ZOOLOGY AND BOTANY, MICROSCOPY, ETC, 401 



strand, which ends, as a rule, in the apical mamelon, or is continued on 

 into the stolon, if there be one. From this reticulate stele root-strands 

 arise without order. The fusion of strands at the apex is similar to the 

 disintegration of strands at the base. It is comparable to the transition 

 from the protostelic to the dictyostelic condition in some fern-rhizomes. 

 The gaps are not due to the influence of leaf-traces, for there are no 

 leaves at all on the tuber. The dilatation of the solid stele into a 

 hollow network may possibly be due to the necessity of supplying 

 adequate food to all parts of the tuber. The reticulate stele is unique 

 because all the gaps in it are what have technically been called 

 "perforations." 



Bryophyta. 

 (By A. Gepp.) 



Development of Certain Bryophyta.* — E. Lampa finds that similar 

 phenomena occur in certain stages of development in mosses. In a 

 few-celled protonema of Sphagnum, there arises an apical cell, as in a 

 developing fern prothallium. This forms several segments, and then 

 the whole structure increases greatly in size by means of marginal 

 meristem. The Sphagnum plant proper is developed from a marginal 

 cell of the thalloid protonema. This marginal cell is divided into two 

 by a wall. From one of these cells an apical cell is cut off, and the 

 further growth of the resulting plantlet is exactly the same as that of 

 a young liverwort, to which it l)ears a remarkable resemblance. The 

 plantlets grow^ very slowly ; possibly for that reason the flat protonemata 

 are necessary in order to increase the chances of life of the extremely 

 tender buds. The papilla-like character of the younger leaves is note- 

 worthy. 



The filamentous protonemata of Haplomitrium Hookeri are not to 

 be distinguished from those of a moss. The branching of the filament 

 is very pronounced. The early foliage much recalls that of many 

 Jungermanniaceae. The shoot-rudiment of Riccardia pinguis is very like 

 that of a moss. Researches on symbiosis with Mycorrhiza would be 

 interesting. Diphyscium foliosum develops peculiar club-shaped growths, 

 which, however, appear to have no connexion with the true moss 

 plantlet. On that point further study is needed. 



Treubia insignis.f — D. H. Campbell describes the archegonium and 

 sporophyte of TreuUa insignis, from material collected at the original 

 locality, Tjibodas, in Java. The archegonium differs from that of other 

 liverworts in having as many as nine rows of neck-cells ; and there is no 

 clear line of demarcation between neck and venter. The neck canal 

 cells did not exceed eight, though Griin has found sixteen in the mature 



* Oesterr. Bot. Zeitschr. Ixv. (1915) pp. 195-204. See also Bot. Centralbl., 

 cxxxi. (1916) p. 409. 



t Proc. Nat. Acad. Sci. U.S.A. Washington, ii. (1916) pp. .30-1. 



