ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 913 



Bubus australis, and finds the external peculiarities of form connected 

 with modifications of anatomical structure. 



The stem of the species examined of Spartium, Casuarina, and 

 Ephedra, contains a strongly developed palisade-parenchyma in the 

 cortex, and a large number of stomata in the epidermis, the collen- 

 chyma being also replaced by sclerenchyma. In species with thick 

 stems, chlorenchyma is developed on both sides equally, and scleren- 

 chyma abundantly. Stems with few or no leaves exhibit more or less 

 the structure of leaves ; the species of Asparagus and CoUetia have 

 palisade-parenchyma in the cortex, and a large number of stomata. 

 The phyllodes of Acacia and the leaf-stalk of Mubus australis also 

 possess palisade-parenchyma. All the species examined have nume- 

 rous intercellular spaces in the cortical parenchyma. As the amount 

 of foliage decreases, the cortical parenchyma assumes more and more 

 the palisade form, and the coUenchyma becomes replaced by scleren- 

 chyma. When the collenchyma forms a closed ring, the number of 

 stomata in the cortex is small. The number of stomata also goes 

 along with the abundance of intercellular spaces and of brightly 

 coloured chlorophyll-grains in the parenchymatous cells. 



The palisade-form of the parenchyma the author considers pecu- 

 liarly favourable for access of light, diffusion of gases, and the rapid 

 transport of reserve food-materials — in other words, for assimilation. 

 The occurrence of sclerenchyma in the place of collenchyma he 

 explains on the ground of economy of space for the process of assimi- 

 lation. 



Finally, the author has determined that plants with few leaves 

 give out most oxygen, consequently assimilate most. The exclusion 

 of light caused the reserve starch to be stored up in the course of two 

 or three days, while in plants with abundant foliage this takes place 

 only in from eight to fourteen days. 



Structure of Climbing Plants.* — A close examination of a large 

 number of species convinced MM. Westermaier and Ambronn that, 

 notwithstanding the fact that they belong to so many widely separated 

 families, there are yet points of anatomical structure in which all 

 climbing plants are more or less distinguished from others. 



One noteworthy feature is the large size, at least in older stems, 

 of the vessels. In many instances these have a diameter of 200-300 /x, 

 and in some instances [Hyponthera guapeva and some passion-flowers) 

 they even exceed 0*5 mm. The essential constituent of the phloem, 

 the sieve-tubes, are in general remarkably well develoj)ed in climbing 

 plants. There is some difference in the development of the medullary 

 rays and the xylem. These differences in internal structui-e are no 

 doubt connected with the peculiarities of their external morphology, 

 and with the physiological peculiarities connected with their power of 

 climbing. 



Monotropa Hypopitys.j — Dr. F. Kamienski has reinvestigated 

 the structure of the vegetative organs of this plant, in order to deter- 

 mine the vexed question of the mode in which it obtains its nutriment. 



* Flora, Ixiv. (18S1) pp. 417-30. f Bot. Ztg., xxxix, (ISSl) pp. 457-Gl. 

 Ser. 2.— Vol. I. 3 P 



