Verbascum delphicum Boiss. & Heldr. subsp. cervi Zografidis (Scrophulariaceae, Scrophularieae) is described as a subspecies new to science and illustrated. It is narrowly distributed in the Greek National Park of Mt Parnitha (Attica, Greece) with a very small population size. The new subspecies is a seldom-collected taxon, previously overlooked and misidentified as consubspecific with the autonymous subspecies, an endemic of the island of Evvia (Greece). Also described in this study is a new variety of subsp. delphicum from Mt Ochi of southern Evvia.

Verbascum , new subspecies, endangered taxon, Mt Parnitha

Comprising more than 360 species, Verbascum L. (Scrophulariaceae) is the largest genus of the predominantly northern temperate tribe Scrophularieae Dumort. (= Verbasceae Dumort.) and is chiefly represented by rosulate, biennial or perennial herbs with yellow-flowered, thyrsic or racemose inflorescences (Fischer 2004; Oxelman et al. 2005). Although the genus is widely distributed in Eurasia and North Africa, species diversity is mostly concentrated in a region encompassing Anatolia, Caucasus, northwestern Iran, the Levant and the southern Balkans (Murbeck 1939). In Greece, Verbascum is among the 10 most species-rich and the 10 most range-restricted-rich genera with a total of 76 species and an endemism rate of 32% (Dimopoulos et al. 2013).

Verbascum was extensively studied by the Swedish botanist Svante Murbeck who published two monographs on Verbascum and Celsia L. — now merged in Verbascum — and a series of two additional, supplementary and interpretative studies on the genus (Murbeck 1925; 1933; 1936; 1939). Since his era, several other species have been discovered and described, principally but not exclusively from Anatolia (AI-Hemaid 2001; Aytaç and Duman 2012; Bani et al. 2010; Çeçen et al. 2015; Davis 1951; 1952; Firat 2015; Greuter and Rechinger 1972; Huber-Morath 1939; 1949; 1955; 1960; 1965; 1967; 1971; 1973; 1974; 1975; 1976; 1979; 1981; 1983; Karavelioğullari 2015; Karavelioğullari et al. 2011; Karavelioğullari et al. 2004; Karavelioğulları et al. 2009; Karavelioğullari et al. 2008; Karavelioğullari et al. 2014; Kaynak et al. 2006; Parolly and Eren 2008; Parolly and Tan 2007; Ranjbar and Nouri 2015; Sotoodeh et al. 2015; Sotoodeh et al. 2016; Stefanova-Gateva 1979) and a modified classification system of “informal, partly artificial groups” has been utilized by Arthur Huber-Morath for the Turkish taxa (Huber-Morath 1978). Both taxonomies of Murbeck and of Huber-Morath are still widely cited and used today in studies of new species; however, it should be noted that a first assessment of molecular data suggests these schemes are non-natural and that the genus has potentially been subjected to taxonomic inflation (Ghahremaninejad et al. 2014).

Verbascum delphicum Boiss. & Heldr. was discovered by Theodor von Heldreich on Mt Dirfi of the island of Evvia (West Aegean Islands, Greece) and was subsequently jointly described by himself and Edmond Boissier in Boissier’s Diagnoses plantarum Orientalium novarum (Boissier 1856). The autonymous subspecies is a nemoral, short-lived perennial or biennial herb with often impressive, sizeable basal leaves. Knowing the taxon well from my excursions on the mountains of central and south Evvia I was surprised to find on Mt Parnitha (Attica, Sterea Ellas, mainland Greece) on May 2013 a small population of a closely related, yet distinct and undescribed as it appeared to be taxon. The population consisted of biennial plants with noticeably smaller and more or less differently shaped leaves than those of the insular V. delphicum. Inspection of the mainland population in the past recent years and comparison with the insular populations revealed some additional deviating traits for the taxon on Mt Parnitha. Taking into consideration overall morphology and the common habitat and phenology of the two taxa, as well as the phytogeographic connection between Sterea Ellas and Ins. Evvia, I propose that collectively the differences indicate distinction at the subspecies rank.

The new subspecies V. delphicum subsp. cervi Zografidis described and illustrated in this work was apparently overlooked and misidentified by Murbeck as consubspecific with subsp. delphicum based on material collected by Heldreich and Bassilios Tuntas from Mt Parnitha. The differences between the two subspecies are presented and discussed. A new, distinct variety of subsp. delphicum from Mt Ochi, south Evvia is also described.

For the cultivated material current-year seeds were sown in early October (2013 & 2015), in small pots filled with Compo® Bio Anzucht- und Kräutererde substrate. Two-weeks old plants were individually transferred in plastic pots 7 cm of diameter and were transplanted every c. 8 weeks two additional times in successively larger plastic pots, 15 and 24 cm of diameter. The plants were kept outdoors, daily receiving 5 hours of direct sunlight on average, whereas the substrate was kept moist but not soggy.

Measurements were performed either with a common ruler or under a stereo-microscope (Zeiss, Stemi 2000-C) equipped with a camera and ImagePro software. Because the population size of the new subspecies is extremely small the measurements were either performed in situ without damaging the plants, or, when this was not feasible, only small plant-parts were collected for subsequent assessment under the stereo-microscope. In particular, two flower-clusters (glomerules) of the middle part of the inflorescence were removed from 20 individual plants i) at flowering and ii) at fruiting. Statistical significance was assessed with two-tailed T-tests for two independent means (p<0.01) and two-tailed Mann-Whitney U-tests (p<0.01).

The differences between V. delphicum subsp. cervi and subsp. delphicum are presented in Table 1, whereas a comparative illustration is presented in Figure 2. A three-year field survey of both insular and mainland populations and examination of cultivated plants confirmed the constancy of the distinctive features. Subspecies cervi is characterized by its smaller and more elongated leaves with the base of leaf-laminas obtuse to long-cuneate — vs. ± truncate or even cordate in subsp. delphicum — and by a shorter, harsher and darker indumentum. Another significant character is the color of the stamen filaments: either greenish-white in subsp. cervi or deep-orange in subsp. delphicum. I note that this character is almost lost with drying. Life-cycle is an additional interesting trait. In his Flora Orientalis, Boissier has cited V. delphicum as a biennial herb (Boissier 1856), a vague conception which has been perpetuated in various floras ever since (Ferguson 1972; Raus 1986). Although biennial individuals are indeed found among its populations, the autonymous subspecies is more frequently a short-lived perennial herb as evidenced by the concomitant existence of the flowering stem and either of an additional leaf-rosette or of a previous-year withered infructenscence or of both on the same plants. On the other hand, subsp. cervi has clearly drifted towards the biennial life-cycle and very rarely do the plants exceed the usual two years lifespan — I have seen only two such individuals.

On Mt Parnitha and on the mountainous region of central Evvia — Mts Dirfi and Xirovouni — V. delphicum inhabits Greek-fir or mixed Abies-Castanea woodlands, flowers from early-mid-June to early-mid-August and matures seeds from July to August. On Mt Ochi of southern Evvia the species is found in open Castanea woodlands — Abies is absent from southern Evvia — or in sub-montate to montane, open shrublands dominated by thick patches of Pteridium aquilinum ferns. In these habitats of Mt Ochi, I have found that subsp. delphicum frequently produce sterile stems instead of basal leaf rosettes; the unusual trait gives a quite distinctive appearance to the plants but apart from it they are indistinguishable from typical individuals that grow in proximity. I propose this taxon to be classified as a new variety of subsp. delphicum (Figure 3 and Suppl. material 2). The variety might have evolved from the competition for sunlight inside the dense patches of ferns of these habitats, whereas I have never found it in central Evvia — not even in the shadier spots where subsp. delphicum produces the typical basal rosettes.

Murbeck’s assumption that typical V. delphicum existed on Mt Parnitha was based on the following material he cited in his monograph: i) a collection by Heldreich — “Parnes, reg. abiet. occid., leg. HELDREICH 1854, n. 2902 [Hb. Berl.]” — even though Heldreich himself never reported V. delphicum from mainland Greece and the date of the collection, which has unfortunately been destroyed during World War II (Th. Raus, personal communication, 27 August 2015), precedes by two years that of the original description of the species; ii) three collections by collector Bassilios Tuntas — “Parnes, reg. abiet., occid., leg. TUNTAS 5/7/1911, n. 1247 [Hb. Hal.; Hayek].- Mt Parnes, prope cacumen, leg. TUNTAS 21/7/1907, n. 356 [Hb. Hal.]; 13/6/1909, n. 810 [Hb. Hal.]” — which, however, were not found either in WU-Generale, WU-Halácsy-Graecum or WU-Halácsy-Europaeum (W. Till, personal communication, 15 March 2016). Perhaps the only surviving voucher is kept in the Gothenburg Herbarium and likely corresponds to the aforementioned n. 1247 specimen of the collector, although the serial number is missing. Nevertheless, on the sheet there is a label with Murbeck’s name and handwriting that states “V. delphicum”. Having seen the specimen I have no doubt it represents subsp. cervi on account of the characteristic small basal leaves with an obtuse-cuneate base and the short indumentum. It is interesting to note that the aforementioned specimen includes the whole aerial part of a plant arranged on a single sheet, which is actually feasible for a medium individual of subsp. cervi — e.g., see the Holotype, Suppl. material 1. On the contrary, a medium individual of subsp. delphicum is impossible to completely fit on a voucher sheet because the basal leaves are too big. I conclude that on Mt Parnitha there exists a single infraspecific taxon of V. delphicum, namely subsp. cervi, allopatric to the insular subsp. delphicum which is confined to Evvia. The species had not been collected from the mainland for almost a century, but its existence was confirmed by a recent floristic study on the mountain (Aplada et al. 2007), (E. Aplada, personal communication 1 September 2016). Other reports of V. delphicum from the mainland — from the Peloponnese cited in (Dimopoulos et al. 2013) or from Mt Pendeli cited in (Vladimirov et al. 2012) — are in error (Th. Raus, and K. Polymenakos, personal communications respectively). The distribution map of V. delphicum is presented in Figure 4.

Figure 4. 

Distribution map of Verbascum delphicum: ■subsp. cervi; ●, ○subsp. delphicum; ○var. filictorum.

Both infraspecific taxa of V. delphicum described in this study are distinct and easily recognized, whereas the species closest relative remains unknown. Subspecies cervi is apparently a critically endangered taxon.

I am grateful to: P. Koubetsos and K. Polymenakos for the useful discussions on interesting Verbasca of Mt Parnitha; Th. Constantinidis and P. Bareka for their notes on speciation; P. Livanos and S. Samaropoulou for the technical aid and their welcoming smile.