Montana Field Guide

Stems ascending, 3–20 cm. Herbage strigose to villous with non-septate, long-pointed hairs. Leaflets 5–12 mm long; stipules 0.5–3 mm long. Flowers: sepals 3–5 mm long; petals yellow, 6–8 mm long. Capsule 1–2 cm long, pubescent with retrorse hairs; seed ridges white (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Montana has 3 Oxalis species.

Dillen's Wood-sorrel - Oxalis dillenii, likely native
*Habit: A tall, erect forb with short, simple rhizomes. Stems do not root at the leaf nodes.
*Hairs: Long pointed (strigose to villous) but without cross-walls; hairs not septate.
*Capsules: Covered with stiff, straight, sharp, and appressed hairs (strigose).

Creeping Wood-sorrel - Oxalis corniculata, exotic
*Habit: A tall, erect forb with short, simple rhizomes. Stems root at the leaf nodes.
*Hairs: Sparsely strigose to strigose-villous to villous, but without cross-walls; hairs not septate.
*Capsules: Sparsely covered with long, stiff (hirsute) hairs.

Common Yellow Wood-sorrel - Oxalis stricta, likely exotic
*Habit: A tall, erect forb with short, simple rhizomes. Stems do not root at the leaf nodes.
*Hairs: Multi-cellular with purple cross-walls (septate).
*Capsules: Sparsely covered with long, stiff (hirsute) hairs.

Lawns, gardens, fields, streambanks; plains, valleys (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus pensylvanicus (Colla and Dumesh 2010).