a. Flowering branch. b. Hairs from adaxial leaf surface (left) and abaxial surface (right). c. Petiole with basal stipules and distal glands. d. Umbel showing one flower bud. e. Flower, posterior petal uppermost. f. Posterior petal (left) and posterior-lateral petal (right), adaxial views. g. Part of androecium, abaxial view, the longer stamens opposite sepals. h. Gynoecium, anterior style in center. i. Fruit with two of the three samaras developed. Scale bar equivalents:
a, 4 cm; b, 1 mm; c, d, 4 mm; e, f, 5 mm; g, h, 2.7 mm; i, 2 cm.—Based on: a–c, Madsen 63796, MICH; d–h, Harling 3002, MICH; i, Gentry & Dodson 54847, MICH. Drawn by Karin Douthit. First published in Contr. Univ. Michigan Herb. 23: 73. 2001; reproduced with permission of the author.