Ferula sommieriana Cambria, C. Brullo, Tavilla, Sciandr., Minissale, Giusso & Brullo, 2021

Cambria, Salvatore, Brullo, Cristian, Tavilla, Gianmarco, Sciandrello, Saverio, Minissale, Pietro, Galdo, Gianpietro Giusso Del & Brullo, Salvatore, 2021, Ferula sommieriana (Apiaceae), a new species from Pelagie Islands (Sicily), Phytotaxa 525 (2), pp. 89-108 : 90-102

Ferula sommieriana Cambria, C. Brullo, Tavilla, Sciandr., Minissale, Giusso & Brullo sp. nov. ( Figs.1 , 2 , 3A , 5 )

– F. communis auct. fl. pelagie, non Linnaeus (1753: 246) .

A Ferula communis L. scapo umile, diametro minore, foliis lucidis, hispidulo–scaberrimis, denticulatis margine, segmentis terminalibus multo brevioribus usque ad 5 mm longis, petalis brevioribus, stylopodio minore, stylo breviore, ovario minore, mericarpio rotundato vel rotundato-oblongo, vittis 2–3 per valleculas, vittis commisuralibus 4–6, lamina cotiledonum angustiore differt.

Type:— SICILY. Lampedusa Island , Contr. Sanguedolce, 15 March 2021, S . Cambria s.n. (holotype: CAT!) .

Perennial polycarpic herb; rootstocks well developed; stem solitary, glabrous, stout, erect, 50–120 cm tall, 0.5–3 cm in diameter, terete, finely striate, at nodes slightly dilated; internodes 8–10(12); lower branches alternate, upper ones verticillate. Basal leaves green, shining, petiolate, abruptly broadened into sheaths lanceolate, papery, amplexicaul, rigid, inflated, sulcate, up to 18 cm long; leaf blades more or less triangular in outline, 18–50 cm long, 8–35 cm wide, 5–6-pinnate, scabrous-hispidulous; terminal segments, 0.5–5 mm long, 0.5–1 mm wide, linear, acute to slightly obtuse, mucronate, denticulate at the margin; lowermost cauline leaves similar to basal ones, but with sessile blade; middle and uppermost leaves progressively reduced to a conspicuous sheath without blade. Inflorescence paniculate-corymbose, provided with umbels lacking bracts; hermaphrodite central umbel with peduncle 3–25 mm long (rarely subsessile, rays 10–30, terete, 15–40 mm long, subequalling, a little divaricate; hermaphrodite umbellets with 8–20 flowers and rays 5–8 mm long, bracteoles 0–3, 1– 2 mm long; staminate lateral umbels 2–3, smaller, with 10–25 flowers and rays 5–24 mm long; staminate umbellets with 8–16 flowers and rays 1.5–2.5 mm long, with 4–6 bracteoles, 0.8– 2 mm long. Calyx teeth inconspicuous, 0.3–0.4 mm long. Petals yellow, ovate, subentire, with narrow tip curved inwards; hermaphrodite ones 1.6–2.3 mm long, staminate ones 1.3–1.7 mm long. Stamens yellow, with filament up to 2.5 mm long, anther ca. 1 mm long. Stylopodium yellow, saucer-shaped, bilobed, in hermaphrodite flowers 1.9–2.1 mm in diameter, in staminate ones 1.2–1.3 mm in diameter; styles in the staminate flowers inconspicuous, in the hermaphrodite ones erect, 0.6–0.9 mm long; ovary 1–1.2 mm long. Fruit dorsally compressed, brown; carpophore bifid up to the base; mericarps orbicular to orbicular-oblong, 9–16 mm long, 8–14 mm wide; dorsal ribs 3, filiform; lateral wings 1–1.6 mm wide; big vascular bundles in every dorsal rib and some thin in lateral wings; dorsal vittae 2–3 per vallecula, commissural secretory ducts 4–6.

Phenology:—It flowers in February–April, and fruits in May–June.

Etymology:—The new species is named in honour of Stefano Sommier (1848-1922), botanist from Florence, for his valuable contribution to the flora of the Pelagie Islands.

Distribution and habitat:— Ferula sommieriana exclusively grows at Lampedusa and Linosa, islands of Pelagie Archipelago in the Channel of Sicily, where it was misidentified with F. nodosa or F. communis ( Gussone 1843, Sommier 1906, Di Martino 1961, Bartolo et al. 1990, Brullo & Siracusa 1996a). It usually grows in stands quite far from the sea, mainly in the uncultivated fields and synanthropic habitats characterized by the occurrence of thermoxerophilous perennial vegetation ( Figs. 4 , 5 ). This species is uncommon at Lampedusa, localizing in few stands, where, according to Bartolo et al. (1990) and Brullo et al. (2010), it is linked to a calcicolous plant community dominated by Asphodelus ramosus Linnaeus (1753: 310) , Charybdis pancration ( Steinheil, 1836: 279) Speta (1998: 60) , Foeniculum vulgare Miller (1768 s.p.), Euphorbia pinea Linnaeus (1767: 333) , Cynara cardunculus Linnaeus (1753: 827) , Phagnalon saxatile (Linneaus, 1753: 857) Cassini (1819: 174) , Dactylis hispanica Roth (1797: 8) , Convolvulus althaeoides Linnaeus (1753: 156) , Pallenis spinosa (Linneaus, 1753: 904) Cassini (1825: 276) , Carlina involucrata Poiret (1789: 234) and sometimes it is also associated with the endemic Thapsia pelagica Brullo et al. (2009: 46) . Conversely, F. sommieriana from Linosa is quoted by Brullo & Siracusa (1996b) and Brullo et al. (2010) on volcanic soils, but in xeric grasslands dominated by Hyparrhenia hirta (Linneaus, 1753: 1046) Stapf (1919:315) and characterized by Lathyrus articulatus Linnaeus (1753: 731) , Daucus carota Linnaeus (1753: 242) , Foeniculum piperitum , Euphorbia pinea , Phagnalon saxatile , Charybdis pancration , etc. Probably, the garrigues and maquis enviroments that are now quite rare and limited to small patches on both islands, were most likely the natural habitats colonized in the past by F. sommieriana .

Phytogeographical remarks:—The Pelagie Islands are included by Brullo et al. (1995) in the Pelagico Domain together with Pantelleria island and Maltese Archipelago. Within this domain several districts were recognized, among which the Lopadusano district with Lampedusa and Lampione islands, and Algusico district with Linosa Island. The aforesaid districts show a remarkable lot of endemic species which confer them a certain phytogeographic isolation. In particular, the flora of Lampedusa is quite rich in endemics, such as Allium hemisphaericum ( Sommier, 1906: 147) Brullo in Bartolo et al. (1990: 131), A. lopadusanum Bartolo et al. (1986: 89) , A. pelagicum Brullo et al. (2015: 235) , Anthemis lopadusana Lojacono (1903: 85) , Chiliadenus lopadusanus Brullo (1979a: 301) , Daucus lopadusanus Tineo (1846: 38) , Dianthus rupicola Bivona (1806: 31) subsp. lopadusanus Brullo & Minissale (2002: 541) , Diplotaxis scaposa Candolle de (1821: 635), Limonium intermedium Gussone (1832: 87) Brullo (1980: 283) , L. lopadusanum Brullo (1980: 281) , Oncostema dimartinoi ( Brullo & Pavone, 1987: 614) Conti & Soldano in Conti et al. (2005: 20), Suaeda pelagica Bartolo et al. (1987: 391) and Thapsia pelagica . As concerns Linosa, the flora of this island is less rich in endemics, they are: Erodium neuradifolium Delile ex Godron (1853: 17) subsp. linosae ( Sommier, 1906: 205) C. Brullo et al. (2011: 37) , Limonium algusae ( Brullo, 1980: 289) Greuter (1987: 449) and Valantia calva Brullo (1979b:61) .

Seedling morphology:—The seedling morphology in the Apiaceae provides relevant informations on the taxonomic relationships at generic and specific rank ( Cerceau-Larrival 1962; Das 2017). Previously, the seedling of Ferula species were studied by Cerceau-Larrival (1962), who examined those ones of F. communis , while Brullo et al. (2018) treated F. communis , F. melitensis and F. arrigonii highlighting the morphological differences. Based on these investigations, the seedlings of F. sommieriana ( Fig. 6 A-B) differs from that one of F. communis ( Fig. 6C ) in having cotyledons max 9 cm long and blade 1.8–2.5 mm wide (versus up to 14 mm long and 3.5–5 mm wide), metaphyll blade 3–5 × 3.5–5.5 mm (versus 4.5–8 × 4.5–8 mm), metaphyll petiole longer, rarely subequal, than cotyledons (versus shorter than cotyledons). The seedlings of F. sommieriana differ very well also from that one of F. melitensis ( Fig. 6D ) in having cotyledons 7–9 mm long and blade 1.8–2.5 mm wide (versus 9–11 mm long and blade 3.5–4 mm wide), metaphyll petiole longer, rarely subequal, than cotyledons (versus subequal to shorter), metaphyll blade with segments 0.5–1 mm wide (versus 1–1.5 wide). Finally, some significant differences there are between the seedlings of F. sommieriana and that one of F. arrigonii . In particular, F. sommieriana shows seedlings much larger with cotyledons 7–9 mm long (versus 4.5–5.5 mm long), metaphylls 9–16 mm long (versus 6.5–8 mm long), with blade 3–5 mm long (versus 2.3 mm long) and petiole 6.5–11 mm long (versus 5–6.5 mm long), longer, rarely subequal, than cotyledons (versus shorter), metaphyll blade with segments 2–11 × 0.5–1 mm (versus 2.5 × 1.5–2 mm).

Mericarp morphology:—According to literature ( Cauwet-Marc 1981a,b; Safina & Pimenov 1983, 1990; Arenas Posada & García Martín 1993; Duman & Sağıroğlu 2005; Sağıroğlu & Duman 2007, 2010; Pimenov & Kljuykov 2013; Brullo et al. 2018; Akalın et al. 2020) the carpological investigations provide relevant information on the taxonomy of the genus Ferula . The two mericarps compressed dorso-ventrally, with a wing per side, are characterized by a dorsal and a commissural face, with 3 thin dorsal ribs, each with a vascular bundle, secretory ducts occur in the vallecoles interposed between the ribs and in the commissural faces. As concerns the mericarps of F. sommieriana , they are rounded to rounded-oblong, showing a quite variable size with a range of 9–16 × 8–14 mm, provided with a wing 1.5–2.5(3) mm wide ( Fig. 3A ); the secretory ducts are 2–3 per vallecula, while the commissural ones are 4–6 ( Fig. 7A ). On the whole, based on our investigations and literature data, the mericarps of F. sommieriana result well differentiated from those ones of the allied species known in literature such as F. communis s.str., F. glauca . F. tunetana , F. arrigonii and F. melitensis . The mericarps of F. communis s. str. are obovate to elliptical, (10)12–18(20) × 7–12 mm, with wings 2–3 mm wide, secretory ducts 1–3 per vallecula, and commissural secretory ducts 2–4 ( Fig. 3B , Fig. 7B ; Safina & Pimenov 1990, Fig. 1 ). In F. glauca the mericarps are elliptical, 13–20 × 7–12 mm, with wings 1.0– 1.5 mm wide, secretory ducts 2–4 per vallecula, and commissural secretory ducts 4–6 ( Safina & Pimenov 1990, Fig. 3B ). The mericarps of F. tunetana are orbicular to elliptical, 12–18 × 12–14 mm, with wings 2.5 mm wide, secretory ducts 3 per vallecula, and commissural secretory ducts 4 ( Bonnet & Barratte 1895: pl. 8). The mericarps of F. arrigonii are oblong to ovate-oblong, (5)7–10 × 3–6 mm, with wings 0.5–1.0 mm wide, secretory ducts 1–3 per vallecula, and commissural secretory ducts 4(6) ( Brullo et al. 2018, Fig. 3C and 4C ). Finally, F. melitensis shows orbicular to orbicular-oblong mericarps, 11–14 × 9–11 mm, with wings 1.5–2.0 mm wide, secretory ducts 1–4 per vallecula, and commissural secretory ducts 4–7 ( Fig. 3C , Fig. 7C ; Brullo et al. 2018, Fig. 3A and 4A ).

Leaf anatomy:—The leaf blade in Ferula shows usually a remarkable diacritical value for the taxonomic differentiation of the species among them. In fact, most often a very flashy character which allows to easily distinguish one species from another is the leaf morphology and it is widely used in the drafting of keys in the floras ( Cannon 1968; Peşmen 1972; Sànchez Cuxart 2003). Besides, the anatomical investigations on the leaf blade can provide further information to improve knowledge in the case of critical groups or in the description of new species ( Ashena et al. 2014; Akhemetova et al. 2015; Imanbayeva et al. 2015; Brullo et al. 2018). Morphologically, Ferula sommieriana for its leaf blade is clearly differentiated from the other allied species belonging to F. communis group. In fact, the terminal segments of the leaf blade are very short (max 5 mm long), minutely scabrous-hispidulous on both faces ( Fig. 8C, D ). As concerns the others examined species as F. communis ( Fig. 8A ) and F. melitensis ( Fig. 8B ), as well as F. glauca , F. arrigonii , the terminal segments can reach a length far greater than 5 mm and have the surface perfectly smooth. A certain similarity in the size of the terminal segments was observed between the leaves of F. sommieriana and F. tunetana , but they differ in some features, since the terminal segments in F. tunetana are smooth and slightly larger (1-2 mm wide), even if in length they do not exceed 2 mm. Investigations on the anatomy of the terminal leaf segments in F. sommieriana showed much greater differences compared to those of the other related species of Ferula . In the cross section the leaflets reveal a flat outline rounded at the ends, rounded abaxially and furrowed adaxially ( Fig. 2E ). The tissues have an amphistomatic dorsiventral arrangement, with a cuticle with cells larger in the adaxial face, where the stomata are few in number, with large substomatal chambers in the abaxial face, placed on both sides of the midrib; all the surface is covered by scattered minute protuberance, that give a some roughness. The palisade tissue is two-layered, with cells diversified on the two faces; in the adaxial face the cells in cross section are elongated with those of the outer layer longer and those of the inner one much shorter; while the palisade tissue in the abaxial faces is characterized by smaller and rounded cells; the palisade is interrupted by small collenchymatic cells bundle above and below the midrib. The spongy tissue fills the central part of the leaflets and consists of small rounded compact cells, where three vascular bundles are located, a biggest central one and two smaller marginal ones, each one is associated with a secretory duct of proportional size located towards the abaxial face; the whole structures are surrounded by a layer of mechanical cells and enclosed by an external well-developed collenchyma. In the cross section the central segment of the leaflets is characterized by a palisade tissue multilayered with 6–7 vascular bundle and a very deep furrow in adaxial face ( Fig. 2F ).

Based on investigations carried out by Brullo et al. (2018), the terminal leaf segments of F. sommieriana in cross section result quite similar to that one of Ferula communis . The two species share the same width of the terminal segments, as well as they have three vascular bundles, palisade tissue interrupted by small collenchymatic cells on both faces, while they differ for the occurrence in F. communis of palisade cells elongated and larger in the abaxial face; besides the leaflets surface is completely smooth ( Brullo et al. 2018, Fig. 6D ). The leaflets in cross section of others investigated species ( F. arrigonii , F. melitensis , F. tunetana ) are more differentiated compared to F. sommieriana mainly for the occurrence usually of a greater number of vascular bundles (1–2 intermediate bundles), epidermal cells larger, as well as but limitedly to F. melitensis and F. tunetana , the lack of furrow and collenchymatic bundles in the adaxial face ( Brullo et al. 2018, Fig. 6A, B, C ). Unfortunately, due to the lack of living material, it was not possible to carry out analyzes on the anatomy of the leaves of F. glauca , a species quite related to F. communis , but based on literature data ( Cannon 1968; Anzalone et al. 1992) it differs morphologically from F. sommieriana in having terminal segments of leaflets longer and wider (5–30 × 1–3 mm), which are distinctly green above and glaucous below.

Figures

FIGURE 1. Flowers of Ferula sommieriana. A) Male umbellets; B) Bracteoles in male umbellets; C1) Hermaphrodite flowers above vision; C2) Male flowers above vision; D 1) Hermaphrodite flower lateral vision; D 2) Male flower lateral vision; E 1) Petals of hermaphrodite flower;E 2) Petals of male flower;F 1) Gynostemium in hermaphrodite flower; F 2) Gynostemium in male flower;G1) Calyx inhermaphrodite flower; G2) Calyx in male flower; H 1) Anther in hermaphrodite flower; H 2) Anther in male flower. Illustration by S. Brullo based on living material coming from Lampedusa (Sicily).

FIGURE 2. Leaves of F. sommieriana. A) Terminal parts of leaf blade from Lampedusa; B) Terminal part of leaf blade from Linosa; C) Details of terminal part of leaf blade from Lampedusa (low magnification); D) Details of terminal part of leaf blade from Lampedusa (high magnification); E) Cross sections of terminal leaflet segments from Lampedusa; F) Cross section of central segments leaflet from Lampedusa. Illustration by S. Brullo based on living material coming from Lampedusa and Linosa (Sicily).

FIGURE 3. Mericarps of Ferula sommieriana (A), F. communis (B) and F. melitensis (C). 1) Dorsal face; 2) Commisural face. Illustration by S. Brullo based on living material coming from Lampedusa (A), Sicily (B) and Malta (C).

FIGURE 4. Geographical distribution of Ferula sommieriana (red dot), F. melitensis (blue dot), F. tunetana (green dot) and F. communis (yellow area) based on herbarium materials and literature data.

FIGURE 5. Ferula sommieriana from Lampedusa A. Habit. B. Leaf. C. Detail of terminal leaf blade. D. Cauline leaf. E. Inflorescence. (Photo by S. Cambria).

FIGURE 6. Seedlings. A) F. sommieriana from Lampedusa; B) F. sommieriana from Linosa; C) F. communis from Sicily; D) F. melitensis from Malta. Illustration by S. Brullo based on living material.

FIGURE 7. Mericarp cross section of Ferula sommieriana (A), F. communis (B) and F. melitensis (C). Illustration by S. Brullo based on living material coming from Lampedusa (A), Sicily (B) and Malta (C).

FIGURE 8. Outline of the terminal leaflet blade. A) Ferula communis from Sicily; B) F. melitensis from Malta; C) F. sommieriana from Lampedusa; D) F. sommieriana from Linosa. Illustrations by S. Brullo based on living material.