HEPTANDRIA. 139 



GENUS Rumex. Dock. This genus contains many spe- 

 cies which differ greatly from each other in most respects. 

 They grow from one to six or eight feet high. In most of 

 the species the root is fusiform, but in some it is tuberous. 

 The broad-leaved Dock, (Rumex obtusifolius,) is one of the 

 most pernicious of weeds. It always prefers cultivated 

 places, and the best soil in the neighborhood. Any rich 

 neglected spot, which has once been occupied, is sure to be 

 o^ errun with this plant. It is not a native of our country, but 

 has been introduced from Europe, in every country of which 

 it is to be found. In this country this species grows from 

 two to five feet high ; leaves oblong-cordate, obtuse, the 

 edges crenate. All the species of this genus produce large 

 quantities of seed, by which new plants are propagated from 

 year to year, and unless the young plants are destroyed the 

 first year, by being pulled up by the roots, they shoot so deep 

 as to make it difficult to do this afterwards. These roots are 

 so tenacious of life, and so prolific, that when cut in pieces, 

 they will not only grow again, but each piece will produce a 

 new plant. 



CLASS VII. HEPTANDRIA. Stamens 7. Orders 4. 



Fig. G. 

 b 



This is a small class, and contains 

 no genera of any considerable impor- 

 tance. The Horse Chestnut, and the 

 Trientalis are among the best known. 



ORDER I. MONOGYNIA. Stamens 7. Style 1. 

 GENUS jEsculus. Horse Chestnut. Esculus, was the 

 name of a tree which furnished the Latins with an esculent, 

 or eatable nut. It is called Horse Chestnut, (Hippocasta- 

 num,) because this nut was formerly employed as a medi- 

 cine for horses. There are several species of this genus, of 

 which the Esculus hippocastanum, or common Horse Chest- 

 nut, is the largest and most beautiful. This tree came ori- 

 ginally from the northern parts of Asia, and has migrated 

 to this country by the way of Constantinople, Vienna, Italy, 



What is the botanical name of dock ? Is dock a native of America, or 

 not ? What is the origin of the name horse chestnut ? 



