Betts. — Ai(feroI'j(/i/ of I'lants of Peridotite Belt, Kelson. 147 



18. Anisotome filifolium (Hook, f.) Cockayne and Laing. 



Growth-form. — This is a slender aromatic herb. The stems are about 

 4-8 in. high, smooth and striate. The leaves are 3-6 in. long, and are 

 flaccid ; the blades are very variable in size, and are ternately divided into 

 narrow filiform acute segments |— H in. long. The petioles are long, slender, 

 sheathing at the base ; the sheaths are short, broad, and membranous. 



Anatomy. 



Leaf (fig. 11). — The epidermal cells are large, those of the upper 

 epidermis being a little larger than those of the lower ; the cell-walls are 

 thickened, the external walls being very much thicker than the lateral or 

 internal ones. There is a cuticle on both surfaces. Stomates are found on 

 both surfaces, being somewhat more numerous on the lower than on the 

 upper face. The stomates are raised above the epidermal cells, but not 

 above their thickened walls. The guard-cells have thickened walls, and 

 the stoma is protected by guard-cell ridges. 



Pig. 11. — Anisotome filifolium. Transverse sections of leaf (x 175). a, cuticle; 



6, thickened epidermal walls : c, stoma ; d, oil-duct ; /, xylem ; g, phloem ; 



/;, spongy tissue. 

 P'iG. 12. — Anisotome filifolium. Transverse section of jieduncle (diagrammatic) ( X 17.5). 



a, sclerenchyma ; b, cortex ; c, pericycle fibres ; d, xylem ; e, lignified 



pith ; /, pith-cavity. 



The chlorenchyma is differentiated into palisade and spongy tissue. 

 The palisade tissue is composed of 1-4 rows of cells (1 near the margin, 

 4 in the centre of the lamina). The cells are large and elongated, thin- 

 walled and compactly arranged, and contain abundant chloroplasts. The 

 palisadic tissue passes gradually into the spongy, which consists of rather 

 irregular cells with thin walls and containing abundant chloroplasts. This 

 tissue is loosely arranged, so that there are large air-spaces. There are 

 large air-spaces beneath the stomates. Above the lower epidermis there is 

 a layer of chlorenchymatous cells, which are smaller, more regular, and are 

 closelv arranged. 



