228 NATURAL THEOLOGY. 



acquired a certain degree of consistency. In some water- 

 plants, the flowering and fecundation are carried on luithin 

 the stem, which afterAvards opens to let loose the impregna- 

 ted seed.^ The pea, or papilionaceous tribe, inclose the parts 

 of fructiiication within a beautiful folding of the internal 

 blossom, sometimes called, from its shape, the boat or keel — 

 itself also protected under a penthouse formed by the exter- 

 nal petals. This structure is very artificial ; and what adds 

 to the value of it, though it may diminish the curiosity, very 

 general. It has also this further advantage — and it is an 

 advantage strictly mechanical — that all the blossoms turn 

 their backs to the wind whenever the gale blows strong 

 enough to endanger the delicate parts upon which the seed 

 depends. I have observed this a hundred times in a field of 

 peas in blossom. It is an aptitude which results from the 

 figure of the flower, and, as we have said, is strictly mechan- 

 ical, as much so as the turning of a w^eather-board or tin cap 

 upon the top of a chimney. Of the poppy, and of many 

 similar species of flowers, the head while it is growing hangs 

 down, a rigid curvature in the upper part of the stem giving 

 to it that position ; and in that position it is impenetrable 

 by rain or moisture. AYhen the head has acquired its size 

 and is ready to open, the stalk erects itself for the purpose, 

 as it should seem, of presenting the flower, and with the 

 flower the instruments of fructification, to the genial influ- 

 ence of the sun's rays. This always struck me as a curious 

 property, and specifically as w^ell as originally provided for 

 in the constitution of the j^lant ; for if the stem be only bent 

 by the weight of the head, how comes it "to slraighlen itsell 

 when the head is the heaviest ? These instances show the 

 attention of nature to this principal object, the safety and 

 maturation of the parts upon which the seed depends. 



In trees, especially in those which are natives of coldei 

 climates, this point is taken up earlier. Many of these 

 trees — observe in particular the asli and the horsecliest- 

 •* Philosophical Transactions, part 11., 1796, p. 502. 



