fe 
1905] CURRENT LITERATURE 71 
No general uniformity exists in regard to the branching, although two general 
may be separated: (1) the cymose, (2) the racemose. The leaves show 
considerable similarity in outline. Two type groups are made, the narrow leaved 
and the broad leaved type. The former type occurs only on species whose leaf- 
bearing branches are short and upright, while the broad leaves occur only on 
those whose branches are long 
In regard to protection of aids there is a considerable uniformity. Rhizo- 
phora, Bruguiera, Ceriops, Kandelia, and Scyphiphora are protected by means 
of axillary leaves which surround the developing parts; Aegiceras and Xylocarpus 
by means of true bud scales; Lumnitzera by red fleshy bud scales; Avicennia 
and Sonneratia by means of depressions in the leaf stalks. In comparison with 
northern trees, therefore, it will be seen that the majority of mangroves have 
buds similar to summer buds (Platanus), while Aegiceras and Xylocarpus cor- 
respond in this respect to the winter buds of northern latitudes. 
The author criticises A ’s work on the anatomy of mangrove leaves,?° 
in that the latter author has not studied the plants in nature and his theory that 
salt-secreting hydathodes are general among mangroves is not proven in nature. 
at salt-secreting glands do occur is definitely proven, but only in the one 
genus Aegiceras.—G. H. JENSEN. 
THE FINAL paper of BLracKMANn’s studies on the fertilization, alternation of 
generations,-and general cytology of the Uredineae has appeared,"! presenting the 
subject more fully than the preliminary account which was reviewed in our 
April number.'?, We shall note at this time simply some additional details in 
this very clear and interesting paper. 
The structure of the nuclei and processes of mitosis were studied, but it is 
evident that these subjects are very difficult. The chromatin remains for the 
most part in masses, so that chromosomes cannot be counted; but of course while 
there is but one mass throughout the gametophyte history from the teleutospore 
to the aecidium, there are two in the paired nuclei of the sporophyte. The 
nucleolus, always present, is extruded with each mitosis and formed anew in the 
daughter nuclei. A rudimentary spindle can sometimes be observed, with 
bodies at the poles which BLACKMAN calls centrosomes and which he believes 
arise by division, but his evidence seems insufficient on the latter point. The 
“conjugate” method of division of the paired nuclei only differs from that of 
single nuclei in the fact that two divide simultaneously side by side. The daughter 
nuclei remain entirely apart, so that the continuity of the chromatic material is not 
broken until the fusion in the teleutospore. 
LACKMAN points out the exact agreement of certain conditions in the Basidio- 
mycetes with those in the Uredinales. Thus the mycelium preceding the basidium 
10 Bibliotheca Botanica, heft 56. 
11 BLACKMAN, V. H., On the fertilization, alternation of generations, and general 
cytology of the Uredineae. Ann. Botany 18: 323-373. pls. 21-24. 1904 
12 Bot. GAz. 37:320. 1904. 
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