247 



ON THE LEAF-ANATOMY OF SC.EVOLA CRASSIFOLIA, 

 AVITH SPECIAL REFERENCE TO THE EPIDERMAL 

 8ECRETI0N. 



By Mahjokie Isabel Collins, B.Sc, (•Syd.), Demonstkatok in 

 Botany, the Uniyeksity of Adelaide. 



(Plates xxvii.-xxviii., and six Text-figures.) 



Introduction. 



Sccevola crassifolia forms a prominent element in the sand-dune 

 Hora near Adelaide, where it occurs in association with Sjnnifex 

 hirsutus, with such shrubs as Olearia axillaris, Leucopogon 

 Richei, etc., and with smaller plants such as Pelargonium aua- 

 trale, Lotus australis, (Eiiothera 6^e7^n^s (introduced), and Senecio 

 lautus (3, p. 584). 



In habit, .S'. crassifolia is a low, spreading shrub, which is 

 able, by lateral growth, to occupy large areas of the dune. Its 

 older woody stems form a dense undergrowth, in which a quantity 

 of blown sand and dried leaves of Posidonia are accumulated, 

 thus helping to build up the dunes. 6'. crassi/olia is able to 

 survive burial in sand by an upward elongation of the stem, and 

 by the development of adventitious roots. 



Owing to the extreme stickiness of the buds and young leaves, 

 the varnishing or lacquering of the surface of older leaves, the 

 dullness of surface, and the succulence of mature leaves, it was 

 thought that an examination of the leaf-anatomy would prove 

 interesting. The investigation was carried out in the Botanical 

 Laboratory of the University of Adelaide, at the suggestion of 

 Professor Osborn, to whom I am much indebted for his constant 

 help and encouragement. 



Summary of Previous Investigations. 



Despite its particular interest, the N.O. Goodeniacea^ has 

 received but scant attention at the hands of botanists. As early 



