19. Oakesia. Stem angled. Leaves sessile. Flowers opposite the leaves. Capsule acutely 3-winged.
[+][+] Stem or scape from a bulb or corm; capsule many-seeded.
20. Erythronium. Scape from a solid bulb, with a pair of leaves. Flower solitary. Seeds angled, obovoid.
21. Lilium. Stem leafy from a scaly bulb. Seeds horizontal, flattened.
[*][*][*] Fruit a berry; stem from a tuber-like rootstock, bearing 1 or 2 whorls of leaves; flowers terminal; stigmas sessile.
22. Medeola. Leaves in 2 whorls. Flowers umbellate. Perianth-segments similar, colored, deciduous.
23. Trillium. Leaves (3) in a terminal whorl. Flower solitary; outer sepals leaf-like, persistent.
Series C. Floral bracts green or greenish (rarely scarious), or none. Stamens at the base of the distinct 1–several-nerved persistent perianth-segments; anthers small, versatile. Styles or sessile stigmas distinct. Capsule mostly septicidal. Seeds with a loose testa or appendaged. Leaves with transverse veinlets (except in n. 24 and 25).
[*] Stems leafy or bracteate, from a thick tuberous rootstock; flowers racemose; anthers 2-celled; stigmas linear.
24. Helonias. Leaves radical, oblanceolate. Flowers perfect. Capsule broadly obovate, many-seeded.