WIND-POLLINATED PLANTS 69 
taneously, the pollen they discharge into the water floats up to the surface. 
Zannichellia, allied to the ‘sea-grass’ is probably also hydrophilous. 
Kerner (‘Nat. Hist. Pl,’ Eng. Ed. 1, II, pp. 130-2) has given the following 
somewhat different account of the process of pollination in some of the above- 
mentioned plants. Although the surface of the water is very near, the’ pollen of 
Vallisneria spiralis, which consists of sticky clumps, is not easily wetted, for the three 
petals that are underneath serve as boats, which are swayed by the gentler oscillations 
of the water without capsizing. These little skiffs are driven here and there by 
the wind, and in the neighbourhood of any fixed body. If the bays of a Vallisneria 
stigma projecting above the water happen to be the landing-place, then the skiffs 
lie alongside, and it necessarily follows that some of the pollen-cells remain hanging 
on the marginal fringes of the stigmatic lobes. Transference by the wind of 
adhesive pollen carried on boats formed from floral leaves, is at present known 
to occur not only in the widely distributed species Vallisneria spiralis, but also 
in V. alternifolia, a native of tropical Asia, in Enalus acoroides of the Indian 
and Pacific Oceans, in Hydrilla verticillata, and in Elodea canadensis, as well as 
in a few species of the genus Lagarosiphon occurring at the Cape and in tropical 
Africa; only thirteen species in all, belonging to the small family of Hydro- 
charidaceae. 
According to this account of Kerner, the species just named form, in respect 
of their floral arrangements, a transition to the next group. 
II. Winp-PoLtinaTeD PLants, ANEMOPHILAE (An). 
Sprengel (‘Entd. Geheimn.,’ pp. 29-32) long ago set forth the characteristic 
peculiarities of wind-pollinated flowers (see p. 7). In insect-pollinated plants 
the pollen-grains are sticky, and their exterior is studded with knobs, spines, or 
other projections, facilitating adhesion to the body of an insect; the relatively small 
stigma also possesses a sticky surface. But in wind-pollinated plants the pollen-grains 
are smooth, dry, and dust-like, so as easily to be blown about; the branches of the 
stigma are richly provided with brush-like or feathery outgrowths, this being 
a special adaptation for catching the wind-borne pollen, which is produced in 
very great abundance. Nor do wind-pollinated flowers need any means of allure- 
ment, and therefore possess no showy parts, but are inconspicuous, odourless, 
and devoid of nectar’. The anthers are loosely suspended from the tips of the 
long thin filaments (see Fig. 9), or else the whole male inflorescence is in the 
form of an easily movable catkin. More rarely the individual flowers are pendulous, 
1 A few wind-pollinated flowers, e.g. Plantago media, are conspicuous to a certain extent, and 
receive a corresponding amount of attention from insects. I have described these as wind flowers 
(‘ Bliitenbesucher,’ i, p. 9); they form a transition to insect flowers. The more conspicuous they are, 
the more numerous are the visits of insects. Melanostoma mellina Z. shows in the highest degree 
a special preference for wind-pollinated plants (such as: Anthoxanthum odoratum Tas Phleum 
pratense Z., Alopecurus pratensis Z., Poa annua L., Festuca pratensis Z., Agrostis alba Z., Scirpus 
palustris Z., Artemisia Dracunculus Z.). The untiring and ubiquitous honey-bee also seeks out as 
booty the pollen of many wind-pollinated plants, which occurs abundantly in still weather. The 
more conspicuous species of Plantago are also sought out by humble-bees, and on the wind flowers 
of Plantago media Z. may be seen a mixed gathering of bees, flies, and beetles (op. cit., p. 10). 
