Kali basalticum C. Brullo, Brullo, Gaskin, Giusso, Hrusa & Salmeri, 2015

Brullo, Cristian, Brullo, Salvatore, Gaskin, John F., Galdo, Gianpietro Giusso Del, Hrusa, G. Frederic & Salmeri, Cristina, 2015, A new species of Kali (Salsoloideae, Chenopodiaceae) from Sicily, supported by molecular analysis, Phytotaxa 201 (4), pp. 256-277 : 259-269

Kali basalticum C. Brullo, Brullo, Gaskin, Giusso, Hrusa & Salmeri , sp. nov. ( Figs. 1–2 )

Type:― ITALY. Sicily: Monte Etna, versante nord-occidentale in contrada Rocca Tufano, c. 7 km a sud di Bronte, su substrato lavico, 750 m, 3 October 2010, S. Brullo & G. Giusso del Galdo s.n. (holotype CAT!).

Diagnosis: ― Kali australi simili sed scapi ramis ascendentibus, foliis 0,5– 1 mm latis, bracteorum axilla glabra, bracteis usque ad 20 mm longis, bracteolis 5–8 mm longis, spina apicali 1–2 mm longa, tepalis 0,9–2,1mm longis, staminorum filamentis 4,5– 5 mm longis, antheris 1,5–1,8 mm longis, utriculo a fructifero perianthio tecto, parte distali tepalorum fructiferorum conum erectum formantibus, alis minoribus flabellatis.

Description: ―Annual herb, 10–50 cm tall. Stems erect, branched from base, green, glabrous or nearly so, with longitudinal whitish striae. Leaves flexuous, soft, linear-subcylindrical (15–45 × 0.5–1 mm), glabrous or subglabrous, basally expanded, margin membranaceous-hispid at base, apical spine up to 1 mm long. Inflorescence spike-like; bracts linear-lanceolate to ovate-lanceolate (6.0–20 × 2.2–3.2 mm), longer than bractlets, margin widely membranaceous in the lower part, irregularly denticulate, 3-nerved, apical spine 1–1.5 mm long; bractlets ovate-lanceolate (5.0–8.0 × 2.0– 2.5 mm), bracts-like in shape, but shorter. Tepals hyaline, greenish below, oblanceolate (2.5–3.2 × 1.5–2.1 mm), rounded, irregularly denticulate above. Staminal filaments hyaline, 4.5–5.0 mm long, fused at the base in a thin annulus, alternating to semicircular staminodes hispid at apex; anthers yellow, 1.5–1.8 mm long. Ovary ovoid, about 0.5 mm long; style 0.5–0.6 mm long; stigma bifid, about 2.5 mm long. Fruiting perianth 4.5–6.0 mm in diameter, with 5 segments winged, coriaceous, membranaceous, with different shape and size; two of them larger (3.0– 4.5 mm wide), one smaller (2–3 mm wide) and two very small (0.7–1.5 mm wide), fan-shaped; distal part of the segments gradually narrowed in a triangular apex, forming a weak conical beak above the broad wings. Utricle membranaceous, sub-obconic (1.5–1.7 × 2.0– 2.1 mm). Seeds horizontal obconic (about 1 mm in diameter), with a spiral embryo.

Etymology: ―From latin “ basalticus ”, viz occurring on basaltic rocks, where the species grows.

Phenology: ―Flowering in autumn (september–october). Fruits begin to ripen until the middle of the flowering period starting from the lower flowers. Dried plants do not come off the ground and the fruiting perianth remains attached to the bracts for a long time after drying.

Habitat and distribution: ― Kali basalticum grows on basaltic lava flows on the north-western slope of Mt. Etna (eastern Sicily). It occupies an area of about 5 km 2 at an elevation of 700–900 m a.s.l. The plant mainly occurs in sub-nitrophilous stands, such as road sides, uncultivated lands, rocky outcrops, where it grows together with other rare Sicilian endemics chiefly occurring in the Etnean district, such as Heliotropium bocconei Gussone (1825: 6) , Crassula basaltica Brullo & Siracusa (1994: 175) , Celtis aetnensis ( Tornabene 1855: 195) Strobl (1881: 397) , and Silene vulgaris ( Moench 1794: 709) Garcke (1869: 64) subsp. aetnensis ( Strobl 1885: 362) Pignatti (1973: 208) .

Conservation status: ― Kali basalticum is currently known only from the type locality, where it is represented by a single population of about 1000 individuals. Over many years of observation, it was determined that the number of flowering individuals varies by about 5–10%, depending on rainfall. According to IUCN Red list category ( IUCN 2014), this species for its rarity and punctiform distribution (4–5 ha) can be considered as Critically Endangered: CR B2ac(iii, iv).

Karyology and genotype: ―According to literature, the basic chromosome number in the Chenopodiaceae is usually x=9, with few exceptions such as Cremnophyton lanfrancoi Brullo & Pavone (1987: 622) with x=10. Furthermore, all the Kali species karyologically studied so far have this basic number ( Kockx van Roon & Wieffering 1982, Nishikawa 1985, Lago Canzobre 1989, Bailey 1992, Lomonosova & Krasnikov 1993, Khatoon & Ali 1993, Lövkvist & Hultgård 1999, Lomonosova et al. 2001, Lomonosova et al. 2003, Lomonosova 2005, Probatova 2005, Toderich et al. 2006, Probatova et al. 2009, Ayres et al. 2009). Within the genus Kali , some species are diploid with 2n=18 (e.g., K. australe , K. collinum , K. griffithii , K. monopterum , and K. ponticum ), others are tetraploid with 2n=36 (e.g., K. komarovii , K. paulsenii , K. praecox , K. tragus and K. turgidum ), and only one is hexaploid with 2n=54 ( K. ryanii ). Also K. basalticum is characterized by a chromosome complement of 2n=54 ( Fig. 3 ), thus differing from almost all the other species of the genus. Concerning K. ryanii , it was described from California by Hrusa & Gaskin (2008), and considered by the authors as a natural hybrid between the introduced K. tragus (2n=36) and K. australe (2n=18), with both parental taxa occurring in the distribution range of this nothospecies. It is interesting to note that K. ryanii has two (1/4 or 2/3) or sometimes three (2/4/5) different haplotypes from its two parents ( Fig. 4 ), homozygous or heterozygous 4n and 2n ( Hrusa & Gaskin 2008), while K. basalticum was a haplotype 3 (assumed to be a 3/3/3 genotype) for the PEPC DNA of K. ryanii and S. lax ( Hrusa & Gaskin 2008, Ayers et al. 2009, respectively). Kali basalticum was found to be genotype 3/3.

TABLE 2. Main morphological features of Kali basalticum and allied species.

sequence, which contains the same haplotype as K. australe samples analyzed in earlier studies ( Gaskin et al. 2006, Hrusa & Gaskin 2008, Ayers et al. 2009). Other than K. basalticum , K. australe , and K. ryanii , there are no other known Kali taxa that contain haplotype 3 or 4 ( Fig. 4 ). The parsimony analysis using nrDNA ITS sequences found three most parsimonious trees 485 steps in length with a consistency index of 0.72 and a homoplasy index of 0.27. Bootstrap values above 50% are shown on one of the three most parsimonious trees ( Fig. 5 ). In particular, K. basalticum falls within the genus Kali and is most closely aligned with K. tragus in all three most parsimonious trees (only one tree shown). Maximum likelihood analysis agrees with the placement of K. basalticum within Kali and most closely related to K. tragus ( Fig. 6 ), with 97% bootstrap value supporting that clade. In each analysis, the genus Kali was monophyletic with strong bootstrap support (97% and 99%, respectively).

Discussion: ―On the basis of the most recent taxonomic treatments regarding the species included in Salsola sect. Kali ( Rilke 1999, Mosyakin 2003, Zhu et al. 2003, Hrusa & Gaskin 2008, Ayers et al. 2009, Hrusa 2012), K. basalticum is clearly well different from the other taxa in several morphological features regarding the habit, indumentum, shape and size of the leaves, bracts, flowers, utricles, and fruiting perianth ( Figs. 7 , 8 , 9 ). In Table 2 are listed the most relevant characters of the Mediterranean Kali species (e.g., K. tragus , K. turgidum , and K. ponticum ), as well as of the allied K. australe , K. praecox , K. ryanii and K. paulsenii . In particular, K. australe seems to be morphologically more similar to K. basalticum , especially for the habit and leaf shape. Furthermore, K. australe , occurring in Australia and naturalized in North America and South Africa ( Hrusa & Gaskin 2008, Borger et al. 2008, Chinnock 2010), differs from K. basalticun in having indumentum minutely hispid, with hairs generally less than 1 mm long, leaves 2–3 mm wide, bracts max. 1 cm long, woolly at the axil and spine 0.5–1.0 mm long, bracteoles 0.4–0.8 mm long, tepals oblong-ovate, 0.7–0.8 mm wide, acute and smooth at the apex, stamen filament 2.0– 2.5 mm long, anther 0.45–0.70 mm long, stigma 1.2–1.4 mm long, fruiting tepals not covering the utricle, with apex soft, not conic, the two smaller inner wings obovate-spathulate, 1.5–2.0 mm wide, utricle 1 mm long, fructiferous perianth detached after drying. Besides, K. basalticum also differs from other species of the Mediterranean Kali ( K. tragus , K. turgidum and K. ponticum ) in having the habit delicate, flexuous, leaves slender and soft, bract and bracteole linear-lanceolate to ovate-lanceolate, tepals 1.5–2.1 mm wide, stamen filament 4.5–5.0 mm long, anther 1.5–1.8 mm long, winged fruit developing from the middle of flowering season. In contrast, the Mediterranean species are characterized by a robust habit, rigid stems, leaves thick and rigid, bracts and bracteoles ovate to ovate-triangular, tepals 0.8–1.6 mm wide, stamen filaments 3.0– 3.7 mm long, anthers 0.6–1.6 mm long, winged fruits developing at the end of flowering season. Moreover, they usually grow on coastal sandy habitats, where they find optimal conditions along the shoreline. In fact, these Kali species, being psammophytes with an halo-nitrophilous needs, are restricted to stands covered by organic matter and directly affected by marine aerosol. Whereas, K. basalticum has completely different ecological requirements, since it grows on basaltic outcrops of inland sub-mountain stands, very far from the sea.

Additional specimens examined (paratypes): ― ITALY. Sicily, C. da Ruvolita (Bronte), 5 Ottobre 2010, S. Brullo & G. Giusso del Galdo s.n. (CAT, CDA).

Figures

FIGURE 1. Diagnostic features of Kali basalticum C. Brullo, Brullo, Gaskin, Giusso, Hrusa & Salmeri. A. habit. B. bracts. C. bracteoles. D. flower with bract and bracteoles. E. fruiting perianth. Illustration by S. Brullo based on living material coming from type locality (CAT).

FIGURE 2. Diagnostic features of Kali basalticum C. Brullo, Brullo, Gaskin, Giusso, Hrusa & Salmeri. A. flower. B. open perianth with stamens. C. staminodes. D. anther. E. pistil. F. fruiting perianth. G. utricle (lateral view). H. utricle (above view). I. embryo (above view). J. embryo (below view). K. embryo (lateral view). Illustration by S. Brullo based on living material coming from type locality (CAT).

FIGURE 3. Chromosome complement (2n = 54) of Kali basalticum. Mitotic metaphase plate from type locality.

FIGURE 4. Haplotype network of DNA sequences of the fourth intron of the PEPC gene region for Kali and Salsola species from the USA, Africa, and Eurasia (combined from Gaskin et al. 2006, Hrusa & Gaskin 2008, Ayers et al. 2009 and modified). Circles represent haplotypes recovered, and squares along lineages in between circles indicate haplotypes not recovered. Each link between haplotypes indicates one mutational event. Angle of bifurcation and length of link between haplotypes have no significance. The loops that surround portions of the haplotype network indicate taxonomic status of plant collections sampled. Dotted lines indicate which haplotypes combine to form genotypes

FIGURE 5. Maximum parsimony tree of nrDNA ITS sequence data for Kali and Salsola species with 10,000 fast stepwise-addition bootstrap analysis. Bootstrap values are shown above branches. Genera are listed to the right of the species names (asterisk indicates provisional generic name as proposed by Akhani et al., 2007).

FIGURE 6. Maximum likelihood tree of nrDNA ITS sequence data for Kali and Salsola species using the nucleotide substitution model of K2+G and 1000 bootstrap repetitions. Bootstrap values are shown above branches. Genera are listed to the right of the species names (asterisk indicates provisional generic name as proposed by Akhani et al., 2007).

FIGURE 7. Open perianth with stamens (1), flower (2), and utricle (3) of A. Kali basalticum, B. K. australe, C. K. turgidum, D. K. tragus and E. K. ponticum. Illustration by S. Brullo.

FIGURE 8. Fruiting perianth of A. Kali basalticum, B. K. turgidum, C. K. paulsenii, D. K. australe, E. K. tragus, F. K. praecox and G. K. ponticum. Illustration by S. Brullo.

FIGURE 9. Habit of Kali basalticum in natural stands (1), Vegetative branches from cultivated plants (2) of K. tragus (A), K. basalticum (B), K. turgidum (C), and K. australe (D). Fruiting branches from cultivated plants (3) of K. basalticum (A) and K. tragus (B).