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| Coutaportla lorenceana Torr.-Montúfar, H.Ochot. & Art.Castro, in Torres-Montúfar, Flores-Olvera, Ávila-González, Castro-Castro & Ochoterena. 2023. |
Abstract
Background and aims – Ongoing studies on Mexican Rubiaceae revealed an undescribed species of Coutaportla endemic to the Sierra Madre Occidental pine-oak forests in the state of Sinaloa, near the border with Durango, Mexico. The species is here described and illustrated, and its morphological characters are compared with those of the other species in the genus.
Material and methods – This study is based on field observations, examination of herbarium specimens including digital images, and morphological studies based on samples from dried and spirit specimens.
Key results – The morphological comparison of taxonomically important characters among the species of Coutaportla reveals conditions that were previously not reported for the genus. The placentation and ovule number of C. lorenceana, which belongs in the Portlandia complex, is comparable to that in the Chiococceae tribe. This tribe was proposed to include the latter complex based on molecular data, but the classification was controversial according to the morphology. Coutaportla lorenceana hence provides a morphological link between the Portlandia complex and the taxa traditionally placed in Chiococceae. The new species is assessed as Critically Endangered following the IUCN Red List criteria.
Keywords: Mexican flora, Neotropics, pine-oak forest, placentation, Santuario El Palmito, Sierra Madre Occidental, taxonomy
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| Coutaportla lorenceana Torr.-Montúfar, H.Ochot. & Art.Castro A. Flowering branch. B. Detail of the venation on the abaxial leaf surface. C. Stipule and immature fruiting branch. D. Inflorescence. E. Flower. F. Ovary and calyx longitudinally dissected. G. Dissected corolla. H. Androecium. I. Detail of the puberulent filaments. J. Style. K. Capsule longitudinally dissected showing seed attachment. L. Seed. Drawn by Albino Luna (A–J, from A. Castro-Castro et al. 4532; K–L from A. Castro-Castro et al. 4695). |
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| Coutaportla lorenceana Torr.-Montúfar, H.Ochot. & Art.Castro A. Habit. B. Twigs showing intrapetiolar persistent stipules. C. Flowering branch. D. Inflorescences showing corolla shape and colour. E. Longitudinal section of the ovary showing apical placentation in lateral (perpendicular to the fruit compression plane) and frontal (parallel to the fruit compression plane) views. F. Immature fruits. Photographs by Arturo Castro-Castro (A–D, F) and Helga Ochoterena (E). |
Coutaportla lorenceana Torr.-Montúfar, H.Ochot. & Art.Castro, sp. nov.
Diagnosis: Coutaportla lorenceana differs from all the other species in the genus by the lavender corollas, the apical ovule placentation, and the capsules with 1-seeded locules. It most closely resembles C. ghiesbreghtiana (Baill.) Urb. by the treelet habit and leaf size and shape, but it differs by the leaves acuminate at the apex (vs apiculate in C. ghiesbreghtiana), the chartaceous leaf blades (vs subcoriaceous in C. ghiesbreghtiana), the 3–9-flowered inflorescences (vs solitary flowers in C. ghiesbreghtiana), and the lavender corollas (vs white in C. ghiesbreghtiana).
Etymology: The specific epithet is dedicated to David Lorence, who has immensely contributed to the knowledge of Mexican Rubiaceae, establishing for the first time an enviable collection for the family at MEXU, which serves as an invaluable basis for research.
Alejandro Torres-Montúfar, Hilda Flores-Olvera, Heriberto Ávila-González, Arturo Castro-Castro and Helga Ochoterena. 2022. An Assessment of Coutaportla (Chiococceae, Rubiaceae) with the Description of A New Species from Mexico. Plant Ecology and Evolution. 156(1): 3-12. DOI: 10.5091/plecevo.89764
