Levenhookia sonderi (F.Muell.) F.Muell., Fragm. 1(1): 18. 1858, as Leeuvenhookia

Wege, Juliet A., 2020, Styleworts under the microscope: a taxonomic account of Levenhookia (Stylidiaceae), PhytoKeys 151, pp. 1-47 : 1

3. Levenhookia sonderi (F.Muell.) F.Muell., Fragm. 1(1): 18. 1858, as Leeuvenhookia Fig. 3F

Coleostylis sonderi F.Muell., Second systematic index of the plants of Victoria. Victoria, Parliamentary Paper no. A 18: 13. 1854, nom. nud.

Coleostylis sonderi F.Muell., Definitions of rare or hitherto undescribed Australian plants 13. 1855 [see O. Seberg, Taxon 35: 267 (1986) for publication date].

Coleostylis sonderi F.Muell., Trans. Philos. Soc. Victoria 1: 46. 1855, isonym.

Leewenhoekia sonderi , orth. var.: F. von Mueller, Syst. Census Austral. Pl.: 86. 1882.

Levenhookia dubia var. sonderi (F.Muell.) Mildbr. in H.G.A. Engler, Pflanzenr. 35: 27. 1908.

Type.

Australia. Victoria: Violet Creek, C. Wilhelmi s.n. (lectotype, here designated: MEL 1617988 [the individual mounted on the sheet together with those in the large, cream, rectangular packet annotated " Levenhookia Sonderi, Mueller’s”]; isolectotypes: K 000060054, MEL 1617989, MEL 2256398, TDC [3 individuals on right]).

Description.

Annual herb 1-10 cm high. Glandular hairs 0.1-0.7 mm long. Stem pale, green, straw brown or more rarely reddish brown, simple or occasionally with porrect lateral branches, sparsely glandular-hairy. Leaves cauline, scattered, pale green; lamina ovate or orbicular, 1-8 mm long including the petiole, 1-4.5 mm wide, subacute or obtuse, sparsely glandular-hairy abaxially and on the margins. Flowers usually in corymbs or umbels, sometimes in short racemes, 1-ca. 23 per plant; bracts with an ovate or lanceolate lamina, 1-7 mm long including the petiole, glandular-hairy like the leaves; pedicels 0.5-10 mm long, sparsely glandular-hairy. Hypanthium globose, ovoid or ellipsoid, 0.7-2 mm long, 0.7-2 mm wide, with glandular hairs throughout and sparse eglandular hairs 0.4-0.8 mm long distally. Calyx lobes unequal (with the anterior pair longer than the rest), 0.7-1.7 mm long, obtuse or subacute, sparsely glandular-hairy. Corolla white with a yellowish green throat; lobes ± evenly arranged or with the upper (posterior) ones ± paired vertically, rounded or scarcely retuse, sparsely glandular-hairy abaxially; anterior lobes obovate, slightly longer and broader than the posterior pair, ca. 1.2-1.3 mm long, 0.8-0.9 mm wide; posterior lobes elliptic or obovate, ca. 0.7-1 mm long, 0.7-0.8 mm wide; tube yellowish green, 0.8-1.3 mm long, shorter than the longest calyx lobes, sparsely glandular-hairy distally. Labellum ventral, 0.8-1.2 mm long including a ca. 0.2 mm claw; hood dark red-purple, with sparse glandular hairs abaxially, lacking an appendage at the cleft apex; basal appendages white, linear-subulate, 0.3-0.4 mm long. Column sheath yellowish green, glabrous, to 0.3 mm high and irregularly lobed on anterior side, scarcely visible on posterior side, pendulous appendages absent. Column white, seemingly adnate to the anterior side of the corolla tube, 1.8-2.5 mm long with the top ca. 1 mm free, distally angled toward the labellum, glabrous; stigmatic lobes to ca. 0.5 mm long, apparently developing while the column is hooded, erect to scarcely incurved. Capsule globose, ovoid or ellipsoid, 2-3.5 mm long excluding calyx lobes. Seeds 0.6-1 mm long, 0.5-0.6 mm wide.

Diagnostic features.

Levenhookia sonderi has a pale, sparsely glandular-hairy stem, leaves with an ovate or orbicular lamina, glandular and eglandular hairs on the hypanthium, unequal calyx lobes with obtuse to subacute apices, and a red-purple labellum (appearing very dark on pressed material) with white, linear-subulate basal appendages. Its seeds are the largest in the genus.

Phenology.

Flowering September-December; fruiting October-December.

Distribution.

Levenhookia sonderi is endemic to South Australia and Victoria (Fig. 3E ), where it is has been recorded from the Naracoote Coastal Plain, Southern Volcanic Plain, Victorian Midlands and South Eastern Highlands bioregions, extending from Reedy Creek (South Australia) in the west to the Dandenong Ranges (Victoria) in the east.

Habitat.

This species grows in damp sandy loam or clayey sand on hill-slopes or more commonly in lowland areas, including near the margins of swamps. It favours open patches or lightly-disturbed areas in open woodland with Eucalyptus camaldulensis , E. macrorhynca , E. polyanthemos or E. goniocalyx , or near stands of Kunzea phylicoides , and grows in association with other diminutive herbs including L. dubia , Stylidium beaugleholei , S. despectum and S. perpusillum .

Conservation status.

Levenhookia sonderi is listed as Rare in Victoria ( Department of Environment and Primary Industries, Victoria 2014) and Vulnerable (Schedule 8) in South Australia ( Government of South Australia 2018) and may warrant listing at the national level under the Environment Protection and Biodiversity Conservation Act 1999. Populations of this species are isolated and appear highly localised, with the reproductive capacity of some individuals from locations in South Australia and Victoria impacted by a species of smut (see notes below).

Etymology.

Honours German apothecary and botanist Otto Wilhelm Sonder (1812-1881), who described a suite of new taxa as part of his account of Stylidiaceae in Lehmann’s Plantae Preissianae ( Sonder 1845).

Vernacular name.

Slender Stylewort ( Erickson 1958).

Typification.

MEL 1617988, which is annotated by Mueller and was viewed by Bentham (1868) for Flora Australiensis, comprises a mounted individual and an envelope housing five separate packets that represent more than one gathering. The mounted individual and the numerous additional plants in the large, cream, rectangular packet annotated " Levenhookia Sonderi, Mueller’s” have been selected as an appropriate lectotype. This material is comparable to that of K 000060054, MEL 1617989 and MEL 2256398-they are at the same flowering stage and bear white mycelia, presumably from being poorly dried following their collection-and showcases the distinctive, dark labellum, which Mueller notes on the label ("labellum atropurpureum!"). Material at TCD is also interpreted as being part of this gathering.

The remaining material on MEL 1617988 is not treated herein as type material. There is a blue, rectangular packet annotated " Coleostylis sonderi Portland" that contains a single flowering plant, which Mueller may have separated from MEL 2256407 to send to Bentham. There is a smaller blue packet annotated " Leeuwenhoekia sonderi " that contains flower fragments, but it is unclear to which gathering they belong. Finally, there are two packets containing seeds and withered corolla fragments that must be from a separate collection to that of the type gathering, which is not in fruit. It is unknown whether these seeds are from the type population or from a different locality or, indeed, two separate localities. It is of note that there are no fruiting specimens at MEL that predate the publication of this species and Mueller did not describe seed in the protologue. Seed is also inexplicably present in the packet attached to Portland’s flowering collection (MEL 2256407).

Notes.

Levenhookia sonderi is most likely to be confused with L. dubia , a species with which it can co-occur (there have been mixed collections made of the two (e.g. D.J. Van Bockel 195A and 195B, MEL; H.B. Williamson s.n., MEL 2256403). Their superficial similarity led Mildbraed (1908) to treat L. sonderi as a variety of L. dubia , but it was reinstated as a distinct species by Erickson (1958) on account of its dark red-purple labellum hood (cf. cream to yellow or pale pinkish red), green stems (cf. reddish) and shorter corolla tube (0.9-1.3 mm long and shorter than the longest calyx lobes cf. 1.5-3 mm long and ± equal to or longer than the calyx lobes). While stem colour cannot be used to reliably separate the two species, labellum colour and corolla tube length are informative and can be observed on pressed material. Levenhookia sonderi can be further separated from L. dubia by its unequal and obtuse or subacute calyx lobes (cf. equal and acute), hypanthium indumentum of both glandular and eglandular hairs (cf. glandular-hairy), linear-subulate basal appendanges on the labellum (cf. appendages lacking or rudimentary and rounded) and larger seed (0.6-1 mm long cf. 0.25-0.4 mm). It also tends to have more rounded leaf apices than L. dubia .

The column of L. sonderi appears to be adnate to the corolla tube like that of L. dubia , although this requires verification given the limited spirit material available for study. In one dissected flower, both stigmatic lobes were developed under the labellum hood with copious pollen observed. Like L. pusilla and L. murfetii , this suggests autogamy; L. sonderi is certainly akin to these two species, with all three sharing an indumentum of both eglandular and glandular hairs on the hypanthium.

Some individuals on the following collections of L. sonderi from South Australia and Victoria are infected by a smut that proliferates in the ovary, preventing the production of flowers and seed: R. Bates 32191 (AD); D. Hunt 2229 (AD); D. Hunt 2241 (AD, MEL); H.B. Williamson s.n. (MEL 2256399, MEL 275679).

Illustrations.

E.J. Raulings in N.G. Walsh & T.J. Entwisle, Fl. Victoria 4: 583, fig. 111b. 1999.

Selected specimens examined.

Australia. South Australia: [localities obfuscated for conservation reasons] N of Mt Gambier, 8 Nov 1964, D. Hunt 2229 (AD); N of Mt Gambier, 5 Dec 1964, D. Hunt 2241 (AD, MEL); Reedy Creek, 1 Oct 1998, D.E. Murfet 3317 (AD); Reedy Creek, 27 Oct 2011, D.E. Murfet 7404 (AD); [E of Nangwarry], 3 Nov 2013, D.E. Murfet 7624 (AD); Victoria: S of Crawford River, 20 Nov 1964, A.C. Beauglehole ALB 43334 (MEL); Dandenong Range, 20 Oct 1977, M.G. Corrick 5976 (MEL); Hawkesdale, Nov 1899, H.B. Williamson s.n. (MEL 2256403A); Warrandyte, 23 Oct 1983, J.Z. Yugovic s.n. (MEL).

Figures

Figure 3. Comparative distributions and floral morphologies A, B Levenhookia pusilla, with a disjunct distribution in Western Australia and South Australia and a dense inflorescence of pint-sized flowers (unvouchered, Mt Clarence, Albany, Western Australia) C, D L. murfetii, a Western Australian endemic with discrete markings at the base of the corolla lobes (J. A. Wege 1829) E, F L. sonderi, a rarity from South Australia and Victoria with red-purple markings on the labellum that are especially prominent in pressed material (unvouchered, from near St Andrews, Victoria). Photos by J. A. Wege (B), K. R. Thiele (D) and C. Lindorff (F). Scale bar on maps 1000 km.