288 



BOTANT. 



motion ; some flowers close on the approacli of moisture, hi 

 others the leaves only possess this power ; many kinds fold 

 or curl up the petals of their flowers at the close of the day, 

 and expand them with the rising morn ; a large variety only 

 expand their flowers in the middle of the day, and while the 

 sun shines ; and shoi'ld the season at which they usually 

 bloom, be wet and cold, numbers never unfold their flowers, 

 notwithstanding which their seed is perfected. As plants da 

 not possess the power of moving from the spot where they 

 first root, it would seem a circumstance of course, that their 

 seed should produce abundance of the same kind all around 

 the parent plant; but this is by no means a constant 

 occurrence ; the seed-vessels of many plants open with so 

 great a degree of elasticity, as to throw their seed to a very 

 considerable distance ; a large number of seeds are furnished 

 with plumes or wing-like appendages, which when they are 

 discharged from the pericarp, supports them in air, and they 

 are wafted by every breath, till reaching some sheltered spot 

 they vegetate, and form a new colony ; Numerous kinds 

 of seeds are covered witli pulpy substances, these are 

 devoured by various kinds of birds, who, having digested the 

 pulp, pass the seeds unconcocted, and as these have not had 

 the vital principal impaired, they readily vegetate ; some 

 kinds of seeds are provided with hooks, spines, or other ap- 

 pendages, which cause them to attach to the skins and furs 

 of Animals, and they are by this means widely distributed. 



It is observable that most plants that encrease greatly by 

 their roots, do not produce much seed, and frequently what 

 is produced is not perfect ; thus, though nature seems foiled 

 in the one instance, the plant does not perish, as the roots of 



