Betts. — Autecology of Plants of Peridotiie Belt, Nelson. 



301 



The chlorencliyma consists of about 5 rows of large, roundish cells which 

 have thin walls and numerous chloroplasts. There are moderately large 

 air-spaces in this tissue. 



Then there comes a band of smaller, roundish cells which hate thickened, 

 lignified walls. Below this there is the phloem, which is a narrow band 

 of tissue. The xylem contains parenchymatous cells. 



35. Gahnia procera Forst. 



Habit. — This is a perennial tufted herb. The stems are about 2 ft. 

 high, and are stout. The leaves are as long as or slightly longer than the 

 stems, and are narrowed into long filiform points ; the margins are involute, 

 smooth above and scabrid below ; the sheaths are dark brown or almost 

 black. 



Anatomy. 



Leaf (figs. 29-32). — The transverse section of this is shown diagram- 

 matically in fig. 29. This shows that the leaf is involute and furrowed, and 

 that under each ridge there is a vascular bundle, accompanied by an 

 extensive development of sclerenchynia. The margin of the leaf is occu- 

 pied by a mass of sclerenchyma. Figs. 30-32 show the structure of the 

 leaf in more detail. 



Fig. 29. — Gahnia procera. Transverse section of leaf (x 36). 



b, sclerenchyma ; c, vascular bundles.. 

 Fig. 33. — Gahnia procera. Transverse section of stem ( X 24). 



b, vascular bundles. 



a, chlorenchyma ; 

 a, sclerenchyma ; 



The upper epidermis consists of small cells, which taper slightly towards 

 the outside of the leaf. The walls of these cells are thickened, especially 

 the external walls, which produce small papillae. There is no cuticle. 



The lower epidermis consists of very regular oval cells, which have their 

 cell-walls, especially the external ones, thickened. There is a thin cuticle 

 on the lower surface. 



