A deciduous, very leafy tree, from 50 to 65 ft high, forming a dense rounded head of branches; buds rough, grey; young shoots ordinarily without down. Leaves 5 or 8 in. long, with five to nine leaflets which are ovate or oblong (the terminal one obovate), 2 to 4 in. long, 3⁄4 to 13⁄4 in. wide, more or less tapered at the base, abruptly pointed at the apex, shallowly round-toothed, dull green and glabrous above, the base of the midrib beneath and the stalk downy; main-stalk grooved above, furnished with brownish down where the leaflets are attached. Flowers whitish, very abundantly produced in May in terminal and axillary panicles 3 or 4 in. long, along with the leaves of the new shoots; petals linear, 1⁄4 in. long. Fruits about 1 in. long, narrow-oblong.
Native of S. Europe and Asia Minor; cultivated since early in the 18th century, if not before; now one of the best known of exotic trees. It is a handsome tree with very luxuriant leafage, and decidedly ornamental in flower, although the blossom has a faint, not agreeable odour. Manna sugar is obtained from the stems by incision.
The manna ash is somewhat variable in the wild, mainly in the shape and size of its leaflets, which may be relatively broader or longer acuminate at the apex, than in the tree described above, but it is doubtful if these fluctuations are worthy of taxonomic recognition. A more distinct geographical variant is:
var. rotundifolia (Lam.) Ten. F. rotundifolia Lam. – Of dwarfer habit than the type with the leaflets about 1 in. long and broadly rhombic-elliptic. Found in Calabria, the Balkans, etc.
How effective the manna ash can be as a specimen is well shown by the group at the east end of the Lake at Kew. The largest here is 45 × 71⁄2 ft (1964). There are two manna ashes in Hyde Park, London, measuring 66 × 71⁄4 ft and 57 × 71⁄2 ft, and another in Kensington Gardens of 75 × 63⁄4 ft (all 1967). Others of note are: Beauport, Sussex, 50 × 91⁄2 ft (1965); Frogmore, Berks, 45 × 83⁄4 ft (1967); Whiteknights, Berks, 62 × 5 ft (1962); Melbury, Dorset, 45 × 8 ft (1967).