BY A. A. HAMILTON. 175 



acters varying considerably with the degree of moisture avail- 

 able. The succulent, cylindrical leaves of many Liliaceous 

 plants are almost identical, and are equally like the leaves of 

 some terrestrial orchids. Triglochin procera R.Br., when grow- 

 ing in mid-stream, and subject to a strong current, has flat leaves, 

 which are permanently bent, and lie on the surface of the water, 

 while the leaves of plants growing near the bank, or in the still 

 watei-s of a lagoon, are upright and almost terete. In the Orders 

 Juncacese, Restiacese, and Cyperacese, the leaves of many species 

 are so similar, that they afford very little assistance to the taxo- 

 nomist. The rigid, convolute, pungent-pointed leaves of Zoysia 

 fungensWiWd., are very similar to those of Sporoholus virginiciis 

 Kunth, when these plants are growing associated in a saline 

 estuary, both having adopted the same xerophytic, protective 

 agency against the natural forces operating against them, in 

 their exposed habitat. Schedonorus littoralis Beauv., has rigid, 

 pungent-pointed leaves, simulating those of a J uncus. 



Conclusion. 



A consideration of the varied influences brought to bear on 

 the modification of the morphology of leaves, as demonstrated 

 by the foregoing examples (which might be indefinitely multi- 

 plied), discloses, it is submitted, suilicient evidence to warrant 

 the assertion that the foliar characters in herbarium-specimens 

 should be cautiously advanced in the determination of a species. 

 It has been shown that a specimen taken from an individual 

 shrub may differ as much in its leaf-character from other ex- 

 amples taken from the same plant, or from a neighbouring shrub 

 of the same species, as it would from one taken from a distinct 

 species. The examples cited in this paper (p. 157) referring to the 

 inaccurate description of the position of the simple and trifoliate 

 leaves in Zieria involucrata, and the relative size of the leaves, 

 in Scosvola suaveolens and ^S'. microcarpa,{pAQ9) are instances 

 which show the necessity for extensive field-work, and the ex- 

 amination of a large quantity of botanical material in respect of 

 leaf-characters, before describing a species, or proposing a new 

 variety, the elasticity of the plant frequently showing disregard 



