ORDER MONOGYNIA. '233 



closeness of the grasp, has expired, the leaf again unfolds itself. 

 These movements are accounted for, by attributing to the 

 plant a power of irritability, which is excited by the touch of 

 any object. Although we account for the phenomenon by 

 attributing it to the irritability of the plant, we have only re- 

 moved the difficulty by adducing a cause which itself remains 

 to be explained. We shall in a future lecture make some 

 remarks upon the irritability, or as it is sometimes called, sen- 

 sibility of plants ; many curious and interesting facts, respect- 

 ing this singular property of vegetables, may be collected ; 

 many plausible theories to account for it have been given ; 

 but the efficient cause is too deep for man to penetrate ; his 

 feeble faculties cannot comprehened the designs and opera- 

 tions of Almighty Power. 



The Second Order of the tenth class contains the Hydran- 

 gea, an elegant East Indian exotic ; a species of this plant, a 

 shrub with white flowers, is said to have been found on the 

 banks of the Schuylkill river. 



The Pink (Dianthus) belongs to an extensive natural order, 

 Caryophyllete, which is distinguished by having five petals in- 

 serted with claws. One native species of the genus Dianthus, 

 called armeria, or Wild Pink, has been found in New Jersey 

 and New England. 



The Third Order, or Trigynia, contains some plants which 

 belong to the same natural order as the pink. 



The Fourth Order, Tetragynia, is not important. 



The Fifth Order, Pentagynia, produces a plant, Agrotfemma, 

 known by the name of Cockle ; this is very common in fields ; 

 although troublesome, and regarded but as a weed, it is a 

 handsome pink-like plant, bearing a deep red or purple blos- 

 som ; in its genuine character it differs little from the genus 

 which contains the pink, except in having five pistils instead 

 of two, on which account it is placed in the fifth order. 



Here is also found the Sorrel (Oxalis), which produces the 

 oxalic acid, similar in its properties to the juice of lemons ; 

 though poisonous, this acid is useful in taking the stains from 

 linen. 



In the Tenth Order is the Poke-weed (Phytolacca), a very 

 common plant ; the fruit of which consists of large, dark ber- 

 ries, often used by children for the purpose of colouring purple. 

 The young shoots are tender, and are sometimes eaten as a 

 substitute for asparagus. The flower of this plant presents us 

 with 10 stamens, 10 styles, a calyx with 5 white leaves resem- 

 bling petals, a berry superior (above the germ), with 10 cells 

 and 10 seeds. 



Hydrangea Pink Cockle Sorrel Poke-weed. 

 20* 



