Isoetes jarmaniae D.F.Brunt., G. Kantvilas & M. Garrett, 2021

Brunton, Daniel F., Garrett, Michael, Sokoloff, Paul C. & Kantvilas, Gintaras, 2021, Description, distribution and ecology of endemic Tasmanian quillwort, Isoetes jarmaniae, sp. nov. (Isoetaceae; Lycopodiopsida), Phytotaxa 522 (1), pp. 27-37 : 29-30

Isoetes jarmaniae D.F.Brunt., G. Kantvilas & M. Garrett , sp. nov. ( Figures 1 , 4 , 5 , 6 )

Diagnosis:— A diminutive species restricted to alkaline seepage areas in Tasmanian buttongrass moorland and most similar to the larger Isoetes drummondii , from which it differs most conspicuously by its strongly recurved leaves, disproportionately large ligules and congested, boldly ornamented regulate-cristate to columnar, slightly triangular megaspores and finely papillate microspores.

Type: — AUSTRALIA: Tasmania, Maxwell Valley near Lancelot Hill , 42°31’S 145°55’E, in alkaline pan, 190 m elevation, 26 April 1985, S. J. Jarman (holotype HO 314939!; isotype DFB! [fragment]) .

Description:— PLANTS: short (leaf rosette above corm <6 cm tall), amphibious, herbaceous ( Figure 1 ), arising from an approximately 0.75−1.00 cm wide, three-lobed corm (rhizomorph); LEAVES: spirally arranged, simple, dull blackish to gray-green with lighter bases, 1.0− 2.3 mm wide at mid-point (dried), thin-walled, typically distinctly flattened and longitudinally folded adaxially in the lower half and terete upwardly (some terete throughout); alae extend approximately 20% length of leaf; small central vascular bundle and narrow internal partitions create four atypically wide air chambers ( Figure 4 ); SPORANGIA: oval, 3.0 × 2.4 mm, inserted into the basal inner side of the leaves, uniformly dark tan to brown; surface unmarked; fenestra complete (no velum coverage) ( Figure 5 ); LIGULE: narrowly long-triangular with obtuse to acute summit, 60–80% length of the sporangium ( Figure 5 ); MEGASPORES: globose body, averaging 660 µm in diameter; congested ornamentation of distinct, thick walled, rugulate-cristate muri (walls) and/or tall, narrow, columnar muri (echinate-like appearance); low papillae evident on distal side of some otherwise smooth-walled, thin, alate equatorial ridges; slightly triangular megaspore shape results from subtle to prominent swellings (‘knobs’) at the intersections of the equatorial ridge with the suture ridges ( Figures 6 A−6D); MICROSPORES: plump, blunt-ended, with obscure to absent dorsal ridge; averaging 35.6 µm long; densely fine-papillate perispore ornamentation ( Figures 6 E-6F); white to light tan en masse.

Distribution and Habitat:— In coarse, peaty quartzite/ silica sand substrate in periodically inundated (flowing) seepage areas over limestone bedrock, with sparse associated vegetation; found only in southwestern Tasmania, Australia.

Chromosome Number:— Inferred diploid (2 n =2x=22) by spore size conformity with cytologically confirmed diploid Tasmanian taxa: I. drummondii , I. elatior and I. gunnii ( Marsden 1979, D.M. Britton pers. comm.).

Etymology:— The epithet honours Dr. S. Jean Jarman of Hobart, Tasmania, who first collected this species and recognised it as unique. The vernacular name Limestone Quillwort is suggested, as per Tasmanian State Government (2021).

Paratypes: — Tasmania: tributaries of the Giblin River , E of Lawson Range, 42°56’S 145°44’E, J . Jarman ( HO 31378 !); Maxwell Valley , 42°30’S 145°55’E, 190 m, 26April 1985, S. J . Jarman ( HO 314082!); Maxwell River , 42°31’S 145°55’E, 200 m, 26 April 1985, M. J . Brown ( HO 531819!); Middle Giblin River basin, 8 km NW of Mt Gaffney, 43°00’S 145°45’E, 30 m, 17 Feb. 1989, J. R . Croft 10114 & M. M . Richardson ( AD, CANB, HO!); Alfhild Creek, Giblin River Valley , 43°03’S 145°43’E, Feb. 1989, L . Gilfedder ( HO 114427!); Giblin River 43.0156°S 145.7467°E, M . Garrett s.n., 20 February 1994 ( DFB!, OAC); Giblin River , 42°57’S 145°46’E, 20 m, 8 Jan 2005, G . Kantvilas & M . Garrett ( HO 531818!); Giblin River valley , 42°56’S 145°45’E, 40 m, 18 Aug. 2016, M . Visoiu ( HO 591035!); Maxwell River Valley , c. 700 m SW of Prince Rivulet, 42°29’S 145°55’E, 190 m, 12 Dec. 2017, M. F . de Salas 1915 ( DFB (fragment)!, HO 590554!); Algonkian Rivulet valley, c. 800 m NW of junction with Ridge Creek , 42°27’S 145°57’E, 210 m, 12 Dec. 2017, M. F . de Salas 1903 ( DFB (fragment)!, HO 590544!); Giblin Valley , c. 2.75 km SE of Pass Hill, 42°56’S 145°45’E, 40 m, 21 Mar 2018, M. F . de Salas 2005 ( DFB (fragment)!, HO 593072!) .

Figures

FIGURE 1. Isoetes jarmaniae; 1A plants in situ, Maxwell River valley (1979); 1B: excavated plants, Prince Rivulet, Maxwell River valley, December 2017. Scale bar = 2 cm. (Photos: J. Jarman).

FIGURE 4. Cross-section of Isoetes jarmaniae leaves at mid-point, showing narrow internal partitions, small central vascular bundle and large air channels; 4A: terete leaf section (de Salas 2005, Giblin River valley, March 2018, DFB); 4B: flattened (adaxially folded) leaf section (de Salas 1903, December 2017, DFB). (Photo interpretation: D. F. Brunton)

FIGURE 5. Inner leaf base of Isoetes jarmaniae showing complete fenestra (no velum coverage) of the sporangium and long, narrow ligule (Jarman s.n., near Lancelot Hill, Maxwell River valley, April 1985, DFB). Scale bar = 1 mm. (Photo: D. F. Brunton)

FIGURE 6. Isoetes jarmaniae spores; 3A: megaspore proximal view, with congested ornamentation and slightly triangular shape; 3B: megaspore lateral view, rugulate-cristate ornamentation and papillae in patches on distal side of alate (winged) equatorial ridge; 3C: megaspore distal view, with congested ornamentation pattern of anastomosing, rugulate-cristate, thick-walled muri and with fewer standalone columnar muri; 3D: megaspore distal view, with alternative congested pattern of tall, predominantly columnar muri and a relatively wide (5−9% width of megaspore body), thin, alate equatorial band; note three microspores to left; 3E: plump, blunt-ended microspore with low, obscure dorsal ridge; 3F: detail of densely fine papillate microspore ornamentation. Megaspore scale bar (3A–D) = 100 µm. (3A: Garrett s.n. Giblin River valley, February 1994 (SEM image: D. M. Britton, 1994); 3B & 3C: Jarman s.n., near Lancelot Hill, Maxwell River valley, April 1985 (SEM images: P.C. Sokoloff, June 2021); 3D & 3E: de Salas 2005, Pass Hill, Giblin River valley, March 2018 (SEM images: P.C. Sokoloff, June 2021); 3F: Jarman s.n., near Lancelot Hill, Maxwell River valley, April 1985 (SEM images: P.C. Sokoloff, June 2021))