474 ECOLOGICAL STUDY OF SALTMARSH VEGETATION. 



The Sea-blite, Suaeda maritima, a cosmopolitan species and a 

 member of the same family as the Salicornia, (Chenopodiaceae)J 

 is usually associated with the latter either as a competitor — in 

 the tidal zone — or as a colleague in the work of clothing the 

 intermediate barren plain. In the tide-flooded area, the some- 

 what woody stem of the Seablite is early decumbent and re- 

 clines on the soft mud, producing an abundance of lateral ad- 

 ventitious roots which spread horizontally on the surface of the 

 slimy ooze (Plate xxvii., fig. 22) . The extremity of the stem 

 is curved upwards and plentifully furnished with divaricate 

 branches thickly clothed with succulent, semi-terete leaves. The 

 ramification of the interlaced branches with their heavy canopy 

 of foliage, in combination with the close network of surface- 

 spreading, matted roots, constitutes its defensive system. In 

 the numerous conflicts in which the Seablite and the Salicornia 

 are engaged, the latter generally emerges victorious, its vegeta- 

 tive reproductive system and perennial growth enabling it to 

 overcome its shorter-lived opponent, which is entirely dependent 

 upon sexual reproduction for colonisation. Seedlings of the 

 Salicornia attempting to obtain a footing in the Seablite forma- 

 tion are promptly suppressed by their taller antagonist, which 

 de2)rives them of the necessary light by interposing its leafv 

 curtain, and prevents their lateral growth by the density of its 

 own superficial root system. Invasion of the Salicornia by the 

 Seablite is equally futile, seedlings of the latter obtaining a tem- 

 porary footing in the Salicornia carpet finding it too compact to 

 penetrate, the inability of the adventitious roots to reach the 

 surface of the marsh resulting in the collapse of the intruders. 

 The frequent breaches in the Salicornia carpet, due to unfavour- 

 able conditions arising in the habitat, afford the Seablite numer- 

 ous opportunities for encroachment. Its quickly germinating 

 seeds, of which lai'ge quantities are shed in contiguity to the 

 Salicornia, are swept by the wash of the tide into the denuded 

 gap, which is invested with a sturdy growth of the Seablite 

 before its slower moving antagonist is able to enter the breach. 

 When the latter arrives at the margin of the Seablite formation, 

 its wiry rhizomes are insinuated under the shallower root system 

 of its opponent, and, as the shorter-lived Seablite disintegrates, 

 the rhizomes of the Salicornia, rising obliquely, occupy the 

 ground before a new crop of Seablite seedlings can secure a 

 footing. The invasion continues until the Seablite is either 



