ACER 



Acer, Linnsus, Sp. PI. 1054 (1753); Bentham et Hooker, Gen. PL i. 409 (1862); Pax, in Engler, 



Pflamenretck, iv. 163, Aceracece, 6 (1902); Schneider, Laubhohkunde, ii. 192 (1907). 

 Negundo, Ludwig, Ge7t. PI. 308 (1760); Bentham et Hooker, loc. cit. 



Trees or shrubs, belonging to the natural order Aceraceae, which is often 

 considered to be a division of Sapindacese. Leaves usually deciduous, rarely 

 evergreen, opposite, without stipules simple, in which case they are undivided 

 or palmately lobed or compound with three to five leaflets. Buds covered by 

 several scales arranged in decussate pairs, or protected by two valvate scales, 

 sessile or occasionally stalked. Twigs with epidermis persisting for more than 

 one year and remaining green in the second year ; or becoming corky on the 

 surface and changing colour in the first season. Inflorescence terminal on two- 

 to four-leaved branchlets, or arising out of lateral buds without leaves, in racemes, 

 corymbs, or fascicles. Flowers appearing at the same time as the leaves or earlier ; 

 regular, dioecious, or with male and perfect flowers on the same tree, or with male 

 flowers on one tree and perfect flowers on another tree. Parts of the flowers in 

 fours or fives or multiples of those numbers. Calyx with four, five, to twelve sepals, 

 usually free, occasionally connate. Petals equal in number to the sepals, absent 

 in some species. Disc secreting honey usually present, absent in a few species, 

 annular, lobed, or reduced to small teeth. Stamens four to ten, usually eight, 

 inserted either outside the disc, inside it, or upon it. Ovary, two-lobed, two- 

 celled, each cell containing two ovules. Styles or stigmas two, free or connate 

 at the base. Fruit of two samarae, attached by their bases, with long and 

 diverging wings. Seeds one or two in each samara, without albumen ; cotyledons 

 appearing above the ground on germination. 



About no species of maple are known, occurring usually in mountainous 

 regions ; in Europe, south of lat. 62, in Algeria, Asia Minor, the Caucasus, 

 Persia, Turkestan, the Himalayas, China, Manchuria, Japan, Formosa, the 

 Philippines, Java, Sumatra, Celebes, and in North America from Southern 

 Canada and Oregon to Mexico and Guatemala. A large number have been 

 introduced into cultivation, fifty-seven species being enumerated in the Kew 

 Hand-List ; but many of these are shrubs or small trees, the detailed treatment 

 of which does not come within the scope of our work. 



The genus is divided by natural characters into thirteen sections by Pax, 



whose monograph and that of Schneider should be consulted by cultivators of the 



630 



