Ulmus L.

1. Ulmus L. View in CoL 2

Bark fissured. Flowers all hermaphrodite, appearing before the leaves on the previous year’s growth. Perianth-segments connate. Anthers purplish-red. Fruit a samara, winged all round but the wing emarginate at the apex.

There is considerable intraspecific variation in habit and leaf-shape which, combined with frequent vegetative propagation in U. minor and U. procera , often gives rise to more or less distinctive local populations, such as the taxa known as U. angustifolia (Weston) Weston , U. coritana Melville , and U. plotii Druce. Some of these have been given specific rank but intermediates between them, presumably due to hybridization, occur freely. In addition, trees presumed to be hybrids between U. minor and U. glabra are commonly found. Species and putative hybrids, both often represented by selected clones, are frequently planted as ornamental trees.

1 Pedicels 3-6 times as long as flowers; fruits ciliate, pendulous on long pedicels 5. laevis 1 Pedicels shorter than flowers; fruits notciliate, subsessile

2 Baseof longerside of leaf forminga roundedlobe± overlapping and concealing the short petiole; upper surface of lamina scabrid; seed central in the fruit 1. glabra 2 Baseof longersideof leaf notoverlappingor concealingthe petiole; seed distinctly above the middle of the fruit

3 Leaves suborbicular, scabrid to glabrescent above, with base of long side rounded; fruit orbicular 2. procera 3 Leaves obovate to oblanceolate, usually smooth above, with base of long side making a 90° turn into the petiole; fruit narrowly to broadly obovate

4 Young twigs glabrous or sparsely pubescent; leaves

± glabrous beneath, serrate 3. minor

4 Young twigs densely white-pubescent; leaves densely greyish-pubescent beneath, crenate-serrate 4. canescens