Vol. X 5 No, 2.] Leaf Structure of Zoysia pun gene, Willd. M 



[N.S.] 



epidermis and thus form the strengthening agency at the 

 periphery of the rolled-up leaf. Such is the nature of the 

 adaptation for withstanding and warding off the injurious 

 effects of storms and winds. 



Chlorophyll-containing tissue.— This tissue is composed of 

 a mass of closely packed, irregularly shaped, cells with very 

 little intercellular spaces. By this reduction in the size of the 

 intercellular spaces, the transpiring surface becomes smaller and . 

 as a necessary consequence, transpiration itself is reduced. 

 These cells lie between the vascular bundles, and the layers 

 of motor cells in most cases forming nearly a ring round 

 the former. This position is obviously of distinct advantage 

 and, in addition to storing the water-supply brought up by the 

 vascular bundles, serves to protect them from th? intense glare 

 of the sun. The chlorophyll tissue is also restricted in amount 

 and the corpuscles are few in number. This accounts for the 

 extreme scarcity of starch grains in the leaves. 



To sum up, the leaf-structure of Zoysia pungens is 

 remarkably modified to suit the surrounding environment and 

 the main directions in which the adaptations have occurred 

 are, the economic utilization of a very limited water-supply, 

 the prevention of excessive transpiration, the withstanding of 

 mechanical strain due to winds, and lastly the shutting off of 

 rhe intense glare of the sun. 



EXPLANATION OF PLATED 



Plate V. 



A. Part of Plant (Natural size). 



B. Do. showing growing tip (Nat. size) 



C. A leaf and leaf-sheath x 4. 



Plate VI. 



(The leaves were fixed in Absolute Alcohol and sections 



cut by hand). 



D. Transverse section of the leaf x about 100 diam. 



(The crossed lines represent stereome, the circles with 



dots vascular bundles, and cones with horizontal and 

 lateral lines, Motor cells.) 



E. Transverse section of the leaf x about 300 diam. 



(Ep 1 , Lower Epidermis; 



Ep\ , Upper Epidermis ; 



St., stomata; Ster., stereome. 



C, Chlorophyll-containing tissue. 



V. B., vascular bundles; I.S., inner sheath ; 



O. S., outer-sheath; M. C. Motor cells.) 



