396 SUMMAEY OF CURRENT RESEARCHES RELATING TO 



to the oldest walls. The three-sided g^rowing point of the leaf arises in 

 the dorsal half of a middle story of a dorsal stem-segment. It is 

 formed when the segment consists of four stories, and takes up an 

 eighth of the segment-surface. The apical cell of the leaf lies with the 

 longitudinal axis of its basal surface obliquely to the longitudinal direc- 

 tion of the shoot. After the formation of the lamina the apical cell of 

 the leaf of Marsilia divides by a periclinal wall and is thus put out of 

 action. This was not observed in Pilularia. The lateral branch arises 

 from the ventral half of those dorsal segments, which also form a leaf. 

 It is developed at the same level as the leaf. The roots are formed 

 from the ventral segments, alternately right and left of the medium 

 ones. The root-mother-cell is formed when the segment consists of 

 four stories, from one of the middle stories. 



Root-structure of Azolla.* — G. Chauveaud, writing in correction 

 of a statement recently made by C. Queva about the structure of the 

 roots of AzoUa /ilicidoides, shows that it really belongs to the general 

 type, and possesses two strands formed each of a single sieve-tube alter- 

 nating with two vascular strands. In each of the latter are two vessels 

 very unequal in size and in time of differentiation. The smaller vessel 

 is formed very early, and is liable to be crushed and obliterated by the 

 larger vessel, which is differentiated later. Hence the smaller primary 

 vessel has escaped the notice of Van Tieghem and other workers. 



Reduction of the Suspensor in Selaginella.f — H. Bruchmann 

 continues his investigations of the embryology of SelagineUa. In a 

 previous paper he described the reduction of the suspensor of S. Galeottei, 

 a phenomenon till then unrecognized in the genus ; and in the present 

 paper he gives the result of his examination of S. Kraussiana and S. 

 Foulteri. In both these species he finds that the suspensor is unde- 

 veloped, and its function is performed by an embryo-tube. The various 

 stages of this development are described and figured. Incidentally the 

 author states that the plant advertised for sale in several of the cata- 

 logues of University Gardens as SelagineUa stolonifera Spring is not 

 rightly determined, but belongs to the group of S. Martensii. 



Fossil SelagineUa in Sussex. J — A. C. Seward describes and 

 figures the remains of a new British fossil SelagineUa — Selaginellites 

 Datvsoni — found in the Wealden Clay near Hastings. The structures 

 described are the microspores, megaspores, sterile and fertile shoots. 

 The plant may have been related to SelagineUa rupestris. The size and 

 sculpture of the spores recall *S'. serpens^ S. canaliculata, and others. 



Drymotsenium Nakaii.§ — B. Hayata describes and figures the 

 structural peculiarities of Drymotsenium Nakaii^ a new species from 

 Formosa, of a hitherto monotypic genus created by T. Makino in 1901. 

 It differs from Vittaria in its articulated fronds and anastomosing veins, 



* Bull. Soc. Bot. France, Iviii. (1911) pp. 79-82 (figs.). 



t Flora, V. (1913) pp. 337-46 (figs.). 



i New Phytologist, xii. (1913) pp. 85-9 (1 pL). 



§ Bull. Soc. Bot. France, Iviii. (1911) pp. 563-6 (pi. and figs.). 



