1881. 



on Fruits and Seeds. 



025 



corkscrew, and ending in a long and beautiful feather, the whole 

 being more than a foot in length. The long fcatlier, no doubt, facili- 

 tates the dispersion of the seeds by wind ; eventually, however, they 

 sink to the ground, which they tend to reach, the seed being the 

 heaviest portion, point downwards. According to Darwin, tlic seed 

 remains in the same position as long as it is dry, but if a shower comes 

 on, or when the dew falls, the spiral unwinds, and if, as is most pro- 

 bable, the surrounding herbage or any other obstacle prevents the 

 feather from rising, the seed itself is forced down and so driven by 

 degrees into the ground. 



I do not doubt that this seed may bury itself in the manner thus 

 described, but I do doubt whether it always, or indeed generally, does 

 so. One fine day not long ago, I chanced to be looking at a plant of 

 this sj^ecies in my garden, and round it were several seeds more or 

 less firmly buried in the ground. There was a little wind blowing at 

 the time, and it struck me that the long feathery awn was admirably 

 adapted to catch the wind, while on the other hand it seemed almost 

 too delicate to drive the seed into the ground in the manner described 

 by Darwin. I therefore took a seed and placed it upright on the turf. 

 The day was perfectly dry and fine, so that there could be no question 

 of hygroscopic action. Nevertheless, when I returned after a few 

 hours, I found that the seed had buried itself some little distance in 

 the ground. I repeated the observation several times, always with 

 the same result, and thus convinced my- 

 self that one method, at any rate, by -piG. 22. 

 which these seeds bury themselves is by 

 taking advantage of the action of the 

 wind, and the twisted portion of the awn 

 by its corkscrew-like movement probably 

 facilitates the entry of the seed into tho 

 ground. 



I have already mentioned several cases 

 in which plants produce two kinds of 

 seeds, or at least of pods, the one being 

 adapted to burying itself in the ground. 

 Heterocarpism, if I may term it so, or 

 the power of producing two kinds of re- 

 productive bodies, is not confined to these 

 species. There is, for instance, a North Nat^Sizo 

 African species of Corydalis (C. hetero- 

 carim of Durieu) which produces two Seeds of Corydalis 



kinds of seed (Fig. 22), one somewhat hcterocarpa. 



flattened, short and broad, witli rounded 



angles ; the other elongated, hooked, and shaped like a shepherd's 

 crook with a thickened staff. In this case the hook in the latter form 

 perhaps serves for dispersion. 



Our common Thrinda liirta (Fig. 13 h) also possesses, besides tho 

 fruits with the well-known feathery crown, others which are destitute 



