the periphery embedded in cytoplasm ; several hundred may be present. The 

 external shape of the fungus varies very much, sometimes being irregularly curved 

 or half-moon shaped ; occasionally it gives the appearance of being branched. 



