Phaseolus parvulus – Pinos Altos Mountain Bean

Phaseolus parvulus - Pinos Altos Mountain Bean (flower)

Phaseolus parvulus - Pinos Altos Mountain Bean (leaves)

Plant Name

Scientific Name: Phaseolus parvulus

Common Name: Pinos Altos Mountain Bean

Plant Characteristics

Duration: Perennial

Growth Habit: Vine, Herb/Forb

Arizona Native Status: Native

Habitat: Mountain. This wildflower grows in pine-oak and coniferous forests.

Flower Color: Pink, Purple

Flowering Season: Late summer, Early fall

Height: Up to 1 foot (30 cm) tall or more if climbing

Description: The flower stalks emerge from the leaf axils and have 1 or 2 pea-like flowers. The individual flowers have a broad, upright, somewhat cupped, fan-shaped banner petal and a tightly coiled, white and green keel above 2 large, paddle-shaped wing petals. The flowers are followed by hairy, green drying to brown, linear, straight, flattened bean pods with an upcurved tip. The leaves are dark green, minutely sparsely hairy, alternate, and trifoliate with 3 lance-shaped leaflets that are somewhat curved like a sickle. The stems are slender, erect to twining, hairy, and green to brownish in color. The plants grow from a plump, rounded, underground tuber.

The similar Tepary Bean (Phaseolus acutifolius var. tenuifolius) grows at lower elevations and has narrower, non-sickle-shaped leaflets, while Slimleaf Bean (Phaseolus angustissimus) has non-sickle-shaped leaflets with often a pair of subhastate basal lobes.


Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Subclass: Rosidae
Order: Fabales
Family: Fabaceae – Pea family
Genus: Phaseolus L. – bean
Species: Phaseolus parvulus Greene – Pinos Altos Mountain bean

More About This Plant

Arizona County Distribution Map