Orobanche apuana Domina & Soldano, 2015

Domina, Gianniantonio & Soldano, Adriano, 2015, Orobanche apuana (Orobanchaceae) a new species endemic to Italy, Phytotaxa 207 (1), pp. 163-171 : 164-167

Orobanche apuana Domina & Soldano , spec. nov. ( Figs. 1 , 2 )

Type:— ITALY.Apuan Alps, Via Vandelli (Massa), 44°05’48”N, 10°13’09”E, 920 m a.s.l., dry pastures on carbonate lithosol, on Santolina pinnata Viv. , 13 July 2014, A. Soldano 16532 (holotype PAL!, isotypes FI!, Herb. Soldano!).

Plant 15–30 cm tall with stem slender and erect, reddish-brown or yellow-brown, densely glandular-pubescent, laxly scaled. Lower scales triangular to oval, sparsely glandular pubescent; upper scales linear-lanceolate and sparsely glandular-pubescent, brown, erect. Inflorescence short and lax with 10–25 flowers. Bracteoles absent. Floral bract reddish-brown or yellow-brown, glandular pubescent, acute, about as long as or slightly shorter than the corolla, deflexed in the distal part. Calyx segments entire or bifid, 8–12 mm long, with teeth shorter than the tube, the upper tooth longer than the lower one or subequal. Flowers erect-spreading at first, bent forward later, with few purple veins. Corolla 17–24 mm long, inflated above the insertion of the stamens. Dorsal line of the corolla slightly curved in the lower part, almost straight in the middle and strongly flexed forwards near the upper lip. Upper lip of the corolla almost entire or slightly emarginated in two crenate lobes, with glandular hairs. Lower lip of the corolla with three, equal, crenate, deflexed lobes. Stamen inserted 3–5 mm above the base of the corolla, with filaments pubescent at the base. Anthers pubescent in the line of fusion. Style glandular-pubescent; stigma yellow, bilobate.

Host:— Orobanche apuana is exclusively parasitic on the Apuan Alps endemic Santolina pinnata Viviani (1802: 31) ( Asteraceae ). The latter name, although dismissed by Garbari & Bechi (1992) and Peruzzi et al. (2014, 2015), is correct, because its alleged earlier homonym S. pinnata Donn (1800: 107) is not validly published (see, in particular, Art. 38.2 Ex. 3 of the ICN, McNeill et al. 2012).

Flowering time:—Flowering and fruiting from late June, at lower altitudes, to early August in the higher ones.

Ecology and Distribution:— Orobanche apuana was collected on the Apuan Alps, on the western slopes of Monte Tambura from 600 to 1200 m a.s.l. on sunny carbonate rocks and dry pastures on lithosol. A photo of this plant from Campocecina (Massa-Carrara), at 1250 m, the 11.07.2010, by Melania Marchi was seen also on the forum of Acta Plantarum (http://www.actaplantarum.org/floraitaliae/viewtopic.php?f=40&t=19583&p=133289&hilit=orobanche+c ampocecina#p133289). It is it plausible that O. apuana grows also in other localities of the Apuan Alps where its host, S. pinnata occurs locally abundant from 500 to 1500 m on pioneer thermo-xerophilous formations of cliffs with open woods. This vegetation hosts a rich component of taxa endemic to Central and Northern Italy ( Ansaldi & Maccioni 2006), as Moltkia suffruticosa ( Linnaeus 1763: 1667) Brand (1902: 1999) subsp. bigazziana Peruzzi & Soldano (2010: 385) , Buphthalmum salicifolium Linnaeus (1753: 904) subsp. flexile ( Bertoloni 1854: 413) Garbari (1971: 191) , Leontodon anomalus Ball (1850: 9) , Silene pichiana Ferrarini & Cecchi (2001: 246) , Rhamnus glaucophylla Sommier (1894: 19) .

Further specimens seen (paratype):— ITALY. Via Vandelli (Massa), 44°05’48”N, 10°13’09”E, 920 m a.s.l., on Santolina pinnata Viv. , July 1996, A. Soldano (Herb. Soldano!).

Taxonomic relationships:—By the curvature of the dorsal line of the corolla, bent, straight and humped near the apex, this species can be ascribed to the group of O. caryophyllacea Sm. (O. grex Galeatae G.Beck). Schneeweiss et al. (2004a) consider the character of the shape of the dorsal line of the corolla unstable and, on the basis of nuclear ITS sequences, demonstrated that this group is polyphyletic. In fact, in Italy, it includes O. caryophyllacea Smith (1798: 169) , O. lutea Baumgarten (1816: 215) and O. teucrii Holandre (1829: 322) that are morphologically close, but in the West part of the Mediterranean region also O. latisquama ( Schultz 1848: 104) Battandier (1890: 659) occurs, that is a quite different taxon ( Carlón et al. 2008). Orobanche apuana can be distinguished from the other species similar to O. caryophyllacea by the shape and the reduced size of the corolla, the shape of the calyx, the colour of the plant when dry and the shape of the floral bract ( Fig. 3 ). The diagnostic characters are summarized in Table 1. All these species are faithfully recurring on the same host plant or family: O. apuana only on Santolina pinnata ( Asteraceae ), O. caryophyllacea on Rubiaceae , O. lutea on Fabaceae , O latisquama and O. teucrii on Lamiaceae ( Rosmarinus and Teucrium respectively). In the western Mediterranean region, in the Iberian Peninsula, Balearic Islands and in the southwest of France O. santolinae Loscos & Pardo (1863: 79) occurs, parasitizing different species of Santolina at altitudes from 20 to 1900 m and flowering from May to August ( Pujadas-Salvà 2010). In Corse O. cyrnea Jeanmonod et al. (2005: 257) was recently described. These broomrapes share only the host genus ( Santolina ) with O. apuana but there is no close taxonomic relationship between them. In fact O. apuana has larger flowers with differentiated curvature of the dorsal line of the corolla and belongs to the group of O. caryophyllacea (O. grex Galeatae Beck 1930: 222), O. santolinae and O. cyrnea have smaller flowers with constant curvature of the dorsal line of the corolla, thus belonging to the group of O. minor Smith (1797: 422) (O. grex Minores Beck 1930: 167). Jeanmonod et al. (2005), on the basis of morphology and rbc L sequences analysis, consider difficult the assignment of O. cyrnea to one of the actually recognized group. On the forum Acta Plantarum (see above), the photos of O. apuana are identified as Orobanche elatior Sutton (1798: 178) . However, we are not able to find significant similarities with this species that, unlike O. apuana , has long, dense spike, dorsal line of the corolla with constant curvature, calyx segments bifid, rarely entire, lips of the corolla deeply emarginated the upper and deeply lobed the lower one.

*Character state observed in living plants.

Figures

FIGURE 1. Orobanche apuana: a) habit; b) floral bracts; c) calyx segments; d) frontal view of the corolla; e) flower; f) corolla in section; g) pistil; h) seeds (Drawings by G. Domina on the original material).

FIGURE 2. Orobanche apuana in the field on Santolina pinnata (Photo by M. Soldano).

FIGURE 3. Comparison of flowers: a) O. apuana, b) O. caryophyllacea, c) O. teucrii, d) O. lutea, e) O. latisquama, f) O. cyrnea, g) O. santolinae. (Drawings by G. Domina on the type materials).