Cockroach plant

Haplophyton cimicidum A. de Candolle var. crooksii L. D. Benson, Torreya 42: 9. 1942

Shrubs or subshrubs 2–6 dm. Leaves: petiole 1–2 mm, pubes­cent; blade ovate-elliptic to narrowly oblong-elliptic, (7–)20–35 × (2–)4–8 mm, membra­nous, base broadly obtuse, apex acuminate to obtuse and mucronulate, surfaces pubescent. Peduncles 8–10 mm, pubescent. Flowers: calyx lobes linear-lanceolate, 5–8 mm, pubescent; corolla eglandular-pubescent abaxially and adaxially, tube 6–9 × 1.5–2 mm, lobes spreading, obliquely obovate, 10–18 × 5–10 mm. Follicles 50–90 × 1.5–3 mm. Seeds 5–7 × 0.8–1 mm.

Flowering spring–fall; fruiting summer–fall. Rocky slopes in desert scrub and desert grasslands; 700–1600 m; Ariz., N.Mex., Tex.; Mexico (Chihuahua, Coahuila, Sonora).

According to G. E. Burrows and R. J. Tyrl (2013), extracts of the dried leaves of Haplophyton, mixed with cornmeal or molasses, have been used as an insecticide and in lotions for parasite control. M. A. Mroue et al. (1996) isolated 15 indole alkaloids from H. crooksii and demonstrated that all showed significant in vitro inhibition of acetylcholinesterase activity.

Many authors have treated Haplophyton as a mono­specific genus, but J. K. Williams (1995) offered a con­vincing argument that plants from the southwestern United States and northern Mexico, characterized by sinistrorse corolla aestivation, smaller leaves and seeds, and shorter corolla tubes, and here referred to H. crooksii, represent a taxon distinct from H. cimicidum of central and southern Mexico and Guatemala. Haplophyton crooksii is widespread in southern Arizona but is known from only a few locations in Luna County, New Mexico, and El Paso and Presidio counties, Texas.