570 Transactions. 



These were planted, on the 1st April, and their leaves examined anatomically 

 towards the end of September. Of those in the open flower-beds, none 

 flourished except Cotula coronopifolia ; but all those planted in the green- 

 house with the exception of Salicornia grew splendidly. They were plenti- 

 fully watered with fresh water, but the greenhouse was not artificially heated 

 in any way. 



They were found to differ in general appearance from plants from their 

 natural habitat in the following points : (1) They were less compact and 

 less stunted in habit ; (2) their leaves were much thinner ; (3) their leaves 

 had a brighter green colour. 



1. Salicornia australis. 



This appeared to die at once, not one httle green shoot remaining ; but 

 it was watered with the rest, and early in October tiny green shoots ap- 

 peared on the dry stems. 



2. Spergularia media. 



The plants lost their cushion-like habit, and developed long, straggling 

 branches, with longer and more flattened leaves. On an average, the 

 leaves were four-fifths of the thickness of those from the meadows. 



Anatomical Difjerences in Leaf. — There was no decrease in the number of 

 layers, though all the cells of the mesophyll were somewhat smaller. The 

 chlorophyll grains were not more numerous, but were larger. The cuticle 

 had no markings on its surface, and this was no doubt due to the fact that 

 the plants were not exposed to such strong insolation. 



3. Apium prostratum. 



This species gxew very \dgorously, and on comparing the leaves, first 

 with some which had been in spirit since the 1st April, and then with leaves 

 of plants which were at about the same stage in the natural habit, it was 

 found that their thickness was, on an average, only half that of the other 

 two. Sections being examined, it appeared that this decrease in thickness 

 was due not to a lessened number of layers, but to a diminution in the size 

 of the cells of the palisadic tissue. In all cases the depth of the two layers 

 was less than one-third of that of the corresponding layers in those which 

 had grown in the channels. The spongy parenchyma was as weU developed 

 in one case as in the other. 



The midrib showed no decrease in size corresponding to the diminished 

 thickness of the whole leaf. 



4. Samolus repens. 



(1.) Leaves of Plants groivn in the Greenhouse. — These on an average were 

 but half the thickness of those from the natural habitat. This was due 

 both to reduction in the number of palisadic layers, only three being found, 

 and to a rediction also in their size. There did not appear to be any 

 increase in the number of chlorophyll grains. 



(2.) Leaf of var. stricta (fig. 14, a). — This showed the follomng differ- 

 ences from that of the ordinary variety from the salt marsh, though it was 

 of the same thickness : — 



Epidermis : The outer walls were not so thick or so distinctly cuticu- 

 larised, and the deposit of wax was less. 



