SECTIONAL TRANSACTIONS.— K. 415 



Ectocarpales as delimited by Oltmanns. The life-cycle in these forms, 

 apart from a limited number of exceptional types, is to be regarded as 

 comprising an alternation between diploid and haploid phases, isomorphic 

 in the simpler filamentous types, heteromorphic as a rule in the more 

 advanced forms. The diploid phase in the latter is constituted by the 

 elaborate macroscopic thallus which bears either unilocular sporangia only 

 or plurilocular ones as well, the latter being then most commonly produced 

 at an earlier stage than the unilocular sporangia. The haploid phase is a 

 small filamentous plant bearing plurilocular sporangia (i.e. gametangia) 

 only. Either phase can propagate for several generations by means of small 

 ectocarpoid stages, the diploid one doing so by means of the swarmers from 

 the plurilocular sporangia which give rise to plethysmothalli (using Sauva- 

 geau's term in this sense only), the haploid one by means of apogamously 

 developing gametes which give rise to accessory gametophytes (not plethys- 

 mothalli). The plethysmothalli as above defined are to be regarded as 

 arrested (juvenile) stages of the sporophyte whose general resemblance to the 

 haploid phases is a result of the derivation of the two generations from the 

 isomorphic or homologous type of alternation seen in the simpler representa- 

 tives (Ectocarpaceae) of the group. The succession of plants formed from 

 the diploid swarmers of the plurilocular sporangia of an Ectocarpus siliculosus 

 or other simple type are the equivalents of the plethysmothalli of the higher 

 forms. How far the life-cycle above indicated can be short-circuited by the 

 fusion of swarmers from the unilocular sporangia remains to be seen. 



Prof. Dame Helen Gwynne-Vaughan, G.B.E., and Mrs. Q. E. Broad- 

 head. — Methods of reproduction in Ceratostomella fimbriata, the 

 cause of mouldy rot of the Para rubber tree (11.40). 



This fungus is self compatible with a mycelium of uninucleate cells, 

 bearing chlamydospores and endoconidia, both of which germinate readily. 



The perithecium has two zones of wall cells and an internal lining of 

 turgid cells forming a cushion. The neck arises from the inner zone of 

 the wall ; it is made up of thick walled, parallel hyphae, lined by delicate 

 filaments. 



The ascogenous hyp has arise from a multinucleate cell. No antheridium 

 is present and development is apogamous, the only nuclear fusion being 

 that in the ascus. The haploid number of chromosomes is three, there are 

 three gemini in the prophase of meiosis which is the only reduction phase 

 in this life history. 



Prof. B. Nemec. — Gold and other rare elements in plants (12.20). 



On analysing ashes of seeds and seedlings of corn from Oslany (West- 

 slovakia) we found in the ash some elements until now only rarely discovered 

 in plants, such as gold and titanium. This discovery led to the study of 

 the ashes of other plants from the same locality. In Equisetum, gold has 

 been found in comparatively large amounts, and in the wood of Fagus, 

 Carpinus and other species, in addition to gold, aluminium, titanium, 

 copper, zinc, vanadium and chromium have been found. We have found 

 the same elements in Polyporus fomentarius growing on Fagus and Carpinus. 



Cultures of corn seedlings have shown that gold has a slight stimulating 

 effect upon growth. 



Afternoon. 

 Excursion to Garstang district. 



