Ferula melitensis Brullo, C. Brullo, Cambria, Giusso, Salmeri & Bacchetta, 2018

Brullo, Salvatore, Brullo, Cristian, Cambria, Salvatore, Galdo, Gianpietro Giusso Del, Salmeri, Cristina & Bacchetta, Gianluigi, 2018, A new species of Ferula (Apiaceae) from Malta, Phytotaxa 382 (1), pp. 74-88 : 75-83

publication ID	https://doi.org/ 10.11646/phytotaxa.382.1.3
persistent identifier	https://treatment.plazi.org/id/200F878A-0537-4455-FF34-4F2833E8F7FC
treatment provided by	Felipe
scientific name	Ferula melitensis Brullo, C. Brullo, Cambria, Giusso, Salmeri & Bacchetta
status	sp. nov.

Treatment

Ferula melitensis Brullo, C. Brullo, Cambria, Giusso, Salmeri & Bacchetta View in CoL sp. nov. ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 , 3A View FIGURE 3 , 4B View FIGURE 4 , 5A View FIGURE 5 , 6A View FIGURE 6 ,

7 View FIGURE 7 )

– F. communis View in CoL auct. fl. melit., non Linnaeus (1753: 246) View Cited Treatment

A Ferula communis View in CoL L. foliis lucentibus, segmentis terminalibus foliorum (1) 3–15 mm longis, 1,3–1, 5 mm latis; radiis umbellarum lateralium longioribus; petalis brevioribus; filamentis staminalibus et antheris brevioribus; stylopodio minore; mericarpio rotundato vel rotundato-oblongo, plerumque breviore, vittis commisuralibus 4–7 differt.

Type:— MALTA. Malta, White Rocks, 8 March 2014, S. Brullo s.n. (holotype: CAT!).

Perennial polycarpic herb, glabrous, stout, erect, 100–250 cm tall. Rootstocks 2–4 cm in diameter with collar covered by fibrous remains of withered leaves; stem solitary, 2–4 mm in diameter at the base, terete, finely striate, at nodes slightly dilated; internodes 8–11; lower branches alternate, upper ones verticillate. Basal leaves green, shining, petiolate, abruptly broadened into ovate-lanceolate sheaths, amplexicaul, coriaceous, inflated, sulcate, up to 40 cm long; leaf blades usually rhombic in outline, 20–50 cm long, 20–40 cm wide, 3–4-pinnatisect; terminal segments divaricate, (1) 3–15 mm long, 1.3–1.5 mm wide, linear, acute, apiculate; lowermost cauline leaves similar to basal ones, but with sessile blade; middle and uppermost leaves progressively reduced to a conspicuous sheath without blade. Inflorescence long branched in corymbose panicle, provided with umbels lacking bracts; hermaphroditic central umbel subsessile or shortly peduncled, rays 16–28, terete, 2–3 cm long, subequalling, a little divaricate; staminate lateral umbels 2–3(4), smaller, usually with 18 short rays, 1–2 cm long; umbellets with several bracteoles, 2–3 mm long. Calyx teeth inconspicuous. Petals yellow, ovate, 1.3–1.5 mm long, subentire without claw, with narrow tip curved inwards. Stamens yellow, with filament up to 2 mm long, anther ca. 1 mm long. Stylopod yellow, saucer-shaped, bilobed, ca. 2 mm in diameter; styles in the staminate flowers inconspicuous, in the hermaphrodite flowers erect, 0.8 mm long; ovary 1.8–2.0 mm long. Fruit dorsally compressed; carpophore bifid up to the base; mericarps orbicular to orbicular-oblong, 11–14 mm long, 9–11 mm wide; dorsal ribs 3, filiform; lateral wings 1.5–2.0 mm wide; big vascular bundles in every dorsal rib and some thin in lateral wings; secretory ducts 1–4 per vallecula, commissural secretory ducts 4–7.

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

Etymology:—The specific epithet ( melitensis , - e) refers to “ Melita”, the Latin name of Malta.

Distribution and habitat:— Ferula melitensis is very frequent in all the islands of the Maltese Archipelago, where it grows in different soils and habitats. Its primary stands are clearly represented by rocky places within garigues or maquis, locally rich in endemic and rare shrubs, where it is not, however, very common, being usually represented by isolated individuals. Instead, it finds its best expression in secondary habitats, such as xerophilous grasslands, often of synantropic origin (uncultivated fields), where it usually tends to constitute dense and large populations.

Seedling morphology:—According to Cerceau-Larrival (1962), the seedling traits have relevant implications in the taxonomy of the Apiaceae , mainly at generic and specific level. As concerns the genus Ferula , the seedlings are characterized by a not visible hypocotyl, which is only detected by serial anatomical covers, cotyledons extremely elongated, with long petioles connate at the base in a sheath, blade linear-lanceolate, usually with three parallel nerves, continuing in the petiole, and 1–2 marginal ones per side, metaphylls long petiolate, 2–3 pinnatisect, with segments linear and apiculate. In particular, the seedlings of F. melitensis are differentiated by cotyledons 9–11 cm long, with blade 3.5–4.0 mm wide, sheath 9–10 mm long, metaphylls 12.0– 14.5 cm long, blade triangular in outline, 2.8–4.2 × 3.5–6.5 cm, with segments 2–12 × 1.0– 1.5 mm, petiole 9–10 cm, subequal the cotyledons ( Fig. 5A View FIGURE 5 ). Instead, F. communis differs in having cotyledon 4–5 mm wide, sheath 5–6 mm long, metaphylls 10.0– 13.5 cm long, blade ovate in outline, 4.5–8.0 × 4.5–8 cm, with segments 5–25 × 0.5–1.0 mm, petiole 5–8 cm, shorter than the cotyledons ( Fig. 5B View FIGURE 5 ). In the case of F. arrigonii , the seedlings are much more differentiated by having cotyledons 4.5–5.5 cm long, with blade 2.5–3.0 mm wide, sheath 10–12 mm long, metaphylls 6.5–8.0 cm long, blade ovate-rounded in outline, 2–3 × 2–3 cm, with segments 2–5 × 1.5–2.0 mm, petiole 5.0– 6.5 cm, longer than the cotyledons ( Fig. 5C View FIGURE 5 ). These significant differences in the seedling morphology are a further support to their recognition at specific rank.

Mericarp morphology:—As emphasized by several authors ( Cauwet-Marc 1981a,b, Sáenz de Rivas et al. 1982, Safina & Pimenov 1983, 1990, Anzalone et al. 1992, Arenas Posada & García Martín 1993, Duman & Saðýroðlu 2005, Saðýroðlu & Duman 2007, 2010, Alkhatib 2010, Pimenov & Kljuykov 2013), the fruit morphology plays a very relevant taxonomical role in Ferula . The fruit is a typical cremocarp, consisting of two indehiscent one-seeded mericarps joined at the summit by a bifid filiform carpophore. The mericarps are usually very compressed dorsally, with 3 thin dorsal ribs, in correspondence of each one there is a vascular bundle, and two marginal wing-like ones, generally crossed by thinner vascular bundles. In order to verify the taxonomical relationships among Ferula melitensis and the allied species belonging to the F. communis group (namely F. communis s. str., F. arrigonii , F. tunetana and F. glauca ), their mericarps were investigated. In particular, 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. 3A View FIGURE 3 ); F. communis s. str. has mericarps 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 View FIGURE 3 ); F. arrigonii mericarps 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) ( Fig. 3C View FIGURE 3 ); F. tunetana has orbicular to elliptical mericarps, 12–18 × 12–14 mm, wings 2.5 mm wide, secretory ducts 3 per vallecula, and commissural secretory ducts 4 ( Bonnet & Barratte 1895: pl. 8); and F. glauca displays elliptical mericarps, 13–20 × 7–12 mm, wings 1.0– 1.5 mm wide, secretory ducts 2–3 per vallecula, and commissural secretory ducts 4(6) ( Safina & Pimenov 1990, Fig. 3B View FIGURE 3 ).

Leaf anatomy:—Anatomical investigations on the leaf blade provide additional information for a better characterization of species, mostly when they belong to groups taxonomically quite critical. Previous anatomical studies on Apiaceae ( Metcalfe & Chalk 1950, Van Wyk & Tilney 2011, Yýlmaz & Tekin 2013, Brullo et al. 2013, Akpulat & Ataşlar 2014) and in particular on the genus Ferula ( Ashena et al. 2014, Akhemetova et al. 2015) showed that there are still few data on this topic. Therefore, in order to improve the knowledge on the anatomical structure of leaves, investigations were carried out on Ferula melitensis and for comparison also on F. communis , F. arrigonii and F. tunetana . Our survey on the investigated species revealed that the more relevant morphological and anatomical differences mainly regard the terminal leaflet segments of the blade. In particular, F. melitensis is characterized by leaflet segments (1)3–15 × 1.3–1.5 mm, which in the cross sections reveal an almost flat outline, with rounded ends and midrib slightly protruding adaxially, without adaxial furrow; the tissues have a amphistomatic dorsiventral arrangement, the epidermic cells, covered by the cuticle, are smaller in the adaxial face, where the stomata are more numerous, with very large substomatal chambers, placed on both sides of the midrib, stomata in the adaxial face are scattered with inconspicuous substomatal chambers; the palisade tissue is two-layered, adaxially and laterally well developed with elongated cells, the outer ones bigger than the inner ones, while in the abaxial face it consists of small rounded cells interrupted by many large substomatal chambers; the spongi tissue filling the central part consists of small rounded cells, where five vascular bundles are located, a biggest central one, two medium-sized marginal ones and two smaller intermediate, each one 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 welldeveloped collenchyma, reaching the abaxial epidermis only in the central one ( Fig. 6A View FIGURE 6 ). Among the other Ferula species investigated, the leaf segment in cross section of F. melitensis shows closer relations with that of F. tunetana . In fact the two species share leaf segment rather flat, without adaxial furrow, epidermic cells smaller in the abaxial face, palisade tissue with bigger and uniform cells in the adaxial face, with small and rounded cells in the adaxial one, five vascular bundles and collenchymatic tissue of central bundle reaching only the abaxial epidermis. However, F. tunetana is differentiated by leaflet segments 1–2 × 1.0– 1.3 mm, fleshier and thicker, bigger epidermal cells, abaxial stomata with narrower substomatal chambers and bigger central secretory duct ( Fig. 6B View FIGURE 6 ). As concerns F. communis ( Fig. 6D View FIGURE 6 ) and F. arrigonii ( Fig. 6C View FIGURE 6 ), they differ markedly from the two previous species in having narrower leaflet segments, with midrib quite protruding abaxially, marked adaxial furrow, quite uniform epidermal cells, palisade tissue with smaller cells also occurring in the adaxial face, a much more developed collenchyma around the midrib, right down the epidermal layer of both surfaces. The two species however differ due to the number of vascular bundles, which are frequently three in F. arrigonii (one central and two marginal), with 1 or 2 occasional intermediate ones, but always only three in F. communis , as well as the two layered palisade tissue, that is quite uniform in F. arrigonii , while well differentiate in F. communis with longer cells in the outer layer. Moreover, F. communis is distinct from all the other investigated species in its thinner, slender and flexuous leaflet segments, 20–40(50) × 0.4–1.0 mm. Finally, F. glauca also shows some affinities with F. melitensis in relation to the leaflet segments quite flat and wide, but it clearly differs in having leaflet segments 5–30 × 1–3 mm, green above and distinctly glaucous beneath (cf. Cannon 1968, Anzalone et al. 1992).