﻿THE DEVELOPMENT OF THE CONCEPTACLE IN FUCUS 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 212 



Mabel Lewis Roe 

 (WITH PLATES XIV-XVIl) 



Introduction 



When engaged upon a study of Splachnidium rugosum, the 

 writer was forced to work out a new theory for the development 

 of the conceptacle, since methods previously described did not 

 offer sufficient explanation for what was found in Splachnidium. 

 It seemed probable that such might also be the case in more 

 advanced members of the Fucaceae, particularly Fucus, and it 

 was with this in mind that a re-examination of this well-known form 

 was undertaken. The results have proved interesting enough to 

 warrant the reinvestigation. 



Material and methods 



For the material the writer is greatly indebted to Professor 

 Charles J. Chamberlain, who had at his disposal paraffin cakes 

 of young tips of Fucus edentatus Delapyl. and Kjellman {F. furcatus 

 Agardh et al.) and of Fucus vesiculosus L., of which he had also 

 mature tips containing ripe conceptacles. In addition, he fur- 

 nished the writer entire plants of Splachnidium rugosum Grev., 

 collected by him at Glen Cairn, near Cape Town, South Africa. 

 To Professor John M. Coulter the writer is indebted for material 

 of Fucus serratus L., which was collected at Pictou, N.S., by Mr. 

 J. Crerar McDonald, at the request of Professor W. G. Farlow. 

 All the material, except that used for fig. 20, was cut 5-8 n in thick- 

 ness, parallel to the long axis and at right angles to the flat surface 

 of the thallus. Material for fig. 20 was cut 15 n thick. The 

 sections were stained with Haidenhain's iron alum haematoxylin 

 and given a light touch before mounting with Grtibler's Lichtgriin 

 dissolved in equal parts of absolute alcohol and clove oil. The 

 former stain brought out nuclear and cytoplasmic detail, while the 

 latter gave in sharp relief all cell walls and layers of mucilage. 

 231] [Botanical Gazette, vol. 61 



