Lythrum netofa Vered, Mazar & Gazaix 2020, sp. nov.
Creators: name: Gazaix, Antoine
name: Mazar, Shmuel
name: Vered, Shir
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Lythraceae
Lythrum
Lythrum netofa

description: Lythrum netofa Vered, Mazar & Gazaix, sp. nov. Figure 1.
TYPE:— ISRAEL, Lower Gallilee: Beit–Netofa valley, temporary flooded fields near a canal, 32.825N, 35.378E, 150 m, 8 July 2019, Mazar 9 (holotype: HUJ!, isotypes: E!, G!, MPU!, PAL!).
Diagnosis:—The new species is morphologically close to Lythrum acutangulum Lagasca (1816: 16) due to its winged floral tube, but has homostylous flowers (versus heterostylous in L. acutangulum) with four petals (vs. six), and a larger capsule (Castroviejo Bolibar et al., 1997). For others close species, Lythrum netofa differs from all heterostylous species (e.g. Lythrum salicaria or Lythrum junceum Banks ex Solander (in Russel 1794: 253)) by its small flowers with included sexual organs. Within the other species, it differs from Lythrum silenoides by its teeth number on the floral tube (8 and not 12), its petal number (4 and not 6) and its style length; and from Lythrum thesioides by its higher number of stamens (6–8 and not 4), and ungeminate flowers. Those two last species have been recently discovered from Israel (Mazar, & Oron, 2019). Finally, in 2012, plants observed and reported from the same area in Israel, were misidentified as L. thymifolia Linnaeus (1753: 447) (Danin & Fragman-Sapir, 2019). However, it differs from it by its winged floral tube, its higher number of stamens (6–8 and not 2), and its very high number of seeds per capsule. Seed number per capsule can also easily distinguish it from Lythrum hyssopifolia (<30 seeds per capsule), L. netofa also differs from L. hyssopifolia by its floral tube (winged and not conical) and by its petal number (4 and not of 6). Detailed comparisons with the three closest species, all of them present in Israel, are presented in Table 1.
Description: —Annual plant, 5–30 cm high, glabrous, stem quadrangular, slightly winged up to 0.5 mm, branched mostly at the bottom, sometimes to the middle. Leaves sessile, entire, oblong, broad base, apex acute. Lower leaves opposite (first 6–8), up to 30 mm long × 8 mm wide, upper leaves alternate, smaller (<10 mm long).
Flowers homostylous, solitary, axillary, pedicels up to 1 mm, bracts two, <1mm long. Floral tube 5–7 mm long and 1.5–2 mm wide, slightly campanulate, angular, with four prominent wings, ending in subulate teeth 1–1.5 mm long, pointing upwards and to the exterior. Inner teeth between the outer, 4, small. Four petals, pink-violet with darker veins, obovate, 3–4 mm long and 2 mm wide. Stamens six to eight, included in the floral tube and inserted at different positions along it. Ovary elongated, cylindrical, 2–2.5 mm long. Style 1–1.7 mm long, shorter than the ovary. Stigma round, inclusive at flowering. Mature capsules cylindrical, 4–5 mm long, sometimes slightly exceeding the floral tube when mature, carrying dry style and stigma, containing an average of 140 seeds (range: 90 to 170). Seeds about 0.4 mm long and 0.25 mm wide, attenuate-oval with a pointed extremity.
Etymology:—The name refers to the area where the plant was found.
Phenology:—The plant flowers from late June to August.
Ecology and conservation status:—The plant is currently known from the Beit-Netofa valley. Eight small populations were observed (collections + field observations), with less than 100 individuals each, distanced few hundreds of meters away. All inside an area of about 4 km ², which is one very small locality. The habitat is along the banks and sides of a 5 km long, man-made canal, that was made to drain the flooded fields during the winter. The canal dries out during the summer. The plant grows at 150 m elevation, on “dark brown” soils with 70–75% clay. The neighboring fields are cultivated in traditional agriculture, mainly cereals (wheat) and vegetables. The plant grows with other annual species of temporary wetlands including Lythrum tribracteatum Salzmann ex Tenore (1830: 13), L. hyssopifolia Linnaeus (1753: 447), Ammannia baccifera Linnaeus (1753: 120) and species of Crypsis Aiton (1789: 48). In water stress conditions, the leaves are tightly pressed against the stem.
Perturbation of the soil made for agriculture, like ploughing or ruts, may be beneficial for the plant by reducing competition and exposing seeds to light, as known for Lythrum thesioides M. Bieberstein (1808: 367) (Gazaix et al., 2019). Indeed, annual Lythrum species and several species of Mediterranean temporary wetlands produce small seeds of high longevity, and thus develop seed banks that can stay decades in the soil, until favorable conditions stimulate germination (Aponte et al. 2010; Gazaix et al. 2019). The agricultural context of the Beit-Netofa valley, and its anthropized hydrology (canal) represent thus both possibilities for management and threats if sudden changes in land use or hydrology disturb the sites. This is even more important as these populations are the only known occurrence of this species, thus they are of very high conservation value. IUCN Conservation status assessment would require more field explorations, in order to have a better information on the distribution and the demography of the species. Thus, botanists of the Israel Nature and Parks Authority were reported about the species, and we hope now that study of the spread of the species will allow exact assessment of the conservation status.
Paratypes:— ISRAEL, Lower Gallilee: Beit–Netofa valley, temporary flooded fields near a canal, 32.825N, 35.380E, 1 July 2017, Mazar 6 (HUJ!); 32.815N, 35.361E, 5 July 2017, Mazar 7 (HUJ!); 32.820N, 35.355E, 20 July 2017, Mazar 8 (HUJ!).
description: Published as part of Gazaix, Antoine, Mazar, Shmuel & Vered, Shir, 2020, Lythrum netofa (Lythraceae) a new species from a temporary flooded plain of Israel, pp. 47-50 in Phytotaxa 437 (1) on pages 47-49, DOI: 10.11646/phytotaxa.437.1.6, http://zenodo.org/record/13875050