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. PI.,' Eng. Ed. i, 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. altemifolia, 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. Wind-pollinated 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, 



' 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 liave described these as wind flowers 

 (' Bliitenbesiicher,' 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 L. shows in the highest degree 

 a special preference for wind-pollinated plants (such as: Anthoxanthum odoratum L., Phleum 

 pratense L., Alopecurus pratensis Z., Poa annua L., Festnca pratensis L., Agrostis alba L., Scirpus 

 palustris L., 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 L. may be seen a mixed gathering of bees, flies, and beetles (op. cit., p. 10). 



