468 ECOLOGICAL STUDY OF SALTMARSH VEGETATION. 



coloured flowers is complementary to the absence of insects. The 

 rarity of coloured fruits is also notable. 



• A feature of the colour scheme in the marsh remarked by 

 numerous writers is the occurrence of chromatism in the stems 

 or leaves of certain plants, more particularly Salicomia. The 

 red colouration is general^ attributed to the presence of antlio- 

 cyanin, and various hypotheses have been advanced in explanation 

 of the phenomenon, e.g. environmental — extreme salinity (3, p. 

 337), a dry station (4, p. 350) ; phenological— red in autumn 

 (39, vol. 16, p. 189), red in winter (24); heredity — transmission 

 from parent to offspring (22, vol. 8, p. 102). Tufts of Sali- 

 comia were noted by the writer bearing both red and green 

 stems in all stations in the marsh and at all seasons of the year. 

 The percentage of red stems was lowest in summer and reached 

 the maximum at midwinter. In June the marsh plain at Honie- 

 bush Bay had acquired a purplish tint owing to the prevalence 

 of coloured stems of the Salicomia. The Sea-blite, which was 

 also affected, showed a slight increase only in the proportion of 

 coloured herbage during the winter season. Other plants in 

 the local marshes which have developed chromatism are — Sjier- 

 gularia rubra, Atriplex patula L., Mesembryanthemum aequi— 

 laterale Haw., Polycarpon tetraphyllum Loefl., Bottbellia com- 

 pressa L. f., Haloragis micrantha R- Br., Eumex acetosella L. 

 The latter is noted as " Often turning red."* 



Taxonomic. 



In systematic botany the floral structure is important, but in 

 ecology the growth form is the consequential character. The 

 role of ecology in systematic botany has been considered by 

 various writers, and numerous instances of species and varieties 

 whose morphology has been affected by the formative factors 

 dominating their environment have been recorded. Of Atriplex 

 patula, Miss Cross (7, p. 550) says, " ! In the dried parts of the 

 meadow the leaves are smaller and very rarely hastate; some- 

 times they are almost sessile. In the marshes the leaves reach 

 their greatest size, and have the typical hastate shape . " 



The extremely diverse factors operating in contiguous stations 

 in the marsh have left their impress on this exceptionally plastic 

 species, which is well represented locally. Its behaviour in our 

 marshes is similar to that noted by Miss Cross, the leaves rang- 

 ing from narrow ovate to rhombic and hastate, in the passage of 



*F1. Austr., v., p. 265. 



