Montana Field Guide

Stems prostrate to ascending, 5–20 cm from a simple caudex. Basal leaves rosulate, ovate to oblanceolate, 1–5 cm long, entire. Stem leaves linear to narrowly oblanceolate. Vestiture of 4- to 6-rayed short-stalked hairs. Petals 6–9 mm long. Fruit globose, 3–5 mm high, style 2.5–4 mm long; seeds 4 to 7 per locule; pedicels curved down, 5–10 mm long. Our plants are variety arenosa (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Great Plains Bladderpod - Physaria arenosa
*Pedicles are recurved downward 5-10 mm long.
*Fruits are globose not 2-lobed, 3-5 mm high
*Basal leaves on the outside are oblong to narrowly ovate, not spatulate, and 1-5cm long with entire margins.

Thick-leaf Bladderpod – Physaria pachyphylla, SOC
*Pedicels curve upwards (ascend), 3-10 mm long.
*Fruits inflated, not 2-lobed, and narrowly elliptic to ovoid, 3-6 mm tall. Style is more than half the length of the fruit (silicle).
*Basal leaves have distinct petioles and blades. Blades are spatulate to oblanceolate in shape, nearly 1 mm thick and cupped (but not folded), and with entire margins [key characteristic].
*Plants grow on pinkish or reddish soils derived from limestone on exposed slopes and ridges in valleys.

Sparsely vegetated, sandy soil of grasslands, steppe; plains, valleys (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).