BiBD. — Lianes of the Ancient Forest of Canterbury Plains. 329 



part of the main one, and thus finally may reach a height of 2 m. or more. 

 At other times they project from the liane almost horizontally, and in many 

 places finally rest on plants which are 2-3 m. distant. They thus illiistrate 

 the suitability of the term " searcher shoot," which is applied by Goebel 

 to such organs (1905, pp. 453-54), for, in obtaining new supports for the 

 liane, they are of immense importance. During the first metre of their 

 growth they exhibit no nutation or torsion, but after attaining this length 

 the shoot, even in the absence of a support, slowly commences sinistrorse 

 spiral growth. If it comes into contact with a support the position of the 

 latter determines the direction of the twining — i.e., it may be sinistrorse 

 or dextrorse. 



A. LEAF. 



(i.) Leaf-form. 



Leaves alternate, petiolate, 4-5-6*5 cm. long ; ovate, apiculate, cordate 

 or truncate at base ; membranous or subcoriaceous ; glabrous, entire, 

 margin undulate. Petioles 1-1-5 cm. long, bent in varying manner, so that 

 the lamina usually lies facing the light. Dorsal groove along entire length. 

 Stipules membranous, closely pressed to stem, deciduous. Shade leaves 

 difier but slightly from sun leaves ; they are slightly larger and more 

 membranous, while the petioles are a little longer. 



The above description applies to an ordinary adult leaf, but on an adult 

 two other distinct types of leaves occur — viz., (a) reniform, (6) trilobed 

 with acuminate apex — which arise in a definite order. The first leaf to 

 appear on a lateral shoot is small and reniform. Either at the next node 

 or two or three nodes distant there is borne a leaf which approaches more 

 or less closely to the 3-lobed acuminate type, this being succeeded by the 

 usual adult type. The same sequence is apparent in developing seedlings, 

 and there the three types, which are very distinct, are connected by inter- 

 mediate forms. The series, however, is sometimes broken by the omission 

 of any stage except the first. Succeeding the reniform leaf is one in which 

 the indentation at the leaf-tip is slightly reduced, and two small incisions 

 are present, one on each side of the tip. These incisions in later forms 

 become more and more marked, and at the same time the leaf-tip becomes 

 at first flat, and then produced into an acuminate apex. At this stage 

 the leaf belongs to the 3-lobed type. In leaves succeeding this the incisions 

 become smaller, and disappear in the final type, which has an entire undulate 

 margin. 



(ii.) Leaf-anatomy. 



(a.) Shade Leaf (Juvenile). — Epidermis : Upper epidermis consists of 

 large ovoid cells with thin walls ; lower epidermis, smaller cells ; stomata, 

 lower surface only, slightly raised. Chlorenchyma : Palisade is poorly de- 

 veloped ; cells in uppermost layer of mesophyll are almost isodiametrical, 

 and are loosely packed ; a collecting layer beneath this connects with a 

 spongy tissue of about 3 layers of spherical cells loosely arranged ; these 

 cells difier from the palisade in their tendency to elongate parallel with 

 the leaf-surface, and in their containing few chloroplasts. Leaf-margin : 

 Outer walls of epidermal cells very convex and thickened ; chlorenchmatous 

 cells almost spherical. Vascular bundle poorly developed ; no distinct 

 sheath. Calcium oxalate : A few aggregate crystals. 



(b.) Sun Leaf (Adult). — Epidermis : Striated cuticle ; lateral walls also 

 thickened. Stomata level with epidermal surface. Hypoderm : Above and 



