Callitriche brutia var. naftolskyi (Warburg & Eig) Lansdown, 2017

Lansdown, Richard V., Bazos, Ioannis, Caria, Maria Carmela, Troia, Angelo & Wieringa, Jan J., 2017, New distribution and taxonomic information on Callitriche (Plantaginaceae) in the Mediterranean region, Phytotaxa 313 (1), pp. 91-104 : 92-93

Callitriche brutia var. naftolskyi (Warburg & Eig) Lansdown comb. nov. Callitriche naftolskyi Warburg & Eig (1929:

84), basionym.

Lectotype (designated here; cited but not formally designated by Schotsman 1967): ISRAEL. Sharon Plain , north-east of Tel Aviv, 23 April 1927, Naftolsky No. 01853 ( HUJ) [not seen].

Callitriche brutia var. naftolskyi has been overlooked, dismissed as a synonym of C. brutia Petagna (1787: 10) var. brutia or treated as unresolved by most authors (e.g. Schotsman 1967, Schotsman 1977, Lansdown 2008). However, a chance encounter by RVL with populations agreeing with the description of C. naftolskyi at a number of sites during the International Symposium on Mediterranean Temporary Ponds held in Sassari in 2015, led to a re-evaluation of its status which is here regarded at the varietal rank (see below).

Callitriche naftolskyi was described as a new species by Warburg & Eig (1929), based on material from the Sharon Plain, NE of Tel Aviv in Israel (lectotype: Naftolsky 01853, HUJ; cf. Schotsman 1967). Subsequently, Schotsman (1967) initially considered single specimens from Sardinia (Huet de Pavillon s.n. 1854, P) and Morocco (Nègre 4876, RAB) to be C. naftolskyi , but then expressed doubt ( Schotsman 1977) and ultimately assigned them to C. brutia ( C. brutia var. brutia ). She also annotated a specimen from Palermo (Birch s.n. 1854, K) “probably C. pedunculata De Candolle (in Lamarck & Candolle 1805: 415) (= C. brutia var. brutia ) with some big fruits and broad winged seeds”, but this material clearly conforms to the original concept of C. naftolskyi . The discovery of populations in Sardinia prompted review of material from the Isola di Capraia, formerly identified as C. regis-jubae Schotsman (1974: 25) (cf. Lansdown et al. 2014) and this was also shown to agree with the description of C. naftolskyi . Fieldwork in April 2016 revealed C. brutia var. naftolskyi to be fairly widespread in suitable habitat in Sardinia and present in at least two seasonal pool complexes in Sicily. Furthermore, review of herbarium specimens also revealed specimens from Greece (Lesvos and Milos), Libya, Morocco and Syria. This review of the literature and herbarium specimens suggests that C. brutia var. naftolskyi is endemic to but widespread within the Mediterranean basin, occurring on larger islands and in North Africa east to the Middle East.

The following description is based on a combination of biometrics from material collected at a range of sites in Sardinia in April 2016, together with information from the protologue ( Warburg & Eig 1929) and details provided by Schotsman (1967): Stem much-branched, supported by water or when terrestrial, prostrate and creeping. Stem scales with 10–19 cells, often irregular in outline; axillary scales fan-like with 6–8 cells. Floating leaves narrowly elliptic, at most very shallowly notched at the apex, 1.3–2.4 mm wide × 2.5–4 mm long, petiole 0.3–2.3 mm, with 3–5 veins, terrestrial leaves typically smaller. Bracts apparently lacking; flowers solitary in leaf axils, the most frequent pattern involves a male flower opposed by a female; pollination appears to be through self-fertilisation; anther average 0.3–0.4 mm wide × 0.3 mm high; stigma 0.6–1 mm long, persistent, initially reflexed, then appressed to the side of the fruit; peduncle 4–12 mm; fruit 0.9–1.6 mm wide × 1–1.5 mm high; wing 0.02–0.1 mm, radial thickenings in the wings are very branched and interlinked; toward the base of the wing there are often polygonal cells aligned in radiating directions, continuing the mesocarp cells.

Five Callitriche taxa in the Mediterranean region produce winged, pedunculate fruit. Of these, both C. mouterdei Schotsman (1969: 617) and C. regis-jubae have persistent bracts approximately 1 mm long, long filaments (at least post-anthesis), yellow pollen and erect or recurved styles. Callitriche brutia var. naftolskyi lacks bracts, the anther is subsessile, pollen is colourless and the style is strongly reflexed and soon appressed to the side of the fruit. Callitriche truncata Gussone (1826: 4) subsp. truncata differs from C. brutia var. naftolskyi in its leaves which are always singleveined, and lack of peltate scales on the stem and leaves. Callitriche brutia var. naftolskyi can be distinguished from C. b. var. brutia by the wings on mature fruit which are wider and have an undulate margin; the fruit are matt (shiny in var. brutia ); the style is persistent and the fruit typically wider than long, although this can be difficult to measure because of the shape of the wing. Although C. b. var. naftolskyi differs from C. b. var. brutia in a number of ways, these are insignificant compared to the characters separating most species within the genus, and pending molecular clarification it is appropriate to treat C. naftolskyi as a variety within C. brutia as C. brutia var. naftolskyi . It is of note that the genome is the same size in both C. brutia var. brutia and C. b. var. naftolskyi (J. Prancl pers. comm.).

Callitriche brutia var. naftolskyi has not been found with subsessile fruit. All fruit are pedunculate including young, green ones with peduncles 4 mm or more in length, even in aquatic material, and most fruit are on peduncles 10 mm or more in length. This differs from C. brutia var. brutia which has subsessile fruit when growing in water, but pedunculate fruit when terrestrialised ( Lansdown 2008). Warburg & Eig (1929) suggested that the fruits of C. naftolskyi penetrate the soil vertically which is considered by Schotsman (1967) unlike C. brutia and to more closely resemble C. deflexa A. Braun ex Hegelmaier (1864: 58) . However, this is not a very reliable difference given that the direction of entry into the soil and even whether fruit grow under a mat of vegetation or penetrate into the soil, depends very much on the nature of the substrate in which the plant is growing.

In Sardinia and Sicily C. brutia var. naftolskyi was recorded exclusively from temporary wetlands, both in wellknown species-rich sites such as the seasonal pool complexes at Giara di Gesturi and Monte Minerva in Sardinia and a wetland complex near Buccheri and pools at Castello della Pietra in Sicily; but also in a relatively banal ditch running through pasture east of Perdasdefogu in eastern Sardinia. In these sites it was recorded from a variety of habitats, all of which are seasonally inundated, including deeply rutted areas on tracks, pools and hollows in pasture, as well as open shallow hollows and a cupular pool on limestone “pavement”. In Sicily and Sardinia, C. brutia var. naftolskyi was most frequently recorded with a range of species characteristic of seasonal pools such as Bellis annua Linnaeus (1753: 887) , Carex divisa Hudson (1762: 348) , Crassula vaillantii ( Willdenow 1798: 720) Roth (1827: 992) , Eryngium barrelieri Boissier (1844: 125) , Juncus pygmaeus Richard ex Thuillier (1800: 178) , Lythrum hyssopifolia Linnaeus (1753: 447) and Ranunculus ophioglossifolius Villars (1789: 731) ; less often with Apium crassipes (W.D.J. Koch ex Reichenbach 1825: tab. 21) Reichenbach (1863: 9), Callitriche brutia var. brutia , C. stagnalis Scopoli (1772: 251) , Chamaemelum nobile ( Linnaeus 1753: 894) Allioni (1785: 185) , Corrigiola litoralis Linnaeus (1753: 271) , Damasonium bourgaei Cosson (1849: 47) , Isoetes species (including I. histrix Bory 1844: 1167 , I. longissima Bory 1844: 1165 , and I. tiguliana Gennari 1861: 42 ), Lythrum borysthenicum (M.Bieb. ex Schrank 1822: 643) Litvinov (1917: 209) , L. thymifolia Linnaeus (1753: 447) , Mentha pulegium Linnaeus (1753: 577) , Myosotis sicula Gussone (1843: 214) , Pilularia minuta Durieu in Bory & Durieu (1848: plate 38, figs. 120), Ranunculus muricatus Linnaeus (1753: 555) and R. revellieri Boreau (1857: 85) . It was also recorded once with each of the following species varying from what may be described as “true” aquatics such as Ranunculus aquatilis Linnaeus (1753: 556) and R. peltatus Schrank (1789: 103) , through species typical of seasonal pools such as Antinoria insularis Parlatore (1845: 93) and Juncus heterophyllus Dufour (1825: 88) , to those which rarely, if ever actually grow in water but are characteristic of damp ground including Cicendia filiformis ( Linnaeus 1753: 231) Delarbre (1795: 20) , Juncus bufonius Linnaeus (1753: 328) , J. capitatus Weigel (1772: 28) and Pulicaria sicula Moris (1840: 363) .

No assessment of the extinction risk of C. brutia var. naftolskyi has been published, the extent of its range, combined with the occurrence of extensive populations in many different water bodies in Sardinia and Sicily mean that it should be classed as Least Concern ( IUCN 2012).