Teucrium × gutierrezii Rubí, 2023

Ruiz, Carlos Rubí & Navarro, Teresa, 2023, Teucrium × gutierrezii a new hybrid from Southeast Iberian Peninsula, a hotspots of natural hybridization of subfamily Ajugoideae (Lamiaceae), Phytotaxa 609 (1), pp. 45-54 : 47-51

Teucrium × gutierrezii Rubí , nothosp. nov. ( Figs. 1–3 )

Type:— SPAIN. Almería Province : Antenas de Aguadulce, W4°58’47.57”, N37°15’2.48” ca. 294 m elevation in Mediterranean perennial grasslands on limestone cliffs, 26 July 2022, C. Rubi (holotype MGC95353 ) ( Fig. 3 ) .

Diagnosis:—The new nothospecies is similar to T. eriocephalum subsp. eriocephalum with subprostate dense foliate vegetative stems in basal subrosette; tomentose-lanuginose indumentum of simple long wavy hairs in the stem, leaf and calyx but sparcely mixed with slight branched long hairs; leaves oblong-triangular and smaller (6– 9 × 2.5–3 mm) with subamplexical base but without rounded auricles; subsessile subspherical floral heads; calyx tomentose-lanuginose, larger (4–4.5 mm), with larger triangular acute teeths 0.8–1 mm but acuminate-cuspidate and the lower ones longer mucronates; corolla 4.5–5 mm larger with latero posterior lobes triangular-acutes, cuspidates but exceeding the laterals and a central lobe erect with auricles but longer than the laterals. The new hybrid also approaches T. lusitanicum subsp. lusitanicum in the cushion like growth form, the morphology of floral stems erect-ascending, slightly contorted, thick and yellowish or yellowish-green (not reddish as in T. eriocephalum ) and in the tomentose indumentum but differs from the latter subspecies in the absence of much branched trichomes (dendritic) and cucullate calyx teeths.

Description:—Erect subshrubs up to 30 cm high. Vegetative stems subprostate, green or grayish; floral stems erect, slightly contorted and thick, yellowish or yellowish-green, tomentose-lanuginose with long simple wavy hairs and glandular hairs mixed with sparce long slightly branched hairs. Leaves 6–9 × 2.5–3 mm, opposite, decussate, oblong-triangular, lobates from the basal third, base subamplexical without rounded auricles, revolute and deflexe at maturity, both sides lanuginose-tomentose with abundant wavy simple long hairs (1–1.3 mm). Inflorescence 25–30 cm in a thyrse of racemes with (8)10–12 verticillasters of subsessile, subspherical floral heads (6) 10 mm. Basal bracteoles 5–5.5– 6 mm, longer than the flowers, sessiles, ovates-lanceolates with revolute margins covered with long wavy simple hairs. Upper bracteoles as long as flowers, lanceolate with simple wavy hairs in the upper part. Calyx 4–4.5 mm subactinomorphic 3/2, tubular-campanulate, externally densely tomentose-lanuginose with long simple wavy hairs and glandular hairs, inside with scarce long simple wavy hairs; teeth 0.8–1 mm, triangular-acute, mucronate, the lowers longer mucronates. Corolla unilabiate 4.5–5 mm, white, latero-posterior lobes 1.2 × 0.5 mm, triangular-acutes, cuspidates, exceeding the laterals, glabrous, the central lobe 2 × 1 mm erect with auricles at the base, longer than the laterals. Fruit in four dry, one-seeded nutlets. 1 × 0.5 mm, subglobose, black and reticulate.

Etymology:—Plant dedicated to our friend and botanist, Leonardo Gutiérrez Carretero.

Phenology:— Teucrium × gutierrezii flowers July, when the two parental species, T. eriocephalum subsp. almeriense and T. lusitanicum subsp. lusitanicum , are also in flower at the type locality near Aguadulce, Almería Province, Spain.

Distribution and ecology:— Teucrium × gutierrezii ( Fig. 1 ) grows at the type locality, Antenas de Aguadulce between the both putative parentals T. eriocephalum subsp. almeriense and T. lusitanicum subsp. lusitanicum ( Fig. 1 ) in the HIC (Habitat of Community Interest) 6220-1 which correspond to Mediterranean neutro-basophilic perennial grasslands (Lygeo-Stipetea) on carbonated soils with Macrochloa tenacissima (L.) Kunth (dominant species) and Salsola papillosa (Coss.) Willk. , Salsola vermiculata L., Nerium oleander L., Sideritis pusilla (Lange) Pau , Maytenus senegalensis (Lam.) Exell and Rosmarinus officinalis L.

Diagnostic characters and natural hybridization in T. subsect. Polium :— Teucrium × gutierrezii constitutes the second record of natural intersubsectional hybridization between T. subsect. Polium ( T. lusitanicum subsp. lusitanicum ) and subsect. Simplicipilosa ( T. eriocephalum subsp. almeriense ). The first record corresponds with T × murcigerum (De Juan et al. 2023) described for the Murcia Province in Southeast Spain. Both nothotaxa share the similar intermediate hybrid characters, such as the general appearance of the species of T. subsect. Simplicipilosa, similar type of indumentum in stems and leaves, similar calyx morphology with teeths cuspidate-mucronate but differs in calyx indumentum less densely woolly tomentose in T. × murcigerum. T. × gutierrezii is morphologically similar to T. eriocephalum with the intermediate characters between the two parentals ( Table 1 , Figs. 2 ). The indumentum in stems and leaves is constitute of long simple wavy hairs and glandular hairs as in T. eriocephalum and some long weakly branched hairs intermediate between the simple ones and the branched (dendritic) hairs of T. lusitanicum . The presence of subrosette vegetative stems approaching T. eriocephalum while as the sessile and spherical floral heads. The leaves oblong-triangular, lobates with base subamplexical without rounded auricles are clearly intermediate within the two parents ( Fig. 2B ). The calyx teeth are acuminate-cuspidate as in T. lusitanicum while as with long mucronate lower teeths ( Fig. 2B ). The corolla latero posterior lobes are triangular-acutes as T. eriocephalum but cuspidates exceeding the laterals as T. lusitanicum .

In the Southeast of Iberian Peninsula T. subsect. Simplicipilosa is represented exclusively by endemic diploid species well characterized by their typical indumentum of flexuose, wavy simple hairs ( Puech 1976, Navarro & Rosua 1988, Navarro & El Oualidi 2000, Navarro 2010). T. lusitanicum is one of the species of the genus most widely distributed throughout the Iberian Peninsula and with the highest levels of ploidy ( Puech 1976, 1984, Navarro 2010) and T. eriocephalum is the most widely distributed species of the T. subsect. Simplicipilosa. However, it is the first time that they act as parents in a hybridization process.

Sympatric populations of the parental species involved in the new hybrid as well as others of the T. sect. Polium are very frequent in Almería ( Puech 1976) in the same territory where the new nothospecie was found. In arid perennial coastal grasslands from Almería Province, the parental T. lusitanicum subsp. lusitanicum is a tetraploid (2n = 54) ( Puech 1976). Most of the species of the T. subsect. Polium who act as parents in hybridization processes are polyploids, evidencing the high incidence of hybridization and polyploidy in the Iberian Peninsula as also occurs in other Iberian angiosperms genera ( Marques et al. 2017).

The East of Iberian Peninsula and specifically the Almería Province, are the main area of adaptive radiation of T. lusitanicum subsp. lusitanicum ( El Oualidi & Puech 1993) . This species is gynodioecious ( Alados et al. 1998) with obligate outcrossing between female and hermaphroditic plants that coexist within a population favoring the natural hybridization processes. Besides, all T. subsect. Polium species from the Southeast of Iberian Peninsula are gynodioecious ( Navarro 2020b), the presence of this breeding system contributes to explain the high rate of Teucrium hybrids in this territory.

The hypothesis formulated by De Juan-Perez et al. (2023) about T. × murcigerum, which establishes that the much branched hairs tends to be displaced by the simple (or weakly branched) hairs after hybridization processes into T. subsct. Polium and subsect. Simplicipilosa, is validated in this new discovered hybrid T. × gutierrezii .

Additional material studied:

Teucrium eriocephalum subsp. almeriense :— SPAIN. Almería Province: Rambla de la Cagüela, 330 m elevation, 30SWF4579, 25 June 2010, J.F. Mota, Pérez-García & F. Martínez-Hernández (HUAL 24689); Rambla Belén, 105 m elevation, 30SWF4579, 27 June 2017, F.J. Pérez-García (HUAL 27839); Carboneras, Central Térmica de Endesa, 80 m elevation, 30SWF9693, 17 October 2017, A.J. Mendoza-Fernández & Martínez-Hernández (HUAL 27840); Almería Capital, subida a la urbanización Espejo del Mar, 18 June 2011, M. Cueto & G. Blanca (HUAL 24194); Sierra de Gádor, Castala, Calizas, 10 April 1986, T. Navarro ( MGC 45241); Sierra de Gádor, 01 June 1997, T. Navarro ( MGC 45248); Enix, 13 May 1986, T. Navarro ( MGC 46535); Castala, 15 July 1989, J. L. Rosúa & T. Navarro ( MGC 39596); Entre Turón y Benínar, 30SVF98, 16 May 1981, M. López Guadalupe, G. Marín, J. Molero & F. P. Raya (GDA15768- 1); Sierra de Gádor, Berja, 21 June 1934, Hno. Jerónimo (GDA 32742-1). Granada Province: Almegíjar, próx. puente sobre el Guadalfeo, 11 June 1978, 30SVF7383, J. Molero Mesa (GDA 9745).

Teucrium lusitanicum subsp. lusitanicum :— SPAIN. Almería Province: Enix, 13 May 1986, T. Navarro (ALME 8036); Aguadulce, 11 August 1984, T. Navarro (GDAC 2304); El Caballar, 04 April 1984, T. Navarro ( MGC 38972); San Telmo, 01 May 1987, T. Navarro, ( MGC 39165); San Telmo, 04 Mars 1985, T. Navarro ( MGC 38761); San Telmo, 04 October 1986, T. Navarro ( MGC 46246); Cerro Majano, 04 February 1985, T. Navarro ( MGC 66994); Aguadulce, 05 July 1983, T. Navarro ( MGC 38846); Aguadulce, 08 November 1984, T. Navarro ( MGC 38845).

Figures

FIGURE 1. Habitus (A) and floral stem details (B) of parental and hybrid Teucrium taxa. 1. Teucrium lusitanicum subsp. lusitanicum; 2. Teucrium × gutierrezii; 3. T. eriocephalum subsp. eriocephalum. All from the type locality Antenas de Aguadulce, Almería Province, Spain.

FIGURE 2. Leaves (out side) (1) and dissected calyx (inner side) (2) morphology of parental and hybrid Teucrium taxa. A. Teucrium lusitanicum subsp. lusitanicum; B. Teucrium × gutierrezii; C. T. eriocephalum subsp. eriocephalum.

FIGURE 3. Holotypus Teucrium × gutierrezii from Herbarium MGC (Málaga University, Spain).