ACERACEJS. ] 75 



nists, the small adjoining family of Hippocastanece, which, like the 

 Maple tribe, contains a small number of trees or shrubs from the 

 northern hemisphere. The Bladder-nut of our shrubberies (Staphylea 

 pinnata, Eng. Bot, t. 1560), from central and eastern Europe, is the 

 type of a third tribe of Sajoindacece, in which, as in the Maples and 

 Horse-chestnuts, the leaves are always opposite, whilst in the true Sa- 

 pindacea? they are generally alternate. 



I. MAPLE. ACER. 



Trees, with opposite, palmately -veined and lobed leaves, no stipules, 

 and small, greenish flowers, in axillary corymbs or racemes. Sepals 

 usually 5, overlapping each other in the bud, and more or less united 

 at the base. Petals 5, or sometimes 4, or entirely wanting. Stamens 

 about 8, inserted on a thick disk below the ovary. Ovary 2-lobed or 

 rarely 3-lobed, each lobe enclosing one cell with 2 ovules suspended 

 from the inner angle. Styles 2, rarely 3, often united at the base. 

 Emit separating when ripe into 2, rarely 3, indehiscent carpels or nuts, 

 produced into a wing at the top, and called keys or samaras. Seeds 1 

 or 2 in each carpel, without albumen. 



A genus not numerous in species, but extending over Europe, Rus- 

 sian and central Asia, and North America. It differs from all British 

 trees, except the Ash, by its opposite leaves, and from that genus by 

 the flowers, and by the palmate not pinnate leaves. 



Flowers on short, loose, erect corymbs. Wings of the carpels 



diverging horizontally 1. Common M. 



Flowers in pendulous racemes. Wings of the carpels erect, 



parallel or slightly diverging 2. Sycamore M. 



The A. platanoides and A. monspessulanum from eastern or southern 

 Europe, the sugar Maple (A. saccharatum), from North America, and 

 some other exotic true Maples, besides the ash-leaved Maple, forming 

 the genus Negundo, from North America, may be met with in our 

 parks and plantations. 



1. Common Maple. Acer eampestre, Linn. (Eig. 218.) 



(Eng. Bot. t. 304.) 



When full-grown, a rather handsome, round-headed, though not 

 very tall tree, with a dense, dark-green foliage, but, as it is of slow 

 growth and flowers when young, it is often seen as a small scraggy 

 tree, or mere bush, in our hedges. Leaves on slender stalks, 2 to 3 



