Anatomy and Histology of Macrocystis pyrifera 
and Laminaria saccharina. 
BY 
M. G. SYKES, 
Girton College , Cambridge , and Bathurst Student of Newnham College , Cambridge . 
With Plates XIX, XX, and XXI, 
A S much of the previous work on the anatomy of the Laminariaceae 
has led to contradictory conclusions, it appeared desirable that some 
further investigations should be made. Since only spirit or herbarium 
material has so far been examined, very little is known about the histology 
of these plants, and Mr. Hill therefore suggested that an examination of 
material preserved by more careful methods might yield useful results. 
1 then undertook the study of some material of Macrocystis pyrifera , A g. 
and Laminaria saccharina , Lamour., which had been previously collected 
and preserved by him, and I have since pickled and examined other 
material of Laminaria saccharina. 
I wish to express my sincere thanks to Mr. Hill for so liberally placing 
his material at my disposal, and also for much help and advice throughout 
the work. This research has been carried out at the Cambridge University 
Botany School. 
I. Historical Summary. 
(a) Anatomy . 
The trumpet hyphae in the pith tissues of the Laminariaceae were 
originally discovered by Reinke l , but Wille 2 in 1885 was the first to 
describe them accurately, and to suggest that they may possess a con- 
ducting function. 
The larger sieve-tubes in Macrocystis had been noticed by J. J, Parker 
of Otago, but it remained for Will 3 to give a careful account of them with 
1 Reinke, Beitrage zur Kenntnis d. Tange. Prings. Jahr. f. w. Bot., 1876, Bd. x, p. 317. 
3 Wille, Siebhyphen bei den Algen, Ber. d. deutsch. bot. Ges., 1885 ; and Bidrag til Algernes 
Physiologiske Anatomi, Kongl. Svenska Vetens. Akad. Handl., B. xxi, No. 12, Stockholm, 1885. 
3 Will, Zur Anatomie von Macrocystis luxurians. Bot. Zeit., 1884. 
[Annals of Botany, Vol XXII, No. LXXXVI. April, 1908,1 
