Linaria bimaculata (Cout.) Farminhão & Carapeto 2024

Farminhão, João & Carapeto, André, 2024, A new combination for a neglected member of Linaria subsect. Versicolores (Plantaginaceae, Antirrhineae) endemic to the Algarve, Portugal, PhytoKeys 243, pp. 31-45 : 31-45

Linaria bimaculata (Cout.) Farminhão & Carapeto , comb. et stat. nov.

Figs 1 , 2

Basionym.

Linaria viscosa var. bimaculata Cout. , Notas Fl. Portugal III: 10 (1916).

Type.

Portugal. Algarve: Faro, February 1915, R. Palhinha & F. Mendes s. n. (lectotype LISU [ LISU 33258 !], designated here, Fig. 1 ; isolectotypes LISE [ LISE 83092 !], PO [ PO 20408 !]) .

Description.

Annual herb; somewhat glaucous, glabrous, except for glandular-pubescent inflorescence, hairs 0.4–0.5 mm. Fertile stems 1–3 (– 8), (4.6 –) 18–33.3 (– 41.8) cm long, decumbent to ascending or erect, simple or 2–4 (– 10) - branched; sterile stems (1 –) 4–10 (– 29), (1.6 –) 3.9–8.5 (13.6) cm long, prostrate to decumbent, simple, sometimes forming a dense rosette. Leaves of fertile stems (3.3 –) 6–13.9 (– 30.6) × (0.4 –) 0.7–1.3 (– 2.5) mm, linear, flat to revolute, obtuse to ± acute, alternate, sometimes the intermediate in whorls of 3; leaves of sterile stems (1.8 –) 3.4–8.6 (– 17.8) × (0.3 –) 1–2.1 (– 3.1) mm, linear to ovate, flat, in whorls of 3 (– 4). Inflorescence racemose, rachis up to (2 –) 2.6–4.3 (– 6.2) cm long in fruit, green or red, with (1 –) 4–7 (– 14) flowers, lax in flower and fruit. Bracts (2 –) 2.3–2.8 (– 3.4) × 0.2–0.4 mm, linear, acute, glabrous or glandular. Pedicels (3.7 –) 5.2–7.8 (– 9.6) mm long in flower, (3.4 –) 6–9.4 (– 12.9) mm long in fruit, erect, not adnate to the inflorescence axis, red. Calyx lobes (2.2 –) 2.3–2.9 (– 3) × (0.4 –) 0.7–0.9 (– 1.1) mm in flower and (2.4 –) 2.9–3.5 (– 4.1) × (0.6 –) 0.8–1.1 mm in fruit, subequal, glandular-pubescent, linear-lanceolate, acute, green sometimes red-tinged with whitish scarious margin. Corolla personate, spurred, (13.1 –) 14.8–17.6 (– 19.8) mm long, deep yellow with 2 longitudinal brownish red to blackish brown stripes on the throat, and an orangey palate, sometimes with brownish red spots or reticulate markings, without conspicuous dark veins; tube (1.9 –) 2.4–3.2 (– 3.7) mm broad in dorsiventral section, erect-patent; upper petals broadly ovate, divergent, slightly reflexed; spur (5.7 –) 7.9–9.6 (– 10.9) × 1–1.6 (– 1.9) mm (the width measured at the base), straight or slightly curved, equalling to slightly shorter than the rest of the corolla. Capsule (2.1 –) 2.4–3.1 × (1.6 –) 2–2.8 mm, globose, glabrous, loculi equal; style 2.1–2.5 (– 3.2) mm long, persistent, bifid at apex. Seeds (0.5 –) 0.6–0.7 × 0.4–0.5 (– 0.6) mm, wingless, pyriform-triquetrous, transversely ridged, alveolate, black. 2 n = 12.

Habitat and distribution.

Linaria bimaculata is endemic to coastal central Algarve, from Galé (Albufeira) in the west to Pinheiro (Tavira) to the east, up to 50 m a. s. l (Fig. 3 ). Its distribution is centred on the Plio-Pleistocene medium to coarse grain siliceous sands and gravels of the Ludo Formation ( Moura and Boski 1994) in central Algarve. It occurs mostly on clearings and at fringe of Pinus pinea L. and P. pinaster Aiton woods and scrubland with Ulex argenteus subsp. subsericeus (Cout.) Rothm. , Stauracanthus spp. and Cistus spp. ( Costa et al. 1996; Pereira et al. 2007; Carapeto 2020). Linaria bimaculata integrates psammophilic communities protected from the direct influence of sea spray, where characteristic species include mostly ephemeral annuals, namely Tuberaria guttata (L.) Fourr., Tolpis barbata (L.) Gaertn., Briza maxima L., Silene scabriflora Brot. , Plantago bellardii All. , Rumex bucephalophorus L., Marcus kochia-triloba (L.) Al-Shehbaz and Ornithopus pinnatus (Mill.) Druce , described as the association Tolpido barbatae - Tuberarietum bupleurifoliae, endemic to the Algarve ( Costa et al. 1996).

Phenology.

Flowering from December to June (September), peaking between January and April. Fruits develop mostly from March to June.

Conservation assessment.

Linaria bimaculata presents a restricted distribution range in coastal central Algarve. The EOO comprises 271.8 km 2 and the AOO is 152 km 2. The population faces several threats, including urban and touristic development, agricultural intensification, and the expansion of alien plants and nitrophilous communities as result of human disturbance. These ongoing threats are responsible for continued declines in the area and quality of the habitat. A continued decline in population size and AOO can also be inferred from the habitat loss and from disappearance from historical collection sites (e. g. near Faro). Considering the urban / touristic expansion within its distribution range as the main cause of habitat loss and fragmentation, only eight locations are identified, therefore this plant is assessed as Vulnerable, fulfilling the criteria B 1 ab (ii, iii, v) + 2 ab (ii, iii, v).

Notes.

Coutinho (1916) does not cite any type material in the protologue of Linaria viscosa var. bimaculata , but only one gathering, R. Palhinha & F. Mendes s. n. from Faro, can be regarded as original material, with duplicates at LISE, LISU and PO. The duplicate at LISU is labelled with a Latin diagnosis in Coutinho’s handwriting matching the protologue in Portuguese, therefore being here selected as the lectotype. Besides the type collection, the only other specimen determined as Linaria viscosa var. bimaculata by Coutinho, R. Palhinha & F. Mendes s. n. ( LISU) from Ilha das Lebres (Olhão), was only collected after the original publication of this taxon. The reticulate pattern of the palate (Fig. 2 E ) described in the type material (Fig. 1 ) is absent from most individuals observed in the field, which present an immaculate palate, being absent altogether in some populations. The apparent absence of spatial structure of this trait (i. e. reticulate vs immaculate palate) suggests it is best interpreted as polymorphism.

Linaria algarviana , hypothetically the closest relative of L. bimaculata based on flower and habit similarity, presents multiple, although rare, colour morphs (Fig. 4 ), which are here illustrated for the first time. Darker flowers (Fig. 4 A, B ) occur on the western part of its range (Aljezur, Vila do Bispo). Flowers with an erect-patent corolla tube, similar to those of L. bimaculata , occur sporadically towards the eastern part of its range (Loulé). Also, there are yellow-flowered individuals of L. algarviana (Fig. 4 G ), that can be distinguished from L. bimaculata by the erect corolla tube and the paler throat stripes. This colour polymorphism, involving purple, yellow and bicolour morphs is similar to the one reported in Linaria salzmannii Boiss. , another Iberian species of Linaria subsect. Versicolores ( Fernández-Mazuecos et al. 2018 a) .

Differences between L. bimaculata and other Linaria subsect. Versicolores present in the Algarve are summarised in Table 1 . Linaria bimaculata differs from L. algarviana in the more elongate fertile stems and the yellow flowers, with an invariably erect-patent corolla tube.

Additional specimens examined.

Portugal. Algarve: Albufeira, Pinhal do Concelho , próximo da praia da Falésia, terreno arenoso em pinhal, 25 Feb 1968, A. Fernandes, J. Paiva & J. Matos 10115 ( COI) ; Albufeira, estrada da Rocha Baixinha , Olhos de Água , 23 Feb 2019, M. J. Correia s. n. ( ALGU) ; Loulé, Vilamoura , pinhal em substrato arenoso, 19 Mar 1995, M. D. Espírito Santo & J. C. Costa s. n. ( LISI) ; Loulé, Vilamoura , Borjaca [aldeamento de], areias do Pliocénico , sub-bosque de pinhal manso, com Oxalis pes-caprae , Malcolmia gracilima , 9 Feb 1982, J. Gomes Pedro, A. M. Medeiros & J. P. Simões 22792 ( ALGU) ; Loulé, east of Quarteira , 7 Apr 1992, F. Billiet 127 ( BR) ; Loulé, praia do Porto Novo , 1 Mar 2008, M. D. Espírito Santo & R. Caraça s. n. ( LISI) ; Loulé, foz do Almargem , 18 Feb 2023, A. Carapeto s. n. ( COI) ; Loulé, Trafal , 18 Feb 2023, A. Carapeto s. n. ( COI) ; Loulé; entre Almancil e Vale de Lobo , pinhal, 19 Mar 1995, M. D. Espírito Santo & J. C. Costa s. n. ( LISI) ; Loulé, near Formosa Park Hotel , exist to the beach, pine grove on white and brown-ochre sand dunes with P. pinea and P. pinaster , 28 Mar 2004, L. J. G. van der Maesen 7873 ( WAG) ; Loulé, Ancão , solo arenoso sob pinhal, 5 Feb 2000, J. Rosa Pinto 436 / A ( ALGU) ; Loulé, Ancão , entre Faro e Ferreiras, base de morro areno-calcáreo com pinhal degradado, 10 Mar 1987, A. Moura 3079 ( MA) ; Loulé, Quinta do Lago , pinhal, 28 Abr 1989, J. C. Costa s. n. ( LISI) ; Faro, Ludo , 22 Feb 1986, J. Rosa Pinto 436 ( ALGU) ; ibid. loc., 22 Feb 2000, J. Rosa Pinto s. n. ( ALGU) ; Faro, S. Pedro, Monte Negro , pinhal de pinheiro-manso em solo arenoso, 3 Feb 1988, J. C. Costa s. n. ( LISI) ; Faro, cerca de Gambelas , 11 Apr 2017, P. Escobar García s. n. ( W) ; Faro, Marchil, a caminho de Armação de Arábia (salinas), pousio, areias, 2 May 1945, A. R. Pinto da Silva, C. Fontes, M. Myre & B. Rainha 904 ( LISE) ; Faro, Pinhal de Arábia , solo arenoso-argiloso, 13 Mar 1953, C. Romariz & E. J. Mendes s. n. ( COI, LISE, LISI, LISU) ; Faro, entre a cidade e a praia , 13 Jun 1961, J. Malato-Beliz & J. A. Guerra 5099 ( MA) ; Faro, 3 Feb 1846, H. M. Willkomm 1377 ( COI-WILLK, P [ P 04057111 (specimen on the right), P 04057154 ]) ; Faro, Champs sablonneux à Faro, 11 Mar 1853, E. Bourgeau 1975 ( COI-WILLK, P [ P 03440695 , P 03440739 , P 03440744 , P 04057189 ]) ; sin. loc., E. Bourgeau s. n. ( BR) ; Faro, in siccis / sabulosis collinis Algarbiae prope Faro, May 1847, F. M. Welwitsch 257 ( COI, LISU, P [ P 03440692 (3 lowermost specimens), P 03440734 , P 03440742 , P 03440743 , P 03440745 ]) ; Faro, arredores de Faro , Apr 1889, A. Moller 707 ( COI, P [ P 03950057 , P 04057181 ]) ; Faro, s. d., G. Sampaio s. n. ( P-GS ) ; Faro, estrada da Senhora da Saúde , Mar 1883, J. d’A. Guimarães s. n. ( COI) ; Faro, Santo António do Alto , Mar 1883, J. d’A. Guimarães s. n. ( COI) ; Faro, Areal Gordo , Mar 1891, J. Brandeiro s. n. ( COI) ; Olhão, Joinal , areias, Jan 1888, J. Brandeiro s. n. ( COI) ; Olhão, Ilha das Lebres , Apr 1917, R. Palhinha & F. Mendes s. n. ( LISU) ; Olhão, in pinetis siccis, solo arenoso, 3 Feb 1939, W. Rothmaler 14383 ( LISE) ; Olhão, Belamandil , pinhal, 17 Feb 2019, M. J. Correia s. n. ( ALGU) ; Olhão, Quinta de Marim , no solo greso-calcário do pinhal, 23 Feb 1986, A. Moura 2864 ( COI) ; ibid. loc., 24 May 1986, A. Moura 3021 ( COI, MA) ; ibid. loc., pinhal em areias, 3 Feb 1988, J. C. Costa s. n. ( LISI) ; ibid. loc., 12 Feb 1993, J. C. Costa s. n. ( LISI) ; Olhão, cercanias del centro de educación ambiental de Marim, claros de pinar sobre arenas, 11 Apr 2017, P. Escobar García 1160 / 2017 ( NY [not seen], W) ; entre Olhão e Tavira , Quintal de P. Pimentel, junto à estrada, 21 Apr 1956, J. Malato-Beliz 2849 ( MA) ; Olhão [ Tavira ], Fuzeta , pr. Livramento , 16 Apr 1963, B. Rainha 6005 ( LISE) ; Tavira, Livramento , 3 Apr 2024, A. Carapeto s. n. ( COI) ; Tavira , Pinheiro , 3 Apr 2024, A. Carapeto s. n. ( COI) .

Figures

Figure 1. Lectotype of Linaria bimaculata (Cout.) Farminhão & Carapeto (Palhinha & Mendes s. n., LISU 33258).

Figure 2. Overview of Linaria bimaculata (Cout.) Farminhão & Carapeto A habit (ascending form) and habitat B underside of flower with visible stripes C habit (erect form) D flowers with erect-patent corolla tube, immaculate palate and stripes visible on the underside of flower bud E flower with reticulate palate F seeds (A. Moller s. n., COI), scale bar 1 mm. Photos by M. Hansch (A), D. Frade (B, E), V. Dvořák (C), J. Neiva (D) and A. Coelho (F).

Figure 3. Distribution of Linaria algarviana Chav., Linaria bimaculata (Cout.) Farminhão & Carapeto, Linaria spartea (L.) Chaz. and Linaria viscosa (L.) Chaz. in the Algarve, in southwesternmost Iberia. Plain symbols indicate observation records and dotted symbols indicate herbarium specimens.

Figure 4. Overview of Linaria algarviana A habit B dark purple morph (Aljezur) typical of the westernmost populations C light purple morph (Loulé) D flower with erect-patent corolla tube (Loulé) E pink morph F bicolorous morph (Portimão) G yellow morph (Portimão). Photos by V. Achterberg (A, B), J. Neiva (C), J. T. Tavares (D), A. J. Pereira (E) and S. Lobo Dias (F, G).