Leaf or leaflet surface hairiness (lower)

The presence or absence of hairs on the leaf or leaflet lower surface. Note that this character, and the previous one (upper leaf or leaflet surface indumentum) refer generally to horizontally compressed leaves. For vertically compressed leaves, upper and lower surfaces are not distinguished. If hairs are present on both surfaces, both upper and lower surfaces are treated as hairy. If hairs are present on only one surface, both upper and lower surfaces are treated as glabrous or hairy. For terete or tetragonal or trigonous leaves, it may be difficult to distinguish the upper and lower surfaces (particularly when leaves are apparently solid), and in these cases, both surfaces are treated as hairy when hairs are present. Leaves with marginal hairs only (e.g. some Urodon species) are treated as glabrous or hairy as is the case when hairs are restricted entirely to venation.

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Glabrous

The lower leaf or leaflet surface is visible, without hairs or with a few scattered hairs.

Hairy

The lower leaf or leaflet surface is slightly to entirely obscured by hairs.