460 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Structure and Development. 

 Vegetative and Reproductive. 



Embryogeny of the Cruciferae.* — R. Soueges contributes a note 

 dealing with bis study of the development of the embryo in the 

 Crnciferse. The author has studied the embryos of several species 

 of Lepidium and also of Cochlear la officinalis, and is led to the conclusion 

 that modern investigators are wrong in their descriptions of tbe earlier 

 stages of the embryo-formation in the Craciierae ; it would rather seem 

 that earlier authors were correct when they stated that the cells of the 

 quadrant were disposed in a horizontal plane and were separated by two 

 longitudinal walls. Subsequent to the formation of the first transverse 

 wall the embryo is differentiated into a hypocotyl and cotyledons ; the 

 dermatogen is the result of a series of divisions parallel to the surface. 

 The periblem and plerome of the hypocotyl develop as the result of two 

 vertical divisions. The cotyledons grow at the expense of two cortical 

 layers situated between the epidermis and the central axis, the cell-walls 

 being formed always in a radial direction, thus differing from the 

 adjacent tissues, in which cell-walls are formed in all directions. The 

 origin of the hypophysis cannot be traced with certainty, but it appears 

 to arise from certain cells which are adjacent to the lateral walls of the 

 dermatogen ; the four upper cells constitute the initial -cells of the cork, 

 and the four lower cells divide once tangentially to form the initial-cells 

 of the epidermis of the root-tip. 



Fertilization and Embryology in (Enothera.f — 0. Renner has 

 studied the seeds and embryos obtained as the result of crossing several 

 species of CEnoth&ra, viz. 0. biennis x muricata, 0. muricata x biennis, 

 0. biennis x Lamarckiana, 0. Lamarckiana x biennis, etc. In all 

 cases double fertilization was normal and there were fourteen chromo- 

 somes. The seeds obtained from 0. biennis x muricata and from 

 0. biennis x Lamarckiana were pure and fertile, those from 0. Lamarck- 

 iana x biennis were 50 p.c. sterile ; thus the reciprocal cross gives rise 

 to twin-hybrids, but only one, i.e. that equivalent to the veluiina type 

 develops, while the other speedily dies. The seeds from 0. muricata 

 (Venedig) x biennis produced feeble embryos and endosperm, which soon 

 ceased to develop ; the sterile seeds had a normal testa. 0. Lamarckiana 

 when self-fertilized gave at least 50 p.c. sterile seeds. The persistent 



* Comptes Rendus, clviii. (1914) pp. 1356-59. 

 t Flora, vii. (1914) pp. 115-50 (2 pis. and 15 figs.) 



