BOTANICAL SOCIETY OF EDINBURGH. 567 



branches to enter into its composition. G. tenax is also 

 characterised by the fact that, as in G. ccrvicornis, very 

 numerous rhizoids spring from the frequently uneven inner 

 limit of the thallus wall, are directed toveards the interior 

 of the thallus, and finally ensheath the central axis in a 

 rather close felt.^ 



My search after fruiting specimens of G. icnao: was, 

 however, finally crowned with success. 



In August 1892 1 found in the Herbarium of the lioyal 

 Botanic Garden, Edinburgh, on the sheet " ex herb. 

 Greville," in the cover " Gioiopdtis tenax," two small plants 

 which bore the inscription " Fucus tenax, Turn., ab ipso 

 Turner, e China. Mertens, 1829." These two specimens, 

 therefore, originated from Turner himself, and may be 

 assumed, from the foregoing, to be true G. tenax. Thick, 

 strongly projecting " cystocarps," like those in Turner's 

 figure, were not, it is true, found on these specimens. The 

 most careful examination with a lens only revealed, in the 

 dry alga, quite small elevations distributed over the surface 

 of the upper branches of the thallus. However, the micro- 

 scopic examination left no doubt of the occurrence of true 

 cystocarps. 



I found in the small branchlets which I examined 

 procarps and cystocarps in process of ripening quite similar 

 in structure to those of G. ccrvicornis. The procarps which 

 arise from the lower cells of the wall-forming filaments, 

 and project towards the outside of the thallus, show 

 individually a form quite analogous to that formerly 

 observed in the procarp of G. ccrvicornis, G. capillar is, 

 G. fiircata, and G. dura. They are distributed on the 

 limit between the wall of the thallus and the inner space 

 of the shoot, sometimes extending further into the former, 

 sometimes more immersed in the latter, but always imbedded 

 in the mucilage of the wall. The mature gonimoblast also 

 shows a formation which is quite analogous to that of the 

 gonimoblasts of the previously observed species. Through- 

 out very small, they cause the superincumbent walls of the 

 thallus to project outwards in a scarcely perceptible manner, 

 but, on the other hand, they project to a greater or less 



^ Compare Suringar's statements on the anatomical structure of G. 

 tenax in lUustr., pp. 32, 33, pi. xvii. 



