1908] CURRENT LITERATURE ‘ 153 
cicle appeared in 1900, so that four to eight years have elapsed since the various 
parts appeared. During this period the author says that local and visiting 
botanists have been extremely active in exploration, discovering new stations, 
plants new to Greece, and new: species. All these additions have been brought 
together in this supplement, so that the Conspectus may be regarded as fairly 
complete again.—J. M. C. 
Anatomy of dicotyledons.—The translation of the SOLEREDER’s Systematische 
Anatomie der Dicotyledonen'3 into English gave the author opportunity to revise 
the work and to add much supplementary matter. This has now been brought 
together at the instance of the German publisher for the benefit of those who have 
the original. This large Erganzungsband will be desirable for all those libraries 
that have the first two volumes, for it contains an immense amount of material. 
Besides the additional data, the concluding remarks have necessarily been revised. 
mae Se ae CB 
NOTES FOR STUDENTS 
Sieve tubes in Laminariales.—Miss SyKEs"™ has investigated the anatomy 
and histology of Macrocystis and Laminaria, chiefly M. pyrifera and L. saccharina. 
A few other species, such as Sacchariza bu osa, Laminaria digitata, Alaria escu- 
lenta, and N ereocystis Luetkeana, were also examined to supplement the main 
tesults. Chief attention was paid to the morphological nature of the trumpet 
hyphae and of the true sieve tubes, the presence or absence of protoplasmic con- 
necting threads, the development of sieve plates, and the nature of callus. 
Some of the conclusions may be summarized as follows: (1) The trumpet 
hyphae in M. pyrifera and L. saccharina are to be looked upon as true sieve tubes. 
They represent the original central cells of the thallus modified, and may be termed 
primary pith filaments. Though they differ as to their degree of development, 
they are certainly homologous with the secondary sieve tubes of Macrocystis, 
paper ete similarly derived from the modified primary cortex of the young thallus. 
(2) It is believed that the histology of the sieve plates in the primary pith fila- 
ments and secondary sieve tubes is essentially the same. Threads are formed 
ee nn the young sieve plates, and each gives rise in the older plate, apparently 
¥ means of ferment action, to a slime string inclosed in a rod of callus. In 
__toeystis each original thread first divides to form a group, and each thread of 
* group forms its own callus rod, but finally, by fusion, only one slime string is 
ei | from each group. The older sieve plates are obliterated by the depos 
ait, @ 'arge mass of callus over their surface, and callus is also formed through- 
€ length of the old sieve tubes. (3) The callus is to be looked upon as a 
I ere 
*3 SOLE 
fir Labora 
Imp. 8vo 
REDER, H., Systematische Anatomie der Dicotyledonen. Ein Handbuch 
orien der wissenschaftlichen und angewandten Botanik. Erganzungsband. 
i * PP. vili+422. Stuttgart: Ferdinand Enke. 1908 vs 
—_c » M. G., Anatomy and histology of Macrocystis pyrifera and Laminaria 
- Annals of Botany 22: 291-325. pls. 19-21. 1908. 
