136 Transact tons. 



Art. XVIII. — Notes on the Autecology of certain Plants of the Peridotite 

 Belt, Nelson : Part I — Structure of some of the Plants (No. 2).* 



By M. Winifred Betts, M.Sc, 



Communicated by Professor Benham, F.K.S. 



[Read before ike Otayu Institute, 10th December, 1918 ; received by Editor, 30ih 

 December, 1918 ; issued separately, 26th May, 1919.] 



10. Rubus australis Forst. 



Growth form. — " A tall climber, reaching the tops of the highest trees ; 

 stems stout, woody at the base ; branches slender, drooping, armed with 

 scattered recurved prickles. Leaves 3-5-foliolate or rarely pinnate, with 

 2 pairs of leaflets and a terminal one ; leaflets coriaceous, glabrous, very 

 variable in size and shape, 2-5 in. long, ovate-oblong or ovate-lanceolate 

 to linear-oblong or almost linear, acute or acuminate, truncate or cordate 

 at the base, sharply serrate ; petioles and midribs armed with recurved 

 prickles, "f 



Anatomy. 



Leaf. — -The upper epidermis consists of small cells, which are oval or 

 rectangular in transverse section. These cells have their walls somewhat 

 thickened, and there is a thick smooth cuticle. There are no stomates 

 on the upper surface. 



The lower epidermis is formed of small more or less squarish cells. 

 These cells have their walls slightly thickened, and there is a cuticle, which 

 is not, however, as thick as on the upper face of the leaf. Stomates are 

 frequent on the lower surface. The guard-cells are small, and are at the 

 same level as the epidermal cells ; the stomates are protected by guard- 

 cell ridges. 



Beneath the upper epidermis there is a hypoderma consisting of large 

 rectangular cells with thickened walls. 



The chlorenchyma is dift'erentiated. The palisade tissue is composed 

 of 3 layers of thin-walled cells containing fairly large chloroplasts. The 

 2 outer layers are very compact, but there are air-spaces between the 

 cells of the inner layer. The spongy tissue consists of rather small, 

 irregular, thin-walled cells, which are loosely arranged. 



The midrib is prominent. Above the xylem there is a group of large 

 cells with thickened lignified walls. The xylem contains vessels of large 

 diameter. Beneath the phloem there is a zone of sclerenchynia, in which 

 the cells are small and have thick walls and small cell-cavities. Below 

 this zone there are some large cells with thickened lignified walls. Above 

 the midrib the epidermal cells are much smaller, and a few of them are 

 produced into unicellular hairs, with thick walls which are not cutinized. 

 Above and below the midrib there is colleuchyma. 



Stem. — The epidermis consists of very small dome-shaped cells with 

 their lateral and their external walls cutinized. The cuticle is uneven, 

 and is very thick. 



* For No. 1 SCO Trans. N.Z. Inst., vol. 50, pp. 230-i:i 1918. 



tT. F. Cheeseman, Manual of the New Zealand Flora, 19U0. (See No. 1 of these 

 Notes, loc. cit., p. 231.) 



