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1 Flowers borne only in (false-)terminal racemes of (1-) 2-7 flowers; leaf margins entire to 3-lobed; hairs of the leaf undersurface with longest arms to 1 mm long; of c. TX, mainly Edwards Plateau but edging into our region]; [series Styrax].
..2 Lower leaf surfaces glabrous except for scattered, orange-brown or dark-brown, stalked, stellate hairs abaxially on some; pedicels and calyces glabrous.
..2 Lower leaf surfaces with scattered, white, stellate pubescence in addition to scattered, orange-brown or dark-brown, stalked, stellate hairs; pedicels and calyces with white, stellate hairs.
1 Flowers borne in both (false-)terminal racemes as well as some borne axillary to well-developed leaves; leaf margins glandular serrate with a few to many teeth; hairs of the leaf undersurface with longest arms to 0.6 mm long; [collectively widespread in our region, e. TX and se. OK eastwards]; [series Cyrta]
......4 Leaves generally broadly obovate, sometimes broadly ovate, 5-14 cm long, 4-10 cm wide, the apices acute to short-acuminate, densely and finely pubescent beneath, giving the underside of the leaf a pale color; inflorescence usually of 5-20 flowers
......4 Leaves narrowly elliptic to ovate or obovate, usually 2-8 cm long, 1-4 cm wide, the apices short- to long-acuminate, glabrous or sparsely pubescent beneath (to densely pubescent and then giving the underside of the leaf a rusty color in var. pulverulentus); inflorescence usually of 1-7 flowers.
........5 Leaves oblong-elliptic, glabrous or sparsely pubescent on the undersurfaces and petioles, the margins usually distantly toothed toward the apices; pedicels 10-14 mm long; calyces essentially glabrous; new growth glabrous to sparsely pubescent
........5 Leaves elliptic to ovate to oblanceolate or obovate, sparsely to densely scurfy-hairy on the undersurfaces and petioles, margins entire to serrate; pedicels 4-6 mm long; calyces and pedicels densely scurfy-hairy; new growth densely matted pubescent