BY A. A. HAMILTON". 473 



fully supplied with root hairs, an exceptional provision in the 

 salt-marsh plants. 



The faculty of excreting hygroscopic salts by means of salt 

 glands is ascribed to certain saltmarsh and desert plants by 

 various investigators who are not, however, in agreement as to 

 the role of this function. A theory which finds some accept- 

 ance is, that the excreted salt crystals absorb water from the 

 atmosphere and deliquesce, the plant absorbing the moisture 

 through stem or leaves. It has also been maintained 

 that the plant is merely ridding itself of an accumulation of in- 

 jurious salts. 



When drying specimens of S. australis for mounting, the 

 writer observed that salt crystals, formed in the stems, had rup- 

 tured the epidermis in several places, and were protruding 

 through the apertures. The turgidity of the Salicomia varies 

 with the salt content of the soil, numerous experiments showing 

 that the plants lose much of their succulence when grown in 

 ordinary garden soil. The halophytic tendency of the genus is 

 exemplified by its Avorld-wide distribution in saline stations. Of 

 the 9 species of Australian Salicomia 7 are shrubby; 1 is an 

 annual, and 1 a perennial herb; 5 are exclusively interior species 

 and 3, including S. australis, are coastal; 1 species, S. arbuscula 

 R . Br., is coastal in Victoria, and an interior species in New 

 South Wales. The Salicomia is distributed by currents; the 

 iruiting spikes fall at maturity with the seeds in situ and float 

 away on the tide. (This character is not so well developed in 

 S. australis as in some other members of the genus . ) Discussing 

 the dispersal of S. australis, Miss Cooke (4, p. 361) says, "When 

 the seed is ripe the fleshy perianth persists, the cell-contents dis- 

 appear, and the cell-walls become thickened by regular bands 

 which run in different directions in different cells, and the cells 

 are filled with air. This is evidently an adaptation for dis- 

 persal ; for by means of this persistent perianth the seeds float 

 on the top of the water for a long time. Seeds were placed in 

 fresh water, and at the end of a week only 3 per 1 cent, of them 

 had sunk." [Seeds of this species with the perianth removed 

 sank in a few hours in fresh water. — A. A. H.] Guppy (13, 

 p. 545) notes that the seeds of S. herbacea germinate in sea 

 water more readily than fresh, and the sea water seedling is 

 much the more vigorous and healthy of the two ; he remarks : 

 "The floating seedlings can evidently disperse the species." 



