Justicia sessilis Jacq.

• Authority

  Britton, Nathaniel L. Flora Borinqueña.

• Family

  Acanthaceae

• Scientific Name

  Justicia sessilis Jacq.

• Description

  Species Description - Restricted in distribution, in Porto Rico, to the dry southwestern and eastern districts, growing on rocky hillsides and in thickets at low elevations, this somewhat woody, herbaceous plant bears 2-lipped, attractive, purple flowers in the upper leaf-axils; it occurs also on the islands Vieques and Culebra, ranges eastward through the Virgin Islands, in the Lesser Antilles from St. Martin to Guadeloupe, and inhabits also Trinidad, Margarita and northern Colombia. We have learned of neither Spanish nor English popular names. We have not observed it above about 150 meters elevation. Justicia is a Linnaean genus of over 100 species, tropical in distribution; the name commemorates James Justice, a Scotch gardener. They are herbs, or shrubs, with opposite, untoothed leaves, their irregular flowers solitary, or clustered. The calyx is deeply 4-or-5-cleft into narrow, nearly equal segments; the corolla has a 2-lipped limb, the upper lip 2-cleft, the lower 3-cleft; the 2 stamens are borne on the throat of the corolla; the 2-celled ovary has 2 ovules in each cell, the style is slender. The fruit is an oblong or obovate capsule, which splits elastically, releasing the seeds. Justicia sessilis (stalkless flowers and leaves) is usually branched, sometimes becoming nearly a meter high, but mostly lower, often flowering when only 10 or 20 centimeters high. The stalkless, or very short-stalked, thin, ovate or elliptic leaves are from 1 to 3.5 centimeters long, sparingly hairy, pointed, or blunt, with a rounded base. The slender branches have 2 lines of hairs. The stalkless flowers are borne solitary, or 2 or 3 together in the upper leaf-axils; the lance-shaped segments of the 4-parted calyx are about 4 millimeters long; the slender tube of the purple, finely hairy corolla is about 10 millimeters long, the lips 6 or 7 millimeters long. The smooth, pointed capsule is 10 or 12 millimeters long, nearly flat, stalked. Justicia periplocifolia is also illustrated in this work, and there are 2 other species in the Porto Rico Flora, one of them known only from the small island Culebrita, the other only from Monte Cerrote.

• Discussion

  Sessile-leaved Justicia Acanthus Family Justicia sessilis Jacquin, Enumeratio Systematica Plantarum 11. 1760. Justicia parviflora Vahl, Eclogae Americanae 1: 2. 1796.