Stachys virgata Bory de Saint-Vincent & Chaubard (1832: 166

Constantinidis, Theophanis, Kalpoutzakis, Eleftherios & Kougioumoutzis, Konstantinos, 2015, The rediscovery of Stachys virgata (Lamiaceae), a rare endemic of Peloponnisos, Greece: taxonomy, distribution, karyology and conservation, Phytotaxa 218 (3), pp. 241-252 : 244-247

Stachys virgata Bory de Saint-Vincent & Chaubard (1832: 166 , plate XVII)

Type (lectotype, here designated):— GREECE. Peloponnisos: Stachis [sic] virgata Chaub. et Bory, Morée , s.d., Chaubard, J.B.G.M. Bory de St-Vincent s.n. (MNHN-P-P03683987!, isolectotype G!) = Stachys zuccarinii Bentham (1834: 535) . Type:—Not designated.

Notes on typification:—We traced a few historical specimens of Stachys virgata deposited in BR!, G!, P! and WU!. On the label of one G specimen we read ‘ Stachis [sic] virgata Chaub. et Bory, Morée, Chaub. ’ in apparently the same handwriting as on the P lectotype label. Both specimens obviously comprise part of the same original gathering and it is therefore safe to consider the G specimen an isolectotype. The second specimen deposited in G-BOIS is a subsequent collection of 1844 by S.R. Lenormand. In WU, the S. virgata specimen (WU 0038150!) has the indication of an exact locality: ‘Cranidi, Morée’, followed by ‘Chaubard’ (collector?) in a handwriting different from that on P and G specimens. Since the town of Kranidi (Cranidi) is cited by Bory de Saint-Vincent & Chaubard (1832: 166) as a collection locality, WU 0038150 is obviously a syntype of S. virgata . We have not been able to trace F. Zuccarini’s collection from Akrokorinthos. Bentham (1834: 535) indicated a specimen in the K.F.P. von Martius herbarium collected ‘ in Graecia ad Acrocorintham ’ on which he based his S. zuccarinii , a later synonym of S. virgata . Von Martius’ exsiccates are primarily housed in BR and M. No material was detected in M but a specimen does exist in BR!, apparently sent to von Martius by X. Landerer and J. Sartori in 1835. On its label we read: ‘ Astros, in montib. saxosis versus coenob. Sotyri ’, which most probably corresponds to a locality ca. 4 km NW of Astros, near the convent of Transfiguration of Loukous. Both the toponym and the collectors do not match Bentham’s (1834: 535) protologue and this specimen cannot serve as a lectotype for S. zuccarinii .

Description:—Perennials forming a persisting, partly subterranean, branched, suffruticose stock 2–5 mm wide and producing 4–25 (or more in large specimens) annual stems that die back in autumn. Flowering stems 40–90(–100) cm long, quadrangular, angles yellowish-green, sides slightly concave, with decussate branches at almost every node of main axis up to inflorescence; primary branches placed at an angle of 30–50º to main stem and further branched similarly one or two times; all parts of stem covered with simple, soft, predominately adpressed, whitish hairs. Lower leaves mostly withered at anthesis, 7–10 × 0.8–2.5 cm, elliptic to oblanceolate-elliptic, acute to subobtuse, attenuating at base into a 2.5–4 cm long petiole, rather remotely serrulate-serrate, tomentose, veins on lower surface evident; middle and upper leaves gradually smaller and narrower, often falcate, oblanceolate to ensiform, tomentose-sericeous especially on lower surface, petiole very short to absent; uppermost leaves 10–20 × 1.5–3 mm, entire. Inflorescence (5–) 15–25 cm long, simple, rarely branched at base, sericeous particularly on upper parts; verticillasters (2–)5–18, clearly distant, those on lower parts placed at 3.0– 5.5 cm intervals, those on upper parts at 0.7–1.6 cm intervals, 1–3(–6)-flowered but predominately 2-flowered. Bracts lanceolate, acute, 7–20 × 2–3.5 mm, tomentose-sericeous, 1/2 as long to somewhat longer (at lower parts of inflorescence) than calyx; bracteoles lanceolate, acuminate, 5–7 × 1–1.5 mm, sericeous, ca. 1/2 to 3/4 as long as calyx, ending into a ca. 0.5 mm yellowish to brownish mucro. Calyx on a ca. 2 mm pedicel, regular, campanulate to somewhat infundibular after anthesis, sericeous especially at lower part and along veins, 8–12 × 3–4 mm, with 5 main veins below each tooth and 2–4 secondary veins between each pair of main veins; tube 6.5–8 mm long, hairy inside, with a dense ring of ca. 2 mm long white hairs at mouth; teeth triangular, equal, 2.5– 4.5 × ca. 1 mm at base, ending in a yellow-brownish 0.5–1 mm long mucro. Corolla bilabiate, white to cream or rarely ochre-yellow, 16–19 mm long; tube equalling to calyx, annulate inside, hairy on throat; upper lip straight, entire to shallowly emarginate, with long sericeous hairs on upper surface; lower lip 6–7 mm long, 3-lobed, with reddish-purple markings on upper surface, middle lobe largest, 4.5–5.5 × 9–10 mm at widest part, lateral lobes broadly triangular, obtuse to emarginate, ca. 2.5 × 3 mm at widest part. Stamens 4, epipetalous, ca. 6 mm long, exserted from corolla tube and shorter than upper lip; filaments with swollen hairs at lower half and with sparse sessile glands along their length; anthers dithecous, thecae divaricate. Style gynobasic, ca. 12 mm, terminal branches equal. Nutlets obovoid, 2–2.5 × 2 mm, brown to blackish, verruculose.

Distribution:—Endemic to eastern Peloponnisos (both southern and northern parts), Greece, and known from a few historical and some recent collections. The old records from the north-eastern (Akrokorinthos, Astros, Kranidi, Methana, Trizina) and southern (Cape Tenaron) parts of the region have not been confirmed for the last 171 years, but the species may still grow there in small populations. Extant populations were discovered in a relatively small stripe of eastern Peloponnisos, at the lower foothills of Mts Parnonas and Madara that face the Mirtoon Sea. The known distribution of Stachys virgata is presented in Fig. 3 . Rather interestingly, the new and historical locations are quite distant from one another; yet, the former fall within a 100 km radius from the nearest historical collection site. This phenomenon has been observed in the presumed extinction and rediscovery of other species as well ( Crowley 2011).

Habitat and ecology:— Stachys virgata was found growing in maquis clearings or openings, at an elevation of 4– 660 m a.s.l. Maquis openings are found either in primary (e.g. in stony or rocky places, where scrub establishment may be difficult) or in secondary, man-made habitats (i.e. planted olive groves receiving little cultural care and replacing natural vegetation). In several cases, S. virgata was seen along dirt roads or paths, where the natural vegetation had been cleared. Likewise, road embankments and debris offer suitable habitats for S. virgata . The species cannot tolerate competition by tall and dense maquis vegetation, therefore, it is absent or rarely found within such formations. Human interference (e.g. local fires occasionally used by land owners to clear slopes from natural vegetation) may provide new suitable niches and colonization opportunities to some S. virgata populations. In open places, roadsides and embankments, Stachys virgata occasionally grows together with Asperula elonea Iatroú & Georgiadis , a local endemic species, and other common species such as Acer sempervirens L., Arbutus andrachne L., A. unedo L., Cytisus laniger DC. , Erica manipuliflora Salisb. , Fraxinus ornus L., Globularia alypum L., Hyparrhenia hirta (L.) Stapf, Hypericum empetrifolium Willd. subsp. empetrifolium , Olea europaea L., Phagnalon graecum Boiss. & Heldr. , Phillyrea latifolia L., Quercus coccifera L., Teucrium flavum L., Thymbra capitata (L.) Cav. and Satureja thymbra L. In maquis clearings, S. virgata grows together with Bituminaria bituminosa (L.) C.H.Stirt., Cytisus laniger, Cistus salviifolius L., Erica manipuliflora , Globularia alypum , Pistacia lentiscus L., P. terebinthus L., Sarcopoterium spinosum (L.) Spach and Smilax aspera L. Stachys virgata occurs singly or in small groups, on calcareous, schistose or other, non-calcareous substrates. Its populations are usually low in number of mature individuals, rarely exceeding 20 plants ( Table 1).

Phenology:— Stachys virgata flowers from the end of May to the middle of July. The ripe seeds are released in August, perhaps also in early autumn. The annual, above-ground flowering stems die back in late autumn and new shoots appear in October and November, depending on rainfall.

Karyology:—Two plants originating from the area near Krioneri settlement (pop. no. 16) were cultivated for chromosome investigations. Both plants provided 2n = 34 ( Fig. 4 ). The chromosomes are short, usually 1 μm or less, appearing blurry and without a clear centromere position in our metaphase plates. A distinct satellite was seen and probably some more exist in the complement, but they are smaller and faint.

Population structure, threats and conservation status:— Stachys virgata was first assessed as Rare (R), based solely on the historical information of old locations in Akrokorinthos, Kranidi, Trizina and Methana ( IUCN 1982, Walter & Gillett 1998). These populations have not been confirmed in recent years, but 18 new populations were discovered in east Peloponnisos between 2005 and 2014 ( Table 1). Population no.10, consisting of 10 plants and located in private land, was destroyed between 2005 and 2011 following dramatic changes of its surrounding vegetation, extensive herbicide use and a building construction in its habitat. Twelve out of the 18 known populations harbour a very small number of plants (20 mature individuals or less) and only 4 of the known populations exceed 30 individuals, with population no. 17 being the largest with 102 individuals. Most recent fieldwork estimated a total population of 355 mature plants. The species’ extent of occurrence (EOO) does not exceed 100 km 2 and since S. virgata is a very local species, its area of occupancy (AOO) is much narrower, apparently less than 10 km 2. The main threats Stachys virgata is facing are mostly associated with land use changes and human interference and less with the development of thick maquis formations in the species’ habitats. Population no. 12 was observed under retreat in both plant number and AOO, due to herbicide applications between 2011 and 2013. The uncontrolled herbicide use could affect 6 additional populations. Fires lit on purpose, usually aiming at controlling undesirable vegetation in olive groves and private land, also pose a serious threat to the species (particularly in pop. nos. 10, 11, 15). Changes or abandonment of traditional agriculture activities enable a thickening of maquis vegetation leaving thus no suitable niches for S. virgata in at least three localities. Road construction works may affect 9 populations. Finally, settlement construction activities and vegetation clearance pose less imminent threats to Stachys virgata , since they affect 4 populations. Mild human influence, on the other hand, such as the one traditionally expressed in many Peloponnesian villages (olive tree cultivation, avoidance of plugging and herbicides use, moderate grazing that controls the maquis development, maintaining dirt roads and paths) may have a positive impact on the S. virgata populations. Due to: i) the restricted EOO and AOO (less than 100 km 2 and 10 km 2, respectively), ii) the current existence of 355 mature individuals distributed in 18 small populations, iii) the apparent extinction of all historical populations, and iv) the high possibility that the extant species’ localities and populations could be eradicated either as the result of human interference or by stochastic events, Stachys virgata is assigned to the Endangered (EN) IUCN (2001) category, following criteria B1ac(i,ii,iii,iv)+2ac(i,ii,iii,iv). Hence, S. virgata should be carefully monitored, cultivated ex situ in botanical gardens and special conservation measures be taken to safeguard at least the larger known populations. Further conservation suggestions for each separate population are described in Table 1.

Taxonomic position:— Bhattacharjee (1980) placed Stachys virgata in S. sect. Olisia Dumortier (1827: 44) subsect. Rectae Bhattacharjee (1980: 85) , together with five additional Greek species: S. angustifolia Marschall von Bieberstein (1808: 52) , S. atherocalyx Koch (1849: 691) , S. leucoglossa Grisebach (1844: 140) , S. tetragona Boiss. & Heldr. in Boissier (1879: 736) and S. recta . A sixth species, S. iberica Marschall von Bieberstein (1808: 51) was reported by Halácsy (1902: 525, Mt. Oeta, also known as Mt. Iti) and accepted by Bhattacharjee (1982: 244) as a member of the Greek flora, but its existence has never since been verified or documented. Stachys virgata produces long inflorescences predominately composed of 2-flowered verticillasters and resembles, in this respect, S. angustifolia and S. tetragona . The former differs by its glabrescent stems, linear pinnatipartite middle and lower cauline leaves and longer pedicels (2–5 mm vs. 0–2 mm) on at least the lower verticillasters. The later differs by its shorter habit, glabrous or sparse patent hairy upper stem parts and calyx and lack of a dense tuft of protruding hairs on the calyx throat. Furthermore, S. tetragona is a chasmophyte with a particular preference for limestone rocks, cliffs and scree ( Persson 1981), in contrast to the maquis and man-influenced habitats preferred by S. virgata . The rest of Greek Stachys subsect. Rectae members present denser verticillasters consisting of 3–16(–18) flowers and are presumably more distantly related to S. virgata . A key to all Greek species of S. subsect. Rectae (plus S. iberica subsp. iberica ) is provided below.

Figures

FIGURE 3. Total known distribution of Stachys virgata. Red circles indicate historical sites not confirmed the last 171 years. Yellow circles refer to the new populations discovered between 2005 and 2014.

FIGURE 4. A metaphase plate of Stachys virgata with the diploid chromosome number of 2n = 34 on material near Krioneri settlement (population no. 16—see Appendix for details).