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| Linaria almadensis Farminhão, in Farminhão, 2026. |
ABSTRACT
A new species of Linaria subsect. Supinae is described from the Tagus mouth cliffs (TMC), located about 2 km south of Lisbon, in the municipality of Almada. The taxonomic treatment, including a key to morphologically allied species, is followed by a report on the vegetation of the TMC. Linaria almadensis, historically identified as L. glaucophylla, L. marginata, L. tristis, L. polygalifolia, L. aeruginea, and L. supina, is endemic to these coastal cliffs, formed during the Pleistocene, where it grows on sandy walls in the vicinity of carbonate rocks. It is associated with a chasmo-chomophytic community including some Portuguese endemics (Silene longicilia) or near-endemics (i.e. Antirrhinum linkianum, Calendula suffruticosa subsp. lusitanica), requiring legal protection under Annex I to the Habitats Directive. Linaria almadensis is most similar to L. tristis subsp. marginata, and L. supina s.l. from which it differs by the narrowly elliptic-oblong to elliptic-oblanceolate leaves, with an obtuse-apiculate apex, and the wider corolla tube in lateral section . Bees of the genus Anthophora are here reported as pollinators of L. almadensis, and evolutionary hypotheses for its origin are discussed. Due to its restricted distribution and pressing threats to its habitat, including invasive species and infrastructural encroachment, L. almadensis is preliminarily red-listed as Critically Endangered. The existence of a narrow endemic on the brink of extinction, one priority habitat at the European level, and a rich geological heritage in the TMC, call for the urgent definition of a new protected area in one of the most densely inhabited areas of Europe.
KEYWORDS: Iberian Peninsula, melittophily, periurban biodiversity, plant conservation, plant taxonomy, rupicolous vegetation, seed morphology, Tropaeolum majus
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| Linaria almadensis in situ. (A) Habit. (B) Detail of inflorescence in early anthesis; spurs pale yellow. (C) Plant in late anthesis and fruit. (D) Detail of inflorescences in early anthesis; spurs tinged in violet. Taken at Cristo-Rei, 31 March 2021 (A, B, D) and Banática (C), 22 April 2025. Image credits: João Farminhão. |
Linaria almadensis Farminhão sp. nov.
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| Overview of Linaria almadensis. A. Habit. B. Branched fertile stem in flower and fruit. C. Fertile stem apex with inflorescence, detail. D. Fertile stem leaf, adaxial surface. E. Fertile stem leaf, abaxial surface. F. Inflorescence axis, detail of indumentum. G. Bract. H. Calyx indumentum, detail. I. Flower, frontal view. J. Flower, lateral view. K. Capsule, pedicel, and axis. L. Capsule, detail of apex. M. Seed, view of convex face. N. Seed, transversal section. A, G drawn from Arsénio s.n. (LISI053150); B – E, H, M, N from Farminhão 395 (COI00112046); F, I – L from Farminhão 371 (COI00112045). |
João Farminhão. 2026. Linaria almadensis (Plantaginaceae, Antirrhineae): A highly threatened New Toadflax endemic to the Tagus mouth cliffs, opposite Lisbon (Portugal). Botany Letters. 173(2); 251-267. DOI: doi.org/10.1080/23818107.2025.2608732 [19 Jan 2026]
