36 Transactions. 



and in greater quantities near the edge of the terrace bordering on the 

 liver-bed, where it forms thick mats, curving over the terrace-edge, and 

 forming a rounded " beading " often several metres long. 



(8.) Life-form. 



(1.) General. — The growth-form of adult plants is a dense, widely spread- 

 ing flat mat. Occasionally the growth is so close as not to allow the 

 establishment of other plants among it, but usually the creeping branches 

 are matted in amongst a great variety of other plants. The contour is 

 usually smooth, but the surface is very rough, being formed by the tips 

 of the small coriaceous acute leaves, arranged more or less vertically. In 

 late autumn numerous drupes, port-wine-coloured, or of various shades 

 of translucent greenish-blue,* are very conspicuous, as they lie in vast 

 quantities half- buried in the mat. 



This plant, having a woody creeping stem, and short woody branchlets 

 which project above the surface of the soil, cannot be said to have 

 filling-material any more than has Raoulia Monroi. 



(2.) Coloration. — The usual colour of the leaves is a dark green. During 

 the winter, however, the upper surface, the margins, the lower midrib, 

 and parts of the. lower surface assume a dark-brownish tint, due to the 

 formation of anthocyan in the subepidermal cells. The pigmented sap 

 does not occur in the epidermal cells, but in certain cells and areas of cells 

 in the outer layer of mesophyll, chiefly in the palisade. 



(3.) Morphology. — (a.) Stem. — The main stems are woody, brittle, 

 yellowish, and stout, being often as much as 0-5 cm. in diameter. They 

 are horizontal, subterranean, root copiously, and give off secondary branches 

 which end in branchlets as in the raoulias. 



The branchlets- vary in length from 0-5 cm. to 2 cm., and the axis 

 averages 1 mm. in diameter. Towards their distal ends they are crowned 

 with a small tuft of spreading leaves, arranged m opposite pairs on the axis. 



The young stem shows the following anatomical structure : — Epidermis : 

 Small oval cells ; cuticle thin, wrinkled, yellowish. Cortex : Cells thin- 

 walled, spheroidal, loosely packed ; certain of the cells in the outer layers 

 contain anthocyan- — this causes the spots and streaks of red or purple on 

 the young stem. There is a distinct large-celled endodermis. Stele : 

 Phloem rather wide ; four or five xylem masses. Pith : Polygonal cells 

 containing much starch. 



The anatomy of a mature stem is as follows : Secondary growth soon 

 commences. Secondary xylem quickly forms a complete ring. The pith 

 also soon becomes lignified. A cork-cambium forms in the inner layers of 

 the cortex, and soon the tissues exterior to this are shed. The vessels of 

 the secondary wood have very large lumina. The walls of the lignified 

 pith in old stems are very thick and pitted. 



(b.) Leaf. — The leaves are borne in opposite pairs on the branchlets. 

 A peculiar feature, characteristic of the whole genus, is the form of the 

 stipules, which are united at the sides of the node between the bases of the 

 pairs of leaves, and are hence interpetiolar in position. The leaves are 

 from 4 mm. to 7 mm. long, oblong-lanceolate, gradually narrowed into 

 a short petiole, and with an acute apex ; they are distinctly thick and 

 coriaceous, with obscure venation. Both surfaces, but chiefly the upper, are 



* There are apparent!}' two well-marked varieties. 



