Clipweed

Mexican populations of Ephedra antisyphilitica are disjunct from those in Texas.

Shrubs erect or spreading, 0.25--1 m. Bark gray, slightly cracked and irregularly fissured. Branches alternate or whorled, rigid, angle of divergence about 45°. Twigs green, becoming yellow-green with age, glaucous, not viscid, with numerous longitudinal grooves; internodes 2--5 cm. Terminal buds conic, 1--3 mm, apex obtuse. Leaves opposite, 1--3 mm, connate to 2/3--7/8 their length; bases thickened, brown, completely deciduous; apex obtuse. Pollen cones 1--2 at node, lance-ellipsoid, 5--8 mm, sessile to nearly sessile; bracts opposite, 5--8 pairs, pale green to red, obovate, 2--4 × 2--3 mm, membranous, connate at base; bracteoles slightly exceeding bracts; sporangiophores 4--5 mm, 1/2 exserted, with 4--6 sessile to very short-stalked (less than 1 mm) microsporangia. Seed cones 1--2 at node, ellipsoid, 6--12 mm, sessile to nearly sessile; bracts opposite, 4--6 pairs, ovate, 5--7 × 5--10 mm, connate to 1/8--7/8 their length, inner pairs becoming fleshy and red. Seeds 1(--2), ellipsoid, 6--9 × 2--4 mm, light brown to chestnut, smooth.

Okla., Tex.; Mexico in Nuevo León and San Luis Potosí.

Coning March--April. Arid soils and rocky slopes; 100--1200m.

Ephedra antisyphilitica var. brachycarpa Cory; E. occidentalis Torrey ex Parlatore; E. texana E. L. Reed

Shrub, Evergreen, Dioecious, Habit erect, Plants prostrate or spreading, Trees without or rarely having knees, Primary plant stem smooth, Young shoots 3-dimensional, Buds not resinous, Leaves scale-like, Leaves opposite, Leaves mostly not photosynthetic, Non-needle-like leaf margins entire, Leaf apex acute, Leaf apex mucronulate, Leaves < 5 cm long, Leaves < 10 cm long, Leaves yellow-green above, Leaves yellow-green below, Leaves yellow below, Leaves grey-green, Leaves not blue-green, Leaf bases deciduous, Scale leaves without raised glands, Scale leaf glands not ruptured, Scales leaves not or barely overlapping, Twigs glabrous, Twigs not viscid, Twigs without peg-like projections or large fascicles after needles fall, Berry-like cones copper, Bracts of seed cone included, Seeds tan, Seeds brown, Seeds wingless.

Ephedra antisyphilitica is a plant species native to the southern Great Plains of the United States (Oklahoma, New Mexico, Texas), and also to northeastern Mexico (Nuevo León, Coahuila, San Luis Potosí).

This species should not be confused with the 1871 name Ephedra antisyphilitica S.Wats., native to farther west in the Southwestern US and in Baja California. Meyer's use of the name dates from 1846, so it has priority over Watson's later application of the same name to a different plant. Watson's plant is now called Ephedra nevadensis.