BOEHMERIEAE

Wilmot-Dear, C. M. & Friis, I., 2013, The Old World species of Boehmeria (Urticaceae, tribus Boehmerieae). A taxonomic revision, Blumea 58 (2), pp. 85-216 : 86

TRIBUS BOEHMERIEAE

The definition of the tribus Boehmerieae used here is the one proposed by Friis (1993), with the modifications by Kravtsova (2009: 12–24, 342–345). Its two largest genera are Pouzolzia and Boehmeria . Species of Boehmeria are normally perennial herbs, shrubs or small trees with opposite or alternate leaves and petiolate or sessile lamina; the leaves of a pair in the opposite-leaved species or two leaves next to each other in the alternate-leaved species may be almost identical or dimorphic. The flowers are always unisexual and variously arranged in axillary clusters or in clusters along spike-like or paniculate flowering axes (modified stems). The male flowers have 3–5(–6) more or less free perianth-lobes, the same number of stamens and a pistillode. The female flowers consist of a perianth which completely encloses the ovary; the stigma is filiform and pro- trudes from the opening of the perianth. The female perianth persists during the ripening of the fruit, a moderately thin-walled and smooth, but dull rather than shiny achene, which remains completely enclosed in the perianth at maturity, only partially filling the fruiting perianth.

Species belonging to the genus Boehmeria are distinguished from species of most other genera in the tribe by their filiform rather than capitate stigma, but confusion may occur with the identification of Pouzolzia , Pipturus and Cypholophus , which also have a filiform stigma.

Pouzolzia often differs in its caducous stigma and strongly longitudinally ribbed perianth, but the only absolute distinction is its shiny rather than dull achene easily detachable from perianth at maturity and (usually) caducous stigma; the major differences between the two are in the anatomy of the fruiting perianth and outer layers of the achene ( Kravtsova et al. 2000, 2003, Kravtsova 2001, 2009, Wilmot-Dear et al. 2009). Pipturus is distinguishable only by the pistillate perianth, which is succulent at maturity with a dark opening, a ‘dark hole’, at the apex after the early-caducous stigma has fallen. Cypholophus differs mainly in the minute tightly curled stigma and fleshy fruiting perianth. The morphological relationships between these three genera are dealt with in key form in Friis (1993: 618 - 619) and discussed in more detail in Wilmot-Dear (2009).