546 Transactions. 



The body of the paper consists of two parts : (1.) A general descrip- 

 tion of life-forms, and of variations of each species according to station. 

 (2.) A short anatomical account of certain of the more characteristic plants of 

 each formation. Attention also will be given to such general conclusions as 

 may be drawn from observations of the plants and their habitats, and 

 some comparison made between these and the results given by authorities 

 on the subject. 



Methods of Observation. 



The methods employed may be divided, roughly, into two classes — 

 (1) Field-work ; (2) laboratory-work. Unfortunately, almost the whole of 

 the field-work had to be done during the winter months — a serious drawback, 

 more especially in the case of annuals. It is for this reason, most of all, 

 that no mention has been made of the flowers of the difierent species, ex- 

 cept in a few cases of flowering out of their usual season. 



To supplement the field-work, plants of several of the species observed 

 were planted, some in the open flower-beds, others in the greenhouse at 

 Canterbury College, and these have been examined from time to time, and 

 compared with specimens from their natural habitats. 



Districts observed, and Plant Formations. 



The Heathcote, on the banks of which most of the field-work has been 

 done, is a small, sluggish stream that forms with the River Avon an estuary, 

 invaded by every high tide, and left a barren expanse of mud at its ebb. 

 Both streams are for a considerable distance affected by the tides, and so 

 their banks and the immediate surroundings of the estuary are favourable 

 situations for halophytic plants. Nowhere do they flourish better than in 

 the little patch of ground in the last bend of the Heathcote, and in this 

 comparatively small area there exist at least three different plant forma- 

 tions : (1) Salt-marsh formation ; (2) salt-meadow formation ; (3) brackish- 

 water formation. 



Of the first of these, the salt marsh, it is difficult to say which is the 

 dominant species. Probably it would be better to say that there are really 

 two dominant species, Leptocarpus simplex and Juncus maritimus. Looking 

 over the expanse of rushes in the winter, one sees alternately dark and 

 lighter patches, the former being composed of L. simplex, the latter of 

 J. maritinms. The monotony of these acres of rushes is broken only by 

 purplish-grey clumps and lines of Plagiapthus divnricatus. These three 

 species, then, are the sole occupants of the greater part of the salt marsh ; 

 but at its extreme edge there are a few of the typical species of the salt 

 meadow. These plants must have been excluded from the salt marsh 

 through their inabiUty to cope with the rushes, and not through any un- 

 suitability of edaphic conditions, for the few found there are particularly 

 luxuriant. 



In the salt meadow the vegetation is more varied, and is composed of a 

 turf of close-gromng plants with creeping stems. The mats of Salicornia 

 australis and SeUiera radicans form the most noteworthy feature of this 

 formation. 



Again, the salt meadows are traversed by channels, evidently dug for 

 drainage purposes, and these, at high tide, are filled with water. Here 

 Plagianthus divaricatus is the dominant species, though all the plants of the 

 salt meadow, with the exception of Atriplex patula, and the addition of 

 Samolus repens, root in the sides of the channels, or even in the very bottom. 



