A New Mirandea (Acanthaceae) from Nuevo Leon, Mexico

Abstract

Mirandea huastecensis is described from Huasteca Canyon in west-central Nuevo Le6n. The subfamilial status of the genus is discussed. A character tabulation comparing the two species of Mirandea is included together with illustrations of the diagnostic morphological features of M. huastecensis. Rzedowski (1959) described the genus Mirandea, containing the single species M. grisea. He noted the vegetative and floral relationships of this genus to Carlowrightia A. Gray and Anisacanthus Nees, but was uncertain of its tribal affinities based on the pollen. Since Rzedowski's treatment, Bremekamp (1965) has sought to clarify the tribal situation in the Acanthaceae with respect to pollen morphology. In his scheme, Mirandea falls within the circumscription of the tribe Justicieae, subtribe Odontoneminae with Carlowrightia and Anisacanthus. It differs from both of these genera by having stamens with twisted filaments and an apically geniculate style. Mirandea may be further distinguished from Carlowrightia by the position of the stamens which are appressed to the upper lip of the corolla in Mirandea and are either enclosed in the central, conduplicate petal lobe of the lower lip or exserted and spread beyond the recurved petal lobes in Carlowrightia. Mirandea also differs from Anisacanthus by its pubescent capsule, filaments and style, and by the blue or purple corolla which is 12 to 20 mm long. In Anisacanthus, the capsule, filaments and style are glabrous, and the corolla is bright red or orange and 30 to 55 mm long. On examining material of these genera, I encountered collections representing an undescribed species of Mirandea from northern Mexico which is presented below. Mirandea huastecensis T. F. Daniel, sp. nov. Planta fruticosa, usque ad 1 m alta, valde ramosa. Caules striati, pubescentes. Folia subsessilia, lamina plerumque ovato-elliptica vel ovatolanceolata, 3-10 mm longa, 1-5.5 mm lata, circa 2-4-plo longiora quam latiora, apice rotundata vel acuta, basi cuneata, margine ciliata. Inflorescentiae numerosae, rachidibus canescentibus. Bracteae anguste ovatae vel anguste ellipticae, 2-4 mm longae, 0.8-1.5 mm latae. Corolla roseolapurpurea, 12-20 mm longa, bilabiata, labio superiore erectiusculo apice bidentato, labio inferiore trilobato. Stylus geniculatus. Capsula 8-11 mm longa, puberula. Semina 3.5-4.0 mm longa, 2.5-3.0 mm lata, granulata, muricata. 1 Botany, University of Michigan, Ann Arbor, MI 48109.