Pachystachys spicata

cardinal's guard


Pachystachys spicata

(Ruix & Pav.) Wassh. 1986

pronounced: pack-ee-STACK-iss spick-AH-tuh

(Acanthaceae — the black-eyed Susan family)


common name: cardinal's guard

Pachystachys is derived from the Greek παχυς (pachys), thick, and σταχυς (stachys), an ear of corn, referring to the flowerheads; spicata is Latin, from spicatus, with spikes, ears (like grain).

Pachystachys is a genus of 12 or so species of flowering plants, native to rainforest in the Caribbean and Central and South America. They are all evergreen perennials and shrubs, with prominent terminal spikes of flowers and brightly coloured bracts. The genus is closely related to Justicia.

The plant is suffrutescent, erect or sparingly branched, 1 – 5 m tall. The stem is glabrous, terete or with the upper part subquadrangular. The petiole can be anything from 2.5 to 7 cm in length, and is glabrous. The leaf blade is firm, oblong or elliptic or broadly lanceolate, 15 – 27 by 7 – 11 cm in size, the apex acute to acuminate, but with the tip itself usually blunt, and the base narrowed either gradually or abruptly. Both surfaces of the leaf are glabrous, and the margin entire; both primary and secondary veins are rather prominent.

The inflorescence is a solitary terminal spike from 12 to 22 cm long; the rachis is finely puberulous; the bracts imbricate, green, ovate-lanceolate in shape, up to 25 by 11 mm in size, with the terminal bracts smaller. They have acuminate apices, narrowed at the base, have a short petiole, and are puberulous, the lower surface more densely so; the bracteoles are narrowly linear.

The individual flowers are sessile or nearly so; the calyx is campanulate, the lobes narrowly triangular, with acuminate apices. The corolla is scarlet, becoming orange-red with age, 55 – 70 mm long, the tube curved, only about 4 mm wide at the base, but gradually enlarging to 8 mm at the throat; the upper lip is erect, lanceolate. There are 2 lobes, obtuse; the two protruding long stamens are attached near the base of the corolla tube, with yellow puberulous filaments. The anthers are also yellow, and deeply sagittate. The staminodes are rudimentary, and puberulous; the ovary is glabrous.

The fruit is a clavate capsule, about 16 by 5 by 4,5 mm in size, glabrous. The seeds are brownish, and flattened.

Propagation is usually by cuttings.

As well as this plant, Pachystachys coccinea and P. lutea are also found in cultivation. They can be grown outside in tropical and subtropical gardens where the temperature does not fall below 10ºC. Elsewhere, they can be grown under glass or as houseplants. In the garden, they need a shady location, in fertile, well-drained most soil.


Photographed in Arcadia, 2018
Page last updated 15th February 2019