THE COMMENCEMENT OF THE PHANEROGAMIC FRUIT. 71 



)ermatoplasm is segmented up into many fragments; these escape from the 

 itheridium and reach the simple fruit-rudiment by swimming. Since the sper- 

 latozoids are attracted to the young fruits by certain excretions which the latter 

 iss out into the water, the multifarious devices associated with aerial fertiliz- 

 iion are unnecessary. Protective coats around the sexual organs, sheaths to limit 

 raporation, brightly-coloured or sweet-smelling floral-leaves to attract insects that 

 ley may transfer the pollen from flower to flower — all these are wanting in 

 lants which are fertiHzed under water. Now it is just these accessory protecting 

 ;ructures which constitute what are called blossoms. Thus we can say that 

 lese water-plants have no blossoms. To avoid misconception it must be stated 

 lat although they have no blossoms they have flowers. For although, popularly, 

 lossoms and flowers are used as synonymous terms, under flowers are compre- 

 ended the organs which are concerned in fertilization, under blossom merely the 

 iaves which inclose the essential organs and which guard and protect the young 

 raits and stamens. It is these latter which produce the sexual protoplasts, 

 "heir union is promoted by the leaves of the blossom. Sometimes they catch 

 he pollen-grains as they are blown by the wind, or by the production of honey 

 nd scents attract insects which remove the pollen in their visits. In other 

 ases, by projecting ridges and comers, they are instrumental in detaching the 

 oUen from these same insects, and in a thousand ways protect and assist the 

 ifficult process of aerial fertilization. 



In the above lines we have been speaking not of aquatic plants generally, 

 ut of such as are fertilized under water. And these should be carefully distin- 

 uished. Many aquatics, which pass their lives under water, send up their 

 owers to the surface so that their fertilization is aerial. On the other hand, 

 trange though it may seem, the fertilization of most aerial Lichens, Mosses, and 

 'ems which grow on the sand of desolate moors, on the sunny rocks of mountain 

 ides, or on the dry bark of old tree stems, is accomplished under water. Plants 

 f this sort may be exposed to drought for many months, and the movement of 

 ap within them may be suspended; but when they are moistened with rain or 

 ew they are quickened and rejuvenated, and form their young fruits and 

 ntheridia. Things are so arranged that the liberation of the spermatozoids 

 oincides with the moment at which these plants have access to sufiicient 

 loisture. Thus we see that it is literally true of these plants — whether growing 

 n the bough of a tree or in a ravine on a mountain side — that their fertilization 

 J accomplished under water. 



The only really important distinction between plants permanently submerged 

 nd such as are thus situated from time to time, is that in the latter the young 

 jxual organs are protected against desiccation during the periods of exposure by 

 leans of sheathing structures and leaf-like scales, as is particularly well shown 

 y the Mosses. Blossoms in the usual sense, however, are not found amongst Ferns 

 ad Mosses, and we can make the following three general statements: — (1) That 

 iryptogams are fertilized under water and most Phanerogams in the air; (2) that 



