Allium nazarenum subsp. ramonense C.Brullo, Brullo, Giusso & Salmeri, 2017

Brullo, Cristian, Brullo, Salvatore, Galdo, Gianpietro Giusso Del & Salmeri, Cristina, 2017, Allium nazarenum (Amaryllidaceae), a new species of the section Codonoprasum from Israel, Phytotaxa 327 (3), pp. 237-251 : 243-249

Allium nazarenum subsp. ramonense C.Brullo, Brullo, Giusso & Salmeri , subsp. nov. ( Fig.5 )

Type:— ISRAEL. Negev , Karnei Ramon, esemplare coltivato, June 1990, S. Brullo (holotype, CAT 059.183 !; isotypes, CAT!) .

A typo differt bulbo majore, scapo usque ad 55 cm longo, foliis 5–6, spathae valvis infloresentia plerumque brevioribus, valva majore 1.5–3.5 mm longa, 5–7-nervata, valva minore 1–2 mm longa, 3–5-nervata, inflorescentia usque ad 5 cm diametro, 40–110 floribus, pedicellis 8–20 mm longis, perigonio campanulato, tepalis truncatis vel apice rotundis, interioribus 1.8–2.2 mm latis, filamentis staminalibus exterioribus 1–1.2 mm longis, interioribus 1,4– 2 mm longis, antheris luteis, 1.2–1.3 mm longis, ovario ellipsoideo, 2.5–3 mm longo.

Description:—Bulb ovoid-subglobose, 12–18 × 10–15 mm, with coriaceous, blackish-brown outer tunics, the inner tunics membranaceous, whitish. Scape 30−55 cm tall, cylindrical, glabrous, erect, covered by leaf sheaths up to 1/2 of total length. Leaves 5–6, green, glabrous, blade 10−25 cm long, 1–2 mm wide, sub-cylindrical, usually fistulous, with scarcely prominent ribs. Spathe persistent, with two unequal, opposite, erect to sub-erect, subequal valves or shorter than the inflorescence, the large one 5–7 nerved and 1.5–3.5 cm long, the small one 3–5 nerved and 1–2 cm long. Inflorescence globose, 2.5–5 cm in diameter, 40−110 flowered; pedicels erect, unequal, 8–20 mm long. Perigone campanulate, with tepals white, elliptical, truncate to rounded at the apex, 3−3.2 mm long, the outer ones 1.5–1.7 mm wide, the inner ones 1.8−2.2 mm wide, midrib green, vanishing. Stamens included in the perigone or slightly exserted, fully exserted at flowering peak, filaments simple, white, unequal, the outer ones 1−1.2 mm long (up to 2 mm at flowering peak), the inner ones 1.4−2 mm long (up to 2.5 mm at flowering peak), connate below into an annulus 0.5−0.7 mm high; anthers yellow, ovate, broadly apiculate at the apex, 1.2–1.3 × 0.7–0.8 mm. Ovary sub-ellipsoid, bulging in the middle, whitish with lateral green striae, smooth, 2.5−3 mm long; style white, 0.5−0.8 mm long. Capsule trivalved, subglobose, green at maturity, 3–3.5 × 3.3–3.6 mm. Seeds not examined.

Etymology:—The specific epithet refers to “ Ramon ”, a locality in the Negev region (South Israel) where this taxon occurs.

Phenology:—Flowering from mid July to late August; fruiting August-September.

Karyology:—Similarly to the topotypical plants, all investigated specimens of A. nazarenum subsp. ramonense revealed a diploid chromosome complement 2n = 16 ( Fig. 6A ). Furthermore, the karyotype structure is very similar to the subsp. nazarenum , consisting of more or less metacentric chromosomes, except one micro-satellited submetacentric pair. One metacentric pair has always macro-satellites on the short arms ( Fig. 6B ). The karyotype formula can be specified as 2 n = 2x = 16: 10m + 2 mMsat + 2msm + 2 smsat. Differences with the typical specimens of A. nazarenum exclusively concern the relative size of some chromosome pairs, such as the satellited ones and the msm types, which occupy a different position in the idiogram. Total haploid chromosome complement was 81.7 ± 6.9 μm long. Absolute chromosome length ranges from 13.97 ± 1.5 μm of the longest chromosome to 9.53 ± 0.8 μm of the shortest, while the relative length varies from 7.48 ± 0.4% to 5.11 ± 0.2%. All measured karyo-morphometric parameters from specimens of type locality are listed in Table 2. Specimens coming from other localities (e.g. Yerokham and Dimona) only show weak differences chiefly regarding single chromosome size and related karyo-morphometric parameters.

Leaf anatomy:— The leaf cross section of A. nazarenum subsp. ramonense is very similar to that one of the typical subspecies, but generally smaller. However, it differs in having inconspicuous ribs, palisade tissue one-layered, thinner spongy tissue and smaller vascular bundles ( Fig. 3B ).

Distribution and ecology:—This subspecies replaces the typical one in the Negev desert (southern Israel) ( Fig. 4 B ). According to Ighbareyeh et al. (2014), the bioclimate of this area falls within the infra-Mediterranean thermotype, with a dry or arid ombrotype (annual rainfalls between 50-200 mm). Usually, subsp. ramonense occurs in dwarf shrub communities of rocky steppes and hammada hills on various substrata, such as sandstones, limestones and basaltic rocks. The vegetation is dominated by hemicryptophytes and chamaephytes belonging to the Irano-Turanian and Saharo-Arabian elements ( Danin 1983, Ward et al. 1993).

Additional specimens examined: ― ISRAEL. Negev, about 10 km E of Beersheba, Khashin , 29 May 1942, Zohary & Feinbrun s.n. ( HUJ!) ; Negev, km 102 on Jerusalem Beersheba road, 28 May 1942, Zohary s.n. ( HUJ!) ; Negev , env. de Dimone, March 1961, Zohary s.n. ( HUJ!) ; Negev, between Kurnub and Beersheba dunes, 27 May 1934, Eig, Feinbrun & Zohary s.n. ( HUJ!) ; Negev , 300 m S of Ruhama, 23 April 1970, Berlmer s.n. ( HUJ!) ; Negev, Rakhma ridge, 22 April 1964, Danin s.n. ( HUJ!) ; Negev, near Kefas, Yeroham sands, 4 May 1969, Kollmann 399 ( HUJ!) ; Negev, Yerucham , esemplare coltivato, June 1990, S. Brullo s.n. ( CAT 059181 !) ; Negev, Nahal Nitzone , 19 April 1969, Kollmann 376 ( HUJ!) ; Negev, Har Aricha, Saf Kefar , Yeroham , 19 April 1967, Danin 384 ( HUJ!) ; Negev, Arad , 11 April 1967, Feinbrun s.n. ( HUJ!) ; Negev, Har Hanegev, Nahal Elot , Elot cliff, 27 May 1952, Shmida, Gilboa & Luna s.n. ( HUJ!) ; Judean Desert, E of Bani Na’im, Senon-Compain , crumbling rock, northen exposure, 11 May 1934, Eig, Zohary & Feinbrun 6701 ( HUJ!) ; Judean Desert, betw. Tagola and Ein Gedi , Ras dei Allh , deep light soil, N-NE exposure, 13 May 1934, Eig, Zohary & Feinbrun 6725 ( HUJ!)

Taxonomic relationships:—As widely highlighted in literature ( Zahariadi 1975, Brullo et al. 2001, 2003a, 2004, 2007, 2008a, 2008b, 2009, 2010, Tzanoudakis 2000, Biel et al. 2006, Peruzzi 2007, Tzanoudakis & Kypriotakis 2008, Bogdanović et al. 2008, 2009, 2011, Trigas et al. 2010, Koçyiğit & Özhatay 2012), Allium sect. Codonoprasum includes several groups of species morphologically quite distinct, thus suggesting the existence of different evolutionary lines. In particular, the investigations carried out on A. nazarenum show that it is closely related to the species of the A. staticiforme group, occurring in the eastern Mediterranean area. According to Brullo et al. (1995), the A. staticiforme group is well distinguished from the other species of A. sect. Codonoprasum in many quite constant diacritical characters like more or less globose inflorescences with two long appendiculate spathe valves, small perigone, with white to pink tepals 2–4 mm long, stamens exserted from perigone, ovaries with inconspicuous nectariferous pores and very small capsule. Despite these similarities, the comparative morphometric analysis ( Table 1) pointed out that A. nazarenum differs from A. staticiforme s. str., which exclusively occurs in some Cyclades islands and Evvia ( Greece), in having solitary bulbs with darker tunics, taller scapes, larger spathes with different direction, often larger inflorescences, white tepals of different shape, shorter stamen filaments, and different shape of anthers, ovaries, and capsules. Furthermore, the two species have different ecological requirements, since A. nazarenum grows in inland garigues and steppic vegetation, while A. staticiforme is linked to coastal places, usually on sandy substrates. There are also significant karyological differences, because investigations on specimens from the locus classicus (Brullo et al. unpublished data), as well as from other Aegean localities ( Brullo et al. 1995), revealed that karyotypes of Allium staticiforme are formed by 4 metacentric pairs (m), 1-2 of which are microsatellited on the short arms, 3 meta-submetacentric (msm) and 1 submetacentric (sm) pairs. Microsatellites were sometimes detected in the short arms of the submetacentric chromosomes. The karyotype formula of Allium staticiforme can be resumed as follows: 2 n = 2x = 16: 4m + 4 msat + 6msm + 2 smsat.

Herbarium investigations revealed that previously collected specimens of Allium nazarenum were erroneously referred to A. pallens (= A. coppoleri ), a pan-Mediterranean species also widespread in Israel ( Kollmann 1985, 1986, Feinbrun-Dothan & Danin 1998, Brullo et al. 2003a). This was likely due to some morphological resemblances in the subglobose and compact inflorescence, white flowers, and anthers exserted from the perigone. Notwithstanding, many diacritical characters, mainly regarding general habit, leaves, spathe valves, flower traits and fruits, allow clearly to distinguish the two species ( Table 1). Allium pallens has scape much taller, semi-cylindrical and wider leaves, divaricate-patent and longer spathe valves, longer flower pedicels, bigger tepals, longer stamen filaments, elliptical and rounded anthers, bigger ovary, longer style, subglobose-ovoid and bigger capsule. In addition, A. pallens is usually linked to synanthropic habitats and shows a tetraploid chromosome complement (2 n = 32) with a diploidized karyotype arrangement and chromosome formula 2n = 4x = 32: 26m + 2 msat + 4sm (Brullo et. al. 2003).

Allium nazarenum is also morphologically close to A. convallarioides Grossh. in Grossheim & Schischkin (1924: 28), a diploid species occurring in Anatolia and closely allied to A. pallens , but linked to natural environments ( Brullo et al. 2003b). The two species have spathe valves and inflorescences with comparable size, white tepals, exserted stamens, ellipsoid and smooth ovaries, as well as similar ecological requirements. Nevertheless, Allium convallarioides differs from A. nazarenum in having membranaceous bulb tunics, divaricate-reflexed spathe valves, a campanulate perigone with longer tepals, longer stamen filaments, interstaminal teeth, elliptical, apiculate and longer anthers, longer style, and bigger capsule ( Table 1). Allium convallariodes also has a diploid chromosome complement with 2 n = 16 (Brullo et. al. 2003b), which is mostly characterized by more or less metacentric chromosomes, with 1-2 pairs verging towards the meta-submetacentric type, and 1 submetacentric pair. Macro-satellites occur on the short arms of one msm pair. The chromosome formula is 2 n = 2x = 16: 12m + 2 msmsat + 2sm.

Another species closely allied to Allium nazarenum is A. myrianthum Boissier (1844: 59) , occurring in western Anatolia ( Kollmann 1984). Based on investigations on living material from several populations, Allium myrianthum differs from A. nazarenum in its more robust habit, with much taller scape, divaricate-reflexed spathe valves, longer pedicels, smaller tepals, longer stamen filaments, elliptical sub-rounded anthers, obovoid rugose and smaller ovary, and smaller capsule ( Table 1). Moreover, Allium myrianthum is a hygrophilous species linked to damp soils, has a diploid chromosome complement (2 n = 16) rather different from that one of A. nazarenum , characterized by only metacentric chromosomes, with 1-2 micro-satellited pairs ( Brullo et al. 1995). Its karyotype formula is 2 n = 2x = 16: 12m + 4 msat.

Observations on specimens of Allium nazarenum coming from different localities revealed a considerable morphological variability chiefly regarding some diacritical characters, as well as different ecological preferences, which led to separate distribution ranges. These differences suggest that Allium nazarenum includes two distinct taxa which have been treated at sub-specific level. In particular, subsp. nazarenum is confined to the central-northern part of Israel featured by more mesic climatic conditions, while subsp. ramonense is linked to sub-desertic territories of the Negev area (southern Israel). In conclusion, these two taxa may be considered as vicariants, likely arisen as a consequence of a geographical and ecological isolation.

Figures

FIGURE 3. Leaf cross sections of Allium nazarenum subsp. nazarenum (A) and subsp. ramonense (B), based on living material coming from the type localities.

FIGURE 4. Distribution map of Allium nazarenum subsp. nazarenum (A) and subsp. ramonense (B), based on hebarium specimens.

FIGURE 5. Diagnostic features of Allium nazarenum subsp. ramonense. A. Habit. B. Flowers. C. Perigones and stamens open. D.Anther. E. Pistil. F. Capsule. G. Spathe valves. Illustration by S. Brullo based on living material coming from the type locality (CAT).

FIGURE 6. Chromosome complement (2n = 16) of Allium nazarenum subsp. ramonense. Mitotic metaphase plate from the type locality (A), arrows indicate satellited chromosomes, and idiogram (B).