Peritoma arborea

(Nuttall) H. H. Iltis
Novon 17: 449. 2007.
Common names: Bladderpod bladderbush burro-fat
Basionym: Isomeris arborea Nuttall in J. Torrey and A. Gray, Fl. N. Amer. 1: 124. 1838
Synonyms: Cleome isomeris Greene
Treatment appears in FNA Volume 7. Treatment on page 206. Mentioned on page 199, 205.

Shrubs (evergreen), 50–200 cm. Stems profusely branched; glabrate or puberulent (bark corky, twigs smooth). Leaves: petiole 1–3 cm; leaflets 3, blade oblong-elliptic, 1.5–4.5 × 0.4–1.3 cm, margins serrate, apex acuminate to obtuse, surfaces glaucous. Racemes 1–3 cm (6–40 cm in fruit); bracts unifoliate, obovate to spatulate, 2–15 mm. Pedicels 7–15 mm (thickened in fruit). Flowers: sepals persistent, connate ca. 1/2 of length, green, lanceolate, 4–7 × 2.2–4 mm, margins entire, glabrous; petals yellow, ovate-elliptic, 8–14 × 4.2–5 mm, (apex acute); stamens yellow, 15–25 mm; anthers 2–2.5 mm; gynophore (reflexed), 10–20 mm in fruit; ovary 3–6 mm (often aborting in bud); style 0.9–1.2 mm. Capsules (tardily dehiscent), usually inflated,(valves sometimes 3), 20–30 × 6–12 mm, smooth. Seeds 5–25, dark brown, obovoid, 6–7 × 5–6 mm, smooth.

Distribution

V7 271-distribution-map.gif

Ariz., Calif., nw, w Mexico.

Discussion

Varieties 3 (3 in the flora).

Peritoma arborea is woody and is variable in fruit size and shape. The large variability in fruit shape has led to the naming of varieties (L. D. Benson and R. A. Darrow 1945).

Key

1 Capsules not inflated, narrowly fusiform. Peritoma arborea var. angustata
1 Capsules inflated, obovoid or subglobose > 2
2 Capsules inflated, obovoid. Peritoma arborea var. arborea
2 Capsules strongly inflated, subglobose. Peritoma arborea var. globosa