Prosopis ruscifolia

Name and classification

Prosopis ruscifolia Griseb.
Family Fabaceae, Subfamily Mimosoideae

NOTE: Only three seeds of Prosopis ruscifolia were available for examination. Therefore, the description and images in this fact sheet may not be representative of this species’ seeds.

Common names

mesquite

Description

Pods linear, straight to subfalcate or with a twist (S-shaped), compressed, 13–29 cm long, 9–11 mm wide, 2–5 mm thick. Stipitate, apex short-tapered to caudate, margins undulate. Smooth, speckled or streaked with darker color, longitudinal striate ridges; seed chambers 10–30. Endocarp segments boney, closed, rhombic, 5–8 mm long and wide, 1–2 mm thick; mesocarp often semi-fleshy and sweet. Seeds oriented longitudinally.

Seeds obovate to broadly or asymmetrically obovate in outline, 4–7 mm long, 3.2–4.7 mm wide, 1–2.2 mm thick, umbo not very prominent, +/– elliptic in cross section. Pleurogram average to wide. Lens a light-colored mound.

Identification considerations

Similar species

Prosopis flexuosa DC. (Pod is similar). [No image available.] (non-FNW)

Prosopis vinalillo Stuckert (Pod is similar) [No image available.] (non-FNW)

Distribution

Argentina, Bolivia, Brazil, Paraguay

Habitat

thickets, open woodlands, park-like grasslands

General information

Prosopis ruscifolia is a spiny tree, 5–12 m tall, that is considered a serious weed in Argentina. The plants form dense, spiny, impenetrable thickets that prevent livestock from grazing and result in abandonment of these lands. Livestock and herbivores relish the sweet pods, thereby dispersing the seeds widely. The leaves contain a substance that inhibits germination of other seeds. When full grown, it yields good timber.

seeds

seeds

lens and funiculus remnant of seed

lens and funiculus remnant of seed

pods

pods

pod fragments

pod fragments

A, pod; B, one-seeded endocarp segment; C, seed; D, longitudinal section of seed showing embryo; E, transection of seed; drawing by Lynda E. Chandler

A, pod; B, one-seeded endocarp segment; C, seed; D, longitudinal section of seed showing embryo; E, transection of seed; drawing by Lynda E. Chandler