POLYGAMIA. 211 



solved, and its genera distributed to other classes. All tho 

 genera, with perhaps two or three exceptions, might be thus 

 transferred, without doing any considerable violence to the 

 symmetry of the Linnaean arrangement. Several genera at 

 present arranged here, are of considerable importance, such 

 as the Ash, (Fraxinus,) Maple, (Acer,) Sensitive Plant, 

 (Mimosa,) &c. 



ORDER I. MONCECIA. 



GENUS Acacia. The Greek name for one of the species 

 of this genus. The species resemble those of the genus 

 Mimosa, from which they have been separated. Acacia 

 Arabica produces the gum Arabic of the shops. This is a 

 low tree with crooked stems, and withered appearance, which 

 grows in most parts of Africa. The gum exudes naturally 

 from the bark and hardens in the sun. That which comes 

 to Europe and America, is gathered, chiefly, in the Atlas 

 Mountains. 



GENUS Acer. Maple. Name, a Latin word, signifying 

 sharp, or vigorous ; probably so called because the heads of 

 war pikes were formerly made of this wood. 



This genus contains many species, several of which are 

 well known in most parts of North America. The Sugar 

 Maple, (Acer saccharinum,) is a large tree, and is valuable in 

 some parts of our country, on account of its affording sap in 

 the spring of the year, from which sugar is made. A tree oj 

 ordinary size yields from twenty to thirty gallons of sap, which 

 produces from five to eight pounds of sugar. This species 

 also affords the beautiful variety called bird's eye Maple, of 

 which cabinet furniture is made. 



Red Maple, (Acer rubrum,) also called Swamp Maple, is 

 likewise a large tree, growing in swamps and wet places. 

 The leaves are on long petioles, five-lobed, and serrated. In 

 the flowers which contain both stamens and pistils, the calyx 

 is five parted ; the corolla five petaled, the stamens eight, and 

 the styles two. These flowers produce the red samara, or 

 winged seed vessels, so conspicuous on this tree, and which 

 are called maple keys. The staminate, or barren flowers, 

 have a five parted calyx, five petals, and eight stamens, like 

 the others, but have no pistils, and hence produce no fruit. 



How does the class Polygamia differ from Monoecia and Dioecia? 

 From what plant and in what manner is gum Arabic produced? What is 

 said of the Acer, or maple genus ? 



