338 Transactions. 



wind and become tangled in the branches of an adjacent tree. Kecom- 

 mencing its upward growth on this new support, the liane may ultimately 

 reach its greatest height. In places where shrubs form the only available 

 support, the liane may bridge the spaces between the shrubs, and continue 

 its growth along the tops of the shrubs for a distance of 20 m. or more. 

 As a rule, the liane forms no coiled masses at the base of a support, and 

 it seems probable that this is due to the efficiency of the tendril as a 

 climbing-organ. And that the tendril is not an ephemeral structure is 

 shown by its persistence on stems which have attained a thickness of 6 cm. 

 Adventitious shoots are conspicuous on adult shoots in the shade. They 

 may arise singly or in groups of 2 or 3, and, though very slight, can rise 

 erect for about 60 cm. The first leaves are very small, being at most 

 4 cm. long and 2-3 cm. broad, but the size of succeeding leaves gradually 

 increases. However, on the distal portion of the stem the leaves for 

 a long time remain quite small, thus facilitating free movement of the 

 tendrils. The tendrils arise early on the shoots, often being present on 

 the second node, and thu.s these adventitious shoots are of great value 

 to the plant in gaining new supports. 



B. LEAP. 



(i.) Leaf -form. 



Leaves alternate, petiolate, 5-9 cm. long, oblong-lanceolate or ovate- 

 lanceolate, acuminate, coriaceous; upper surface very dark green and 

 glossy, lower surface lighter green, margin entire. Petiole 0-5-1 cm., 

 dorsal groove, often twisted. Shade leaves are larger than sun leaves 

 (sometimes 12-13 cm. long), more membranous, and with longer petioles 

 (1-5-2 cm.). 



(ii.) Leaf -anatomy . 



(a.) Shade Leaf. — Epidermis : Slight cuticle ; lateral walls also thick : 

 stomata, lower surface only, slightly elevated. Chlorenchyma : Choro- 

 plasts large, spherical. Palisade — 3 layers; cells almost as broad as 

 long ; not very tightly packed ; tissue occupies slightly less than half the 

 cell-thickness. Spongy — 5-7 layers ; majority of cells more or less oblong, 

 with long side parallel to leaf-surface. Leaf-margin : Towards the margin 

 the cells of palisade and spongy tissues become more and more alike, and 

 form a homogeneous tissue which near the margin itself is composed of 

 oblong cells resembling those of the spongy tissue, but with smaller inter- 

 cellular spaces, and containing very few chloroplasts. Vascular bundle : 

 Surrounded by a parenchymatous sheath. Calcium oxalate : Present in 

 aggregate crystals. 



(6.) /S';m ief//. — Epidermis : Cuticle thicker; stomata not raised. 

 Chlorenchyma : Palisade — -Cells more elongated and more closely packed : 

 tissue occupies fully half the leaf-thickness. Spongy — Intercellular spaces 

 smaller. Leaf - margin : Hypoderm 3^ layers ; cells of chlorenchyma 

 spherical. 



(c.) Climbing -organ. — (i.) Form and Behaviour: The tendrils arise singly 

 in the axils of leaves, and it is probable that, like those of other members of 

 the Passifloraceae, they are modified inflorescence branches. Lateral shoots 

 of the plant arise from buds situated in the axils of the tendrUs. The tendrils 

 at first project beyond the growing apex of the stem, and then bend out- 

 wards and downwards, at the same time increasing in size until finally 



