Erect, branching stems covered with coarse, spreading hairs reach 4 feet tall with elongated, one-sided clusters of small blue to white flowers. Blooms have 5 petal-like, rounded lobes with a distinctive raised yellow center. Note the flower pedicels (stems) curve downward so the flowers and seeds line up along one side of the stem. The tall stem and large leaves help identify this species.

FLOWER: June–August. Elongated, one-sided cluster of pale blue to white flowers from leaf axils and stem tips; flowers have 5 petal-like lobes that spread open to 5/16 inch wide (4–8 mm), with a raised, yellow center. Seeds are small nutlets 1/8 inch long (4 mm), with a line of barb-tipped prickles along the edge (not on the surface) (use lens). The prickles snare onto clothes giving the plant its common name.

LEAVES: Basal leaves often wither by flowering; stem leaves alternate. Blades narrow, linear-oblong to elliptic, 2–8 inches long, (5–20 cm); leaves get smaller up the stem, sessile (no stem at leaf base). Leaf surfaces are covered with short, flat-lying hairs.

HABITAT: Sandy, gravelly soils; open forests, wet and dry meadows, canyons, grasslands, pastures, roadsides; pinyon-juniper, pine-gambel oak, ponderosa-Douglas fir, mixed conifer, spruce-aspen forests.

ELEVATION: 5,570–9,900 feet.

RANGE: All states west of Rocky Mountains.

SIMILAR SPECIES: Livermore Stickseed, H. pinetorum, in much of the same NM range, has nutlets with prickles both on the edges and surface (use lens), and most leaves have stems (petioles). Flat-spine Stickseed, Lappula occidentalis, has flowers and fruit on erect pedicels.

NM COUNTIES: Western half of NM in mid- to high-elevation habitats: Bernalillo, Catron, Colfax, Grant, Hidalgo, Lincoln, Los Alamos, Mora, Otero, Rio Arriba, San Juan, San Miguel, Sandoval, Santa Fe, Sierra, Socorro, Taos, Torrance.