32 Transactions. 



(c.) Root. — Much as in R. subsericea. 



(d.) Flower and Fruit. — Capitula 3 mm. long and about 1-5 mm. wide. 

 Involucral bracts in three to four series. Florets from fifteen to twenty, 

 the peripheral females the most numerous. Cypsela oblong, puberulous ; 

 pappus-hairs copious and slender. 



(y.) EPHARMONIC VARIATIONS. 



No epharmonic variations were observed in the Cass Valley, save that 

 some mats had shorter branchlets closer together than others. Greenhouse 

 cultures of six months" growth demonstrated a peculiar fact. The leaves 

 on the ordinary branchlet are decidedly distichous as far as appearance 

 goes, but the spring growths in the moist greenhouse produced branch- 

 lets with an alternate phyllotaxy. The writer was unable to obtain young 

 plants or to make seeds germinate, but it is likely that the juvenile form 

 has alternate leaves. This assumption is based on an analogy with the 

 seedling forms of R. tenuicaidis, which have the same appearance as some 

 of the new growth in older mats when these for some reason or other form 

 a luxurious growth. 



(8.) Conclusions. 



This species is rather a remarkable one, and although growing on old 

 terrace it has so many xerophytic characters that it is probable that its 

 habitat is of comparatively recent adoption. Its small densely hairy leaves 

 are compacted into two opposite rows on the branchlets, thus giving as 

 compact a branchlet as in the rosette-forms like R. lutescens ; its upper 

 stomata are covered by the tomentum, and the lower ones are sunken ; its 

 stems are strongly lignified, the pericycle-cylinder adding to the rigidity, 

 though this stem-solidification may be an adaptation to the " burrowing " 

 habit of the stem in the old terrace. 



On the other hand, its reversion in a moist culture to an alternate leaf- 

 arrangement like the other raoulias seems to point to a primitive mesophytic 

 habit. The seedling forms of R. tenuicaulis and R. australis have a much 

 more mesophytic appearance than the adult, and possibly the seedling 

 form of R. Monroi shows similar features. 



Again, R. Monroi, by its " scattered " mat, intermingled with other- 

 plants, illustrates the transition from the mat-form to that growth-form 

 where an underground stem sends up tufts of leaves at intervals. 



Now, this plant is much more compacted in drier situations, and in 

 some places in the Lower Waimakariri Valley the writer has observed it 

 forming a comparatively close mat. In the Cass Valley it appears to be 

 adopting a mesophytic habitat and growth-form. It has been suggested 

 above that its seedling form is probably of mesophytic structure. Does 

 this bear out Cockayne's theory (1910, p. 62) that the ontogeny of some 

 of the indigenous plants affords a clue to the former climate of New Zealand ? 



(H.) Scleranthus biflorus var.* 

 (a.) Habitat. 



Scleranthus biflorus is found chiefly on old terrace, and to a less extent 

 on grade 3. It is totally absent from grade 1, and occurs occasionally on 

 grade 2 where this merges into grade 3. 



* This variety of the species is not the type, since it is only one-flowered and of 

 somewhat different growth-form. 



