4li SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Structure and Development. 

 Vegetative. 



Leaf-anatomy of Andropogon.* — E. Breakwell lias studied the leaf- 

 anatomy of several species of Andropogon indigenous to New South 

 Wales, with special reference to similarities or differences in the structure 

 associated with the habit or habitat. From an anatomical standpoint 

 the species fall into three groups: Group 1 including A. intermedins, 

 A. affinis, and A. sericeus -. group 2 including A. Tschsemum : and 

 group 3 including A. refract us and A. bombycimis. 



Group 1 is characterized as a whole by well-developed sclerenchyma. 

 but A. intermedins shows well-defined structural differences from the 

 other two species. The primary bundles of the midrib are more 

 numerous, while there is also a larger number of secondary bundles 

 accompanied by a corresponding increase in sclerenchyma. A. sericeus 

 has the largest amount of sclerenchyma and serves as a connecting link 

 with group 2, which has a much greater amount of this tissue, a thicker 

 cuticle and more numerous and densely crowded vascular bundles. 

 Group 3 shows extreme development of sclerenchyma and great thicken- 

 ing of the cuticle, while the stomata are in grooves on the lower surface, 

 an arrangement not found in either of the other groups. Ecological 

 characteristics are most marked in this group ; in addition to other 

 characters mentioned above, each of the species has water-storage tissue 

 near the upper surface and the "girdle-canals" of A. bombycinm are 

 probably useful in reducing transpiration. The habitat of these species 

 corresponds with the sclerophytic characters. A. Ischseirmm is inter- 

 mediate between the species of group 1 and those of group 2, both as 

 regards habitat and xerophytic characters. All the species of group 1 

 appear to be mesophytic both in structure and habitat. 



Xerophilous Characters of Hakea.f — A. G. Hamilton has studied 

 the morphological and anatomical characters of Halcea dactyloides, a 

 shrub found in sandy regions and on the Hawkesbury Sandstone near 

 Sydney. The stems are tough and woody and covered with hairs, while 

 the vascular bundles contain numerous stout-walled fibres. The leaves 

 are few, arranged spirally and vertically, and the size varies according to 

 the season ; there are three main veins and another of smaller size 



* Proc Linn. Soc. N.S.W.. xxxix. (1914) pp. 385-94 (5 pis). 

 t Proc. Linn. Soc. N.S.W., xxxix. (1914) pp. 152-6 (2 pis). 



