398 SUMMARY CF CURRENT RESEARCHES RELATING TO 



resistant seed-coats : {q) food storage in embryo ; and (r) fruit long 

 persistent on the tree. 



Anatomy of Leaves of Bromeliacese.* — E. Keiliue has studied the 

 leaves of numerous species belonging to the Bromeliacefe in order to 

 discover the relatiou between the anatomy and the mode of life of the 

 plant, and finds that there are three different types of structure. 



The first type is characteristic of plants which are wholly adapted to 

 a terrestrial habitat ; the leaves have well-developed vascular bundles in 

 which the xylem is especially prominent ; the fibres surrounding the 

 bundles are non-sclerenchymatous, and epidermal scales are rare except 

 where needed for the protection of stomata. 



The second type is characteristic of a genus in which most of the 

 species are epiphytic, but are capable of a terrestrial mode of life. In 

 this case the vascular bundles are relatively less well-developed ; the 

 fibres suiTounding the bundles are sclerenchymatous ; epidermal scales 

 are of frequent occurrence and serve the purpose of absorption ; fibres 

 also occur in the aqueous or chlorophyll tissue. 



The third type is characteristic of complete epiphytes. The leaves 

 of these plants have poorly developed vascular bundles ; the fibres 

 surrounding the Imndles are numerous and well-developed ; epidermal 

 scales are very numerous, covering the entire surface and playing an 

 important part in the work of absorption ; the epidermis itself is more 

 or less impregnated with sclerenchyma. 



In the case of JEchmea fuJ(jens it was shown by experiment that the 

 epidermal scales are present or fail to develop in response to the 

 conditions of habitat. 



Chemical and Histological Characters of Radish.f — M. Molliard 

 publishes a second paper dealing with the modifications of structure and 

 of reserve-materials resulting from placing the roots of plants in con- 

 centrated solutions of sugar. The first series of experiments made with 

 the radish showed that concentrated solutions of such sugars as glucose 

 and saccharose caused considerable alterations in the nature and con- 

 centration of sugars stored in the tissues, and that the tissues themselves 

 underwent considerable modification. The present work shows that 

 these conditions are accompanied by corresponding changes in nitro- 

 genous reserves and also bv certain distinct anatomical changes in 

 the tubercles. Similar plants were grown : (1) in ordinary soil in the 

 open air ; (2) similarly in pots in a greenhouse ; (3) in 6 p.c. solution 

 of glucose ; (4) in 10 p.c. solution of glucose ; (5) in 10 p.c. solu- 

 tion of saccharose; and (6) in 15 p.c. solution of saccharose. The 

 reserve-materials showed little difference in the first two cases, but 

 the last four experiments showed a marked increase in the total sugar- 

 reserve, more especially in the non-reducing sugars ; the amount of 

 starch was also increased, but in a smaller proportion. The solutions 

 of saccharose produced more marked results than those of glucose_ 



* Eev. Geu. Bot., xxvii. (1915) pp. 77-95 (4 figs.). 



+ Rev. Gen. Bot., xxvii. (1915) pp. 161-8 (2 pis. and 2 figs.). 



t^ 



