Reference to Matricaria inodora is made under [Note 18].

NOTE 17 (page [35])
The Buoyancy of the Seeds or Fruits of the Group of British Littoral Plants that frequent Salt Marshes and Muddy Shores

Aster tripolium. The achenes, with or without the pappus, sink in fresh and salt water in a day or two even after a year’s drying.

The small seeds, or the seed-like nucules as in Suæda, have but little floating power even after prolonged drying.

Salicornia herbacea. Would be dispersed probably by floating portions of the plant, which, however, soon break down and the liberated seeds sink. The floating seedling thrives in sea-water and could be carried great distances (see [Note 19]).

Salsola kali. I experimented on this plant, both on the coast of Devonshire and in Chile, with the same results in both localities whether in the fresh state or after drying for weeks. The fruit sinks, but when the plant dries the fruit is often detached inclosed in the perianth, and floats in that condition in sea-water for a few days. Portions of the plant of various sizes bearing mature fruits all sank within ten days. It would seem at first sight, from the observations of Prof. Martins, that the fruits float for several weeks; but his experiments were mainly directed to testing the powers of germination after sea-water immersion; and it is often not at all clear whether flotation is implied or even to be correctly inferred. There is a slight suspicion of germination on the plant. Sea-birds doubtless aid in the dispersion of this plant; the dry crisp portions of the plant carrying fruits catch readily in one’s clothes on account of the prickly-pointed leaves.

Scirpus maritimus. The fresh fruits float a few weeks in sea-water in most cases, but 10 per cent. remain afloat after two months. After drying for some months 30 per cent. remain floating after two months’ immersion.

The fruits float a few days or a week. Drying somewhat increases the buoyancy. Sir W. Buller in New Zealand found in the gullet of Anas superciliosa, the Grey Duck, numbers of the fruits of Triglochin triandrum.