THE ROMANCE OF SEED-SOWING. 133 



brought down from the mountainous districts, and deposited 

 among the level plains and grassy meadows, and thus we can 

 easily account for the presence of such species in what seem to 

 us strange habitats for them. Both in marine currents and in 

 rivers, the action of water in carrying seeds to a?iy purpose is most 

 effectual when the direction is from W. to E., or the opposite, 

 because then, the seeds are kept pretty much within the same lati- 

 tude and therefore in similar climates. Hence they will grow and 

 flourish where they eventually settle as well as they did in their 

 former home. Currents going from N. to S. or S. to N. take 

 them into unfavourable surroundings, and then they mostly perish. 



Some seeds are specially fitted for water transit by the pre- 

 sence of air-bladders variously developed — e.g., those of Water-lily. 

 Others have a smooth rind with an oily juice, such as those of 

 Arrow-head {Sagittaria), of our water-ditches. This peculiarity is, 

 of course, of advantage in swampy and marshy districts, where the 

 water dries up in warm weather, and the courses of the current 

 vary so much, 



II. — Winds. — In many ways we see the action of this second 

 agent. The simplest cases are those where the seeds (or their 

 equivalents) are infinitesimally small, and of exceeding lightness. 

 Thus, the spores of Fimgi, Lichens, Mosses, and Ferns are 

 easily carried by the wind to distant places ; and so the members 

 of some of the above-named Orders have an almost world-wide 

 range. 



Some seeds of Flowering plants are also light enough to be 

 thus transported, or else they have some mechanical contrivance 

 to render them so. One of our little Corn-salads ( Valerianella 

 auricula), whose fruit contains three cells, developes only one 

 seed, the remaining two empty cells acting as a kind of balloon to 

 the fruit, and most likely facilitating their movement by the wind. 

 Then, again, there are seeds which are flat and very thin. 

 Those of Yellow-rattle, a parasite on meadow-grasses, afford an 

 example. The wind shakes them out of their bladder-like capsule 

 at ripening-time, and carries them to a distance, where they find a 

 congenial resting-place. 



Coming to more familiar and more easily-seen contrivances, 

 we find the winged fruits and seeds, known to most of us. 



