Swainsona 35: 11–22 (2021) © 2021 Board of the Botanic Gardens & State Herbarium (Adelaide, South Australia) The other ‘propeller plant’ – Notes on Stenanthemum Reissek (Rhamnaceae: Pomaderreae) and a key to the genus in Australia Jürgen Kellermanna,b & Kevin R. Thielec a State Herbarium of South Australia, Botanic Gardens and State Herbarium, Hackney Road, Adelaide, South Australia 5000 Email: [email protected] b The University of Adelaide, School of Biological Sciences, Adelaide, South Australia 5005 c School of Biological Sciences, University of Western Australia, 35 Stirling Hwy, Crawley (Perth), Western Australia 6009 Email: [email protected] Abstract: Descriptions are provided for ten taxa of Stenanthemum Reissek published in the 19th century and their typification is clarified. Lectotypes are chosen for St. divaricatum (Benth.) Rye, St. humile Benth., St. leucophractum (Schltdl.) Reissek, St. pimeleoides (Hook.f.) Benth., St. pumilum (F.Muell.) Diels and Cryptandra subgen. Solenandra Reissek (a synonym of Stenanthemum). A key to all species and subspecies of the genus, which is endemic in Australia, is provided. Keywords: Nomenclature, typification, identification key, Rhamnaceae, Pomaderreae, Stenanthemum, Australia Introduction The concept of Hooker (1862) and Bentham (1863) was generally followed by subsequent authors, but Stenanthemum Reissek contains c. 30 species, most Mueller (1875) still included the genus in Spyridium endemic to Western Australia (Rye 1995, 2001, 2007), when describing Sp. pumilum F.Muell., a species that but eight species occur in other States, as outlined in Diels & Pritzl (1904) transferred to Stenanthemum as Thiele (2007). The taxonomic history of the genus was St. pumilum (F.Muell) Diels. discussed in Kellermann (2007) and Thiele (2007). From the early years of the 20th century, Stenanthemum The genus was described by Reissek (1858), who was not accepted any more by Australian botanists, included four species that were previously published in with the species mostly subsumed under Cryptandra Cryptandra Sm.: St. leucophractum (Schltdl.) Reissek, and Spyridium (e.g. Black 1926, 1952; Gardner 1931; St. pomaderroides (Reissek) Reissek, St. coronatum Suessenguth 1953; Blackall & Grieve 1956; Curtis 1956; (Reissek) Reissek and St. tridentatum (Steud.) Reissek. Willis 1973; Conn 1983; Canning & Jessop 1986). The latter three were originally grouped in Cryptandra There was also a hiatus in the description of new species. sect. Solenandra Reissek (1848). In subsequent years, Rye (1995), in a re-evaluation of all genera of however, Stenanthemum was not accepted by Ferdinand Rhamnaceae in Western Australia, re-instated von Mueller, who included it in Spyridium Fenzl Stenanthemum and described 21 new species and (Mueller 1862) or Cryptandra (Mueller 1875, 1882). subspecies (Rye 1995, 2001, 2007). Bean (2004) published a new species from Queensland, St. argenteum Hooker (1862) recognised the genus, albeit with a A.R.Bean. Thiele (2007) clarified the generic limits different circumscription, excluding species with a between Spyridium, Cryptandra and Stenanthemum, shorter floral tube; Bentham (1863) listed these short- reviewed all species occurring outside Western Australia, tubed taxa under Spyridium in the Flora Australiensis, and described two new species. as Sp. tridentatum (Steud.) Benth., Sp. divaricatum Benth. and Sp. complicatum F.Muell. In addition to While Rye (1995, 2001, 2007) provided detailed the first three Stenanthemum species of Reissek (1858) descriptions of all her new taxa, she did not give mentioned in the previous paragraph, Bentham’s (1863) descriptions for already existing species. Thiele treatment of Stenanthemum also included St. pimeleoides (2007) provided descriptions of two of these species, (Hook.f.) Benth., St. humile Benth. and St. waterhousei St. leucophractum and St. pimeleoides. A key to species (F.Muell.) Benth. However, the latter species is actually in Western Australia was published by Rye (2007) and a a species of Spyridium Fenzl. (Kellermann 2007). key for the rest of Australia by Thiele (2007). Published online: 7 April 2021 • flora.sa.gov.au/swainsona ISSN 2206-1649 (Print) • ISSN 2206-1657 (Online) J. Kellermann & K.R. Thiele Swainsona 35 (2021) Rye (2001, 2007) also described an unusual taxon, (1903). — Lectotype (here designated): Cryptandra St. sublineare Rye, which does not fully agree with pomaderroides Reissek. Stenanthemum pomaderroides the generic circumscription of Stenanthemum. The (Reissek) Reissek. ≡ question as to whether this taxon should be separated into another genus, in view of a few unique characters Note. Hooker (1855) segregated the only species of noted by her, or remain in Stenanthemum, is the subject Stenanthemum in Tasmania (Tas.), described by him of current research. as C. pimeleoides Hook.f., in a separate section of Cryptandra, i.e. sect. Stenocodon Hook.f. In this paper, ten taxa of Stenanthemum, first published in the 19th century, are typified and provided with Kuntze (1891) published the superfluous Solenandra to modern descriptions based on available material. replace Stenanthemum, since he was of the opinion that A combined key for the whole of Australia is also Cryptandra subgen. Solenandra Reissek should have presented here; this is also available on KeyBase retained its name when Reissek raised it to generic rank. (https://keybase.rbg.vic.gov.au/). Note that authorities By doing this, however, Kuntze created an illegitimate for the taxa in the key can be found in APNI (2020). name due to the presence of the earlier homonym Solenandra Hook.f. (Rubiaceae). McNeill (2014) clarified some misconceptions about holotypes and procedures for lectotypification, and Typification. Reissek (1848) included three species in his advice is followed in this paper. All type specimens Cryptandra subgen. Solenandra, all of which are now have been examined; those that were seen online via in Stenanthemum: St. pomaderroides, St. coronatum JSTOR Global Plants and other websites are indicated and St. tridentatum. The first of these is designated as by “photo seen”. Rye (1995) mentions some types for the lectotype. It has a glabrous ovary summit, as well previously published species. This can be regarded as as an inconspicuous floral disc, both of which are the inadvertent typification, and her use of the term “type” defining characters of Reissek’s subgenus. or “holotype” is corrected to “lectotype” (Art. 9.10; Turland et al. 2018) in the species treatments below. 1. Stenanthemum complicatum (F.Muell.) Rye This correction is possible, as before 2001 it was not Nuytsia 10: 282 (1995). — Spyridium complicatum necessary to use the phrase “here designated” when F.Muell., Fragm. 3: 78 (1862). — Cryptandra lectotypifying names (Art. 7.11). complicata (F.Muell.) F.Muell., Syst. Census Austral. Pl. 61 (1883). — Type citation: ”In planitiebus arenosis The common name ‘propeller plant’ is applied to two apud fodinas Geraldinae ad flumen Murchsion. species of Australian Rhamnaceae: the more widespread Old field.” — Lectotype: Sand plain, nr Yanarie Spyridium vexilliferum (Hook.) Reissek from Tasmania, / Murchison River, W.A., s.d., A.F. Oldfield s.n. Victoria and South Australia (also called ‘helicopter (MEL90946), fide Rye, Nuytsia 10: 282 (1995), as bush’ and ‘winged spyridium’), and to Stenanthemum “holo”. Isolectotype: Murchison River, A.F. Oldfield pimeleoides, endemic to Tasmania (which is also called s.n. (K001096741, Herb. F.Mueller, ex Herb. Hooker). ‘spreading stenanthemum’). In both cases the common name refers to the propeller-like white felty floral leaves Illustrations: B.J. Grieve, How to Know W. Austral. that surround the inflorescence (Wapstra et al. 2010). Wildfl. (2nd edn) 2: 597 (1998). Woody, straggling shrub to 2 m high, with densely Nomenclature rusty-pubescent young stems. Leaves: stipules broadly triangular, 1–3 mm long, free or shortly connate; Stenanthemum Reissek petiole 1–5 mm long; lamina broadly obovate, (6–) Linnaea 29: 295 (1858). — Spyridium sect. 8–12 (–15) mm long, 4–8 mm wide, cuneate at base, Stenanthemum (Reissek) F.Muell., Fragm. 3: 77 flat or folded, apex obtuse to acute and recurved- (1863), nom. inval. — Cryptandra sect. Stenanthemum apiculate, greyish-velvety above with short erect simple (Reissek) F.Muell., Fragm. 3: 77 (1862). Suess., Nat. hairs, densely greyish- or rusty-villous or pubescent Pflanzenfam. (2nd edn) 20d: 118 (1953). — Type: beneath. Inflorescences to 1 cm wide, with 10–50 Stenanthemum leucophractum (Schltdl.) Reissek, fide flowers. Flowers densely white-woolly; free hypanthium Rye, Nuytsia 13: 496 (2001). tube 0.6–0.8 mm long, 0.8–1.5 mm diameter. Sepals Cryptandra sect. Stenocodon Hook.f., Bot. Antarct. Voy 0.9–1.2 mm long. Petals 0.6–0.7 mm long, distinctly III (Fl. Tasman.) 1: 75 (1855). — Type: Cryptandra clawed. Disc inconspicuous. Ovary roof stellate-hairy; pimeleoides Hook.f. Stenanthemum pimeleoides style 0.8–1.1 mm long. Fruits 2.5–3 mm long; seeds (Hook.f.) Reissek. (typification≡ by monotypy). 1.5–1.7 mm long. Cryptandra subgen. Solenandra Reissek in Lehm., Pl. Preiss. 2: 288 (1848). — Solenandra (Reissek) Kuntze, Distribution. Endemic to south-western Western Revis. Gen. Pl. 1: 120 (1891), nom. illeg., nom. superfl., Australia (W.A.), between Shark Bay and Mullewa, in non Hook.f. in Benth. & Hook.f., Gen. Pl. 2: 12, 43 shrublands and woodland on sand. (1873) (Rubiaceae). — Cryptandra sect. Solenandra (Reissek) T.Post & Kuntze, Lex. Gen. Phan. 150 Phenology. Flowers