22 On inuring Tender Plants to our Climate. 



exposed in the open air to its severest influence ; but a peren- 

 nial has to encounter frosts with its buds and annual shoots, 

 that have sometimes been so severe with us, as to rend 

 asunder the trunks of our indigenous forest trees.* 



It is probable that Wheat, our principal food at present, did 

 not bring its seed to perfection in this climate, till hardened 

 to it by repeated sowings ; a few years ago some spring wheat 

 from Guzerat was sown with barley, in a well cultivated field ; 

 it rose, eared, and blossomed with a healthy appearance, but 

 many ears were, when ripe, wholly without corn, and few 

 brought more than three or four grains to perfection. 



In the year 1791, some seeds of Zizania aquatica were pro- 

 cured from Canada, and sown in a pond at Spring Grove, 

 near Hounslow ; it grew, and produced strong plants, which 

 ripened their seeds : those seeds vegetated in the succeeding 

 spring, but the plants they produced were weak, slender, not 

 half so tall as those of the first generation, and grew in the 

 shallowest water only ; the seeds of these plants produced 

 others the next year, sensibly stronger than their parents of 

 the second year. 



In this manner the plants proceeded, springing up every 

 year from the seeds of the preceding one, every year becoming 

 visibly stronger and larger, and rising from deeper parts of 

 the pond, till the last year, 1804, when several of the plants 

 were six feet in height, and the whole pond was in every part 

 covered with them as thick as wheat grows on a well managed 

 field. 



Here we have an experiment which proves, that an annual 

 plant, scarce able to endure the ungenial summer of England, 



* See Miller's Dictionary, article Frost. 



