BiED. — Lianes of the Ancient Forest of Canterbury Plains. 331 



at ends of minute arrested branches, base cordate or truncate, slightly 

 coriaceous, glabrous, margin entire. Petioles 3-5 mm., rounded at base, 

 towards the lamina grooved dorsally, puberulous. Stipules membranous, 

 closely pressed to stem, deciduous. 



(ii.) Leaf -anatomy. 



{a.) Shade Leaf. — Epidermis : Cells of upper epidermis large ; walls 

 slightly thickened, outer walls convex ; lower epidermal cells smaller and 

 outer walls straighter ; stomata on lower surface only. Chlorenchyma : 

 Palisade and spongy tissues not sharply difierentiated ; two upmost layers 

 of cells isodiametrical and loosely packed ; beneath these, 3-4 layers of cells 

 loosely packed and with large intercellular spaces. Leaf-margin : Cells 

 larger ; walls more convex and more thickened. Bundle-sheath poorly 

 developed. Calcium oxalate in aggregate crystals. 



(6.) Sun Leaf. — Epidermis : Cell-walls thicker ; anthocyan often in both 

 upper and lower epidermis. Chlorenchyma: Palisade — 2 layers cells 

 slightly elongated, and more closely packed. Spongy — Intercellular spaces 

 smaller. 



6. Parsonsia heterophylla. 



a. life-form. 



Although not so abundant as Muehlenheckia australis, this species is quite 

 as widely distributed. It is present in its largest numbers on trees and shrubs 

 at the forest-margin. The stems, covered with a rough greyish bark and 

 slightly swollen at the nodes, are at most 3-4 cm. in diameter. They reach to 

 a height of fully 20 m., and before doing so may trail along the forest-fioor 

 for 12 m. or more, adventitious roots often arising from the trailing portions. 

 The stems of plants in the forest-interior hang from the supports in a manner 

 similar to those of Muehlenheckia australis, and, like these, they are often 

 twisted and encircle portions of some former support, which has been 

 strangled. The stems differ in behaviour from those of M. australis in that 

 the twining of Parsonsia is always sinistrorse. They are thus of less efficiency 

 in gaining support, but they possess a marked superiority in that they can 

 twine round much thicker supports, the climbing-stems often being found 

 coiled round tree-trunks itp to 25 cm. in diameter. The stems show a marked 

 tendency to twine round each other, in many cases lateral shoots inter- 

 twining with the primary. By this mutual support they have a better 

 chance of reaching higher positions. In bright light the stems bear leafy 

 branches, which form a dense covering on the support. The stems may 

 stand erect, but more commonly they lie horizontally on the top of the 

 support. Others project from the latter, and gradually bend down until 

 they hang almost vertically. The stems then commence to twine back 

 round themselves, and should they reach any one of the many shoots which 

 arise from these hanging stems — shoots which at first stand erect and then 

 stretch outwards — the primary shoots may twine round one of these, and 

 the two together thus reach some new support. In such positions on a 

 support the tendency of stems to intertwine is very marked, and " ropes " 

 of as many as 8 stems often project from the support for fully 2 m. These 

 " ropes " are the chief means by which distant supports are reached, for, 

 although adventitious shoots arise from various parts of adult plants, they 

 are not numerous, and, unlike those of Muehlenheckia australis, never 

 attain a great length, while their growth is very slow. 



