Limonium lanfrancoi Agius, Galea, Cambria, Giusso

Agius, Dolores Rita, Galea, Maria Elizabeth, Cambria, Salvatore, Galdo, Gianpietro Giusso Del & Brullo, Salvatore, 2023, Taxonomic survey on the genus Limonium in the Maltese islands, with description of a new species, Phytotaxa 622 (2), pp. 99-114 : 102

Limonium lanfrancoi Agius, Galea, Cambria, Giusso del Galdo & Brullo sp. nov. ( Fig. 1 ).

Type: MALTA. Islet of Cominotto (loc. Kemmunett), north-west rocky coast. 9 October 2022, D. R. Agius & M. E. Galea s.n. (holotype CAT!, isotypes CAT!, ARG!) .

Limonio melitense affinis, sed distincto scapo contracto, breviore, foliis brevioribus, spicis brevioribus, spiculis brevioribus, bractea exteriore breviore, bractea superiore breviore, calyce breviore, ex bractea superiore 1,5–2,5 mm exserto, tubo breviore, lobis triangulari-ovatis.

Plant perennial, glabrous, with short caudices. Leaves green, rigid, laxly inserted on the caudices, spathulate, 1–nerved, 5–20 mm long, 2–5 mm wide, often slightly revolute at the margin, rounded at the apex, usually withered at anthesis. Stem several, rigid, erect, 5–12 cm tall, densely branched from the base, obtrullate in outline, with numerous much branched sterile branches. Articles slightly arched, 2–12(–15) mm long, with deepened glands, forming branching angles of 20–30°. Fertile branches localized at the top of the stem. Spikes 5–25 mm long, straight, with 2–6(8) spikelets. Spikelets 5–6 mm long, 3–4 per cm, 1–3 flowered. Outer bract 1–1.4 mm long, ovate, acute, coriaceous in the central part, forming an apiculum 0.5–0.6 mm long, membranous at margin. Middle bract membranous, rounded, 1.5–1.8 mm long. Inner bract 3.8–4.3 mm long, 2–2.5 mm wide, elliptical, rounded, with outer hyaline margin and pale brown inner margin, central part herbaceous, with an apiculum 0.5–0.8 mm long, not reaching the apex. Calyx 4.5–5 mm long, sparsely hairy in the tube, 1.5–2.5 mm protruding from the inner bract, with tube 1.2–1.5 mm long and limb 3.3–3.5 mm long, with midribs ending at the base of the lobes, which are triangular–ovate, 0.6 mm long.

Etymology: — This species is dedicated to Edwin Lanfranco (1946) Maltese botanist author of several contributions aimed at improving the floristic knowledge of this small but interesting insular territory of the Mediterranean.

Phenology: — Limonium lanfrancoi flowers from July to October and producing seeds from August to November.

Distribution and ecology: — Based on current knowledge, L. lanfrancoi is localized exclusively on the uninhabited islet of Cominotto, which, with the island of Comino, delimits the well-known Blue Lagoon of the Maltese archipelago ( Fig. 5 , 7 ). This species, occurring on coralline limestone, constitutes a small population distributed along the northern and western coast of this islet, ( Fig. 6 ) where it is a member of a plant communities belonging to Crucianellion rupestris , alliance of the Crithmo-Limonietea ( Brullo et al. 2020). Usually it grows with Frankenia hirsuta Linnaeus (1753: 331) , Silene sedoides Poiret (1789: 164) , Crucianella rupestris Gussone (1832: 44) , Daucus rupestris Gussone (1843: 335) , Limbarda crithmoides ( Linnaeus, 1753:883) Dumortier (1827: 68) subsp. longifolia ( Arcangeli 1882: 371) Greuter (2003: 244) , Cichorium spinosum Linnaeus (1753: 813) , Anyhyllis hermanniae Linnaeus (1753:720) subsp. melitensis Brullo & Giusso (2006a: 309) , etc.

Conservation status:— Limonium lanfrancoi is localized exclusively on the islet of Cominotto (0.06 km 2), which is just 200 m. from Comino island , in the Gozo Channel, where it is represented by a small population of more than a thousand individuals, distributed along the coast. This species grows mainly in the belt near the sea, directly affected by marine aerosol, habitat fortunately still not threatened by anthropic pressures as the summer tourism. Therefore according to the IUCN Red list category ( IUCN 2023), this species for its restricted distribution, low number of mature individuals and absence of threats that can modify the natural environment, should be considered as Critically Endagered B 1 + B2 a, b (ii,iii) .

Specimens examined (Paratypes):— MALTA. Islet of Cominotto (loc. Kemmunett), northern rocky coast. 24 November 2021, D. R. Agius & M. E. Galea s.n. (CAT!); Islet of Cominotto, western rocky coast. 19 April 2023, D. Agius & S. Cambria s.n. (CAT!); Cominotto south-eastern coast, 19 April 2023, D. Agius & S. Cambria s.n. (CAT!) .

Figures

FIGURE 1. Diagnostic features of Limomium lanfrancoi. A. Habit. B. Stem article. C. Inflorescence. D. Spikelets. E. Inner bracts in lateral view. F. Inner bracts in dorsal view. G. Middle bracts. H. Outer bracts. I. Calyces. J. Calyx lobes. Illustration by S. Brullo based on living material coming from the type locality (CAT).

FIGURE 5. Geographical distribution of Limomium lanfrancoi (red dot) in Cominotto. From Google Earth (modified).

FIGURE 6. Phenological features of Limonium lanfrancoi from Cominotto. A–C. Individuals in natural habitat. D–E. Rocky coast with L. lanfrancoi. F. Blue Lagoon between Comino and Cominotto. (Photos A–D by M. E. Galea, E–F by S. Cambria).

FIGURE 7. Distribution of Limonium species in the MalteseArchipelago.Green dots:Limonium melitense; blue dots:Limonium virgatum; purple dots: Limonium zeraphae; red dot: Limonium lanfrancoi. It is based only on examined specimens listed in the paper.