Isoetes vanensis, 2016

Keskin, Golshan Zare Mustafa, Doğru-Koca, Asli & Armağan, Metin, 2016, Isoëtes vanensis (Isoëtaceae) sp. nov. from Turkey, Phytotaxa 269 (4), pp. 294-300 : 295

Isoëtes vanensis Keskin & G. Zare , sp. nov. ( Figure 1 ).

Type:— TURKEY. Van: Gevaş, Artos Mountain, Aşağınarlıca Village, 38°12’17”N, 43°04’40”E, 2013 m, 24 June 2015. G. Zare 1103 with A.D. Koca, M. Armağan and M. Fidan (holotype HUB!, isotypes ANK!, ISTE!, NGBB!).

Diagnosis: — Isoëtes vanensis is most similar to I. delilei Rothmaler (1944: 72) [= I. setacea Lamarck (1789: 314) ], but the former is distinguished from the allied species by its number of leaves, papery scales, ligule shape, small macrospores with secondary ornamentation, small microspores with low aculeate ornamentation and thick triradial ridges with long aculeate ornamentation.

Plants grasslike, heterosporous, amphibious. Cormus 8–12 mm diameter, brown with 3-lobed. Scales present, old leaf-bases sometimes present and forming a white bulb, papery scales but absent black lignified scales or phyllopodia. Leaves 8–15, light green, white at base, canaliculate, angular to semi-terete, spirally arranged, linear, 10–25 cm long, erect or somewhat spreading, very large membranous at base, 8–20 mm wide, acute at tip. Stomata present. Ligules deltoid to subcordate, 0.7–1.5 mm, membranous, inserted above sporangium; labium not obvious. Megasporophylls in outer circle and numerouse; microsporophylls placed in central cycles and a few. Velum completely absent. Sporangia solitary, ellipsoid to subglobose, 4–5 mm. Megasporangium containing many megaspores; megaspores trilete, 400–500 μm, globose, low tuberculate; surface and tubercules with fimbriate-acuelate secondary ornamentation; triradial ridge (laesurae) thick and prominent with long acuelate; equatorial ridge (cingulum) thick and prominent with long acuelate; white when dry; secondary ornamentation dense, thin, longer than wide, fimbriate-aculeate like a star. Microsporangium containing thousands of microspores. Microspores monolete, grey, ellipsoid, 23–31 μm, low aculeate, equatorial ridges present ( Figures 2–3 ).

Spore time: June–July.

Etymology:— The species epithet refers to the place from which the type specimens was collected for the first time.

Habitat:— Seasonal ponds.

Associated plants:— Butomus umbellatus Linnaeus (1753: 372) , Ranunculus flammula Linnaeus (1753: 548) , Scrophularia ilwensis C. Koch (1843:284) , Gladiolus kotschyanus Boissier (1844: 141) , Cypraceae and Poaceae members.

General distribution:— Turkey; endemic.

Figures

FIGURE 1. Isoëtes vanensis. A. Habit; B1. Megasporophylls; B2. Microsporophylls; C. Macrospore; D. Microspore.

FIGURE 2. Isoëtes vanensis. A. Habitat; B. A general appearance.

FIGURE 3. Isoëtes vanensis. A. Macrospores general appearance; B. Single macrospore- polar view; C. Single macrospore- back view; D. Macrospore ornamentation view of polar; E. Microspores; F. Microspore ornamentation.