Bird. — Lianes of the Ancient Forest of Canterbury Plains. 337 



(ii.) Leaf-petiole: Anatomy (see fig. 7). — Before the petiole attains a 

 length of 1-5 cm. it is devoid of stereome. Four vascidar bundles are at 

 this stage well developed, and the rigidity of the petiole is further increased 

 by abundant collenchyma. Stereome first appears between the bundles 

 in a narrow ring, which gradually increases in thickness, and which, ex- 

 tending outwards, joins more masses of stereome which meanwhile have 



Fig. 7. — Clematis indivisa. Diagrams of tendril, showing development of stereome. 

 ep., epidermis ; st., stereome ; vase, bmid., vascular bundle. 



developed outside the phloem. At the same time the stereome develops 

 more and more towards the centre of the petiole, until finally all the 

 ground - tissue except the 5 or 6 rows adjoining the epidermis becomes 

 lignified. 



These outer cells contain chlorophyll, while in a few cells anthocyan 

 may be present. The epidermis has a thick cuticle. Stomata are sunk 

 below the surface. 



9. Tetrapathaea australis. 



A. LIFE-FORM. 



Although the species is found chiefly at the edge of the forest, many 

 plants grow in the inner portions and even reach the summit of the tallest 

 trees. The stem of the liane, growing up to 12 cm. in diameter, usually 

 ascends close to the trunk of its support, but it sometimes trails for 10 m. 

 along the ground before gaining the support. It is evident that a tree-trunk 

 is a poor support for a tendril-climber, but the presence of decaying stems 

 of species of Ruhus at the bases of trees indicates a means by which 

 Tetrapathaea may have reached the lofty branches. The liane produces 

 practically no branches in the shade, but on the exterior of the supporting 

 tree it bends over, and ultimately gives ofi numerous branches, the foliage 

 of which is often so thick as to obscure from view the supporting tree 

 (Plate XXIV, fig. 1). Continuing their growth, these branches hang down, 

 and the weight of the masses is frequently sufficient to break the branches of 

 the support. The long rope-like stems may then be swung to and fro by the 



