Stenoglottis woodii Schlechter (1924: 242)

Phillips, Dean P. & Bytebier, Benny, 2020, A taxonomic revision of Stenoglottis (Orchideae, Orchidoideae, Orchidaceae), Phytotaxa 456 (3), pp. 219-243 : 237

5. Stenoglottis woodii Schlechter (1924: 242) . ( Figs 10–11 )

Type:— SOUTH AFRICA. KwaZulu-Natal: Botha’s Hill , 762 m, 9 Feb 1898, Wood 6697 (holotype: B, destroyed; isotype: NH) .

Lithophytic or terrestrial. Leave s 6–12, broadly lanceolate to oblanceolate, unspotted, concolourous green, margins flat, entire, up to 14.5 × 3.5 cm. Inflorescence up to 50 cm tall with 15–65 flowers; sheaths unspotted. Bracts lanceolate, acute to acuminate, unspotted, sheathing, always shorter than the ovaries, 6.0–15.0 × 2.5–5.0 mm. Flowers white to pale pink, often spotted with a darker shade of pink or purple on the labellum only; not self-pollinating. Sepals ovate to narrowly ovate or elliptic, acute to obtuse, dorsal concave, laterals oblique 3.7–6.2 × 2.0– 3.6 mm, laterals slightly longer. Petals ovate, oblique, acute, 3.2–4.8 × 2.3–3.4 mm. Labellum spurred, broadly obovate to cuneate in outline, 7–12 × 4.8–8.4 mm; side lobes broad, truncate or rounded, margins usually entire, rarely shallowly incised; midlobe narrower than side lobes, obtuse to acute, subequal or slightly longer than side lobes; spur short and straight, subsaccate, 0.4–1.5 mm × 0.4–0.7 mm at the apex, without nectar. Column up to 2.0 mm long; stigmatic arms parallel to labellum in mature flowers, curving outward; auricles large, clavate, up to 0.8 mm × 0.5 mm at the apex, projecting beyond the anther between the pollinia and stigmas. Ovary 10.5–18.5 mm long.

Diagnostic characters:— Stenoglottis woodii is not likely to be confused with S. fimbriata or S. longifolia due to its spurred labellum ( Fig. 10B, I ), broad side lobes ( Fig. 10A, C–H ) and entire, unspotted leaves ( Fig. 10J ). It may be mistaken for S. inandensis , for which a detailed diagnosis is provided in the notes for that species. Stenoglottis woodii is most closely related and morphologically similar to S. macloughlinii . They are, however, easily distinguished by differences in their floral spurs: S. woodii has short (0.4–1.5 mm), straight, sub-saccate, nectar-less spurs, whereas those of S. macloughlinii are longer (2.0–3.0 mm), usually curved, tapering and nectar-producing. The side lobes of S. woodii are rounded to truncate, and the apex of the midlobe is acute to obtuse; in S. macloughlinii all lobes tend to be wider and rounder than those of S. woodii . Stenoglottis woodii also flowers later than S. macloughlinii and has a more northeastern distribution ( Fig. 11 ).

Notes:— Some populations that have historically been regarded as S. woodii have been excluded from the revised circumscription presented here. These are discussed either with S. inandensis or under putative hybrids at the end of the taxonomic treatment. With these removed, the morphological boundary between S. woodii and S. macloughlinii becomes distinct. Nevertheless, these species are clearly closely related; accessions included in the phylogenetic analysis of nuclear DNA markers ( Phillips & Bytebier 2020) were resolved as a polytomy of intermixed specimens with essentially identical ITS and ETS sequences and can only be phylogenetically distinguished by their plastid DNA. This incongruence suggests that S. woodii may have originated by introgressive hybridisation of S. macloughlinii and one of the spurless species (or recent ancestors of these taxa).

Distribution and ecology:— Stenoglottis woodii is restricted to KwaZulu-Natal, where it occurs in the Highflats area near Ixopo and at several localities near Durban and Pietermaritzburg ( Fig. 11 ) at elevations of 600–1000 m. It tends to prefer somewhat drier and more exposed conditions than S. fimbriata , S. longifolia and S. inandensis . It occurs most commonly in partial shade on forest margins along the tops of south-facing cliffs, occasionally in grassland in full sun on rocky outcrops adjacent to forest patches or forested gorges as a lithophyte or terrestrial in shallow soil. These habitat preferences are not obligate, however, because the plants also occur less frequently in deep shade on boulders in forests. It flowers December–March and is not self-pollinating.

Specimens examined:— SOUTH AFRICA. KwaZulu-Natal: 2930 (Pietermaritzburg): New Hanover, Little Noodsberg , 1067 m (– BD) , 12 Feb 1982, Hilliard & Burtt 15495 ( E, NU0010111 !) ; Ingomankulu , ± 5 km SW of Camperdown, 970 m (– CD) , 11 Jan 2016 (ex hort. Jan 2018), Young & Phillips 2474 ( NU0088298 !) ; Ingomankulu , ± 5 km SW of Camperdown, 976 m (– CD) , 11 Jan 2016, Young & Phillips 2475 ( NU0088299 !) ; Ingomankulu , ± 5 km SW of Camperdown, 975 m (– CD) , 11 Jan 2016 (ex hort. Jan 2018), Young & Phillips 2476 ( NU0088300 !) ; Inchanga, Drummond Mountain , 823 m (– DA) , 22 Mar 1952, Cooke s.n. ( BOL 49911!) ; Inchanga , 609 m, (– DA) , 31 Mar 1957, Loubser 46a ( NU0010075 !) ; Cumberland Nature Reserve , in forested gorge near base of small waterfall, 612 m (– DA) , 17 Feb 2016 (ex hort. Mar 2018), Phillips 19 ( NU0088326 !) ; Monteseel , 739 m (– DA) , 24 Mar 2016 (ex hort. Mar 2018), Phillips 30 ( BNRH!, NU0088336 !) ; Inanda (– DB) , 25 Sep 1963, Strey 5572 ( NH0052666 -0!); Ndwedwe, Nhlangakazi Mountain , 800 m, (– DB) 7 Feb 2016, Styles 5269 ( NH0141063 -0!); Inanda Mountain , 690 m (– DB) , 19 Jan 2016 (ex hort. Jan 2018), Young et al. 2513 ( BNRH!, NU0088306 !, NU0088307 !) ; Botha’s Hill, Kearsney College (– DC) , 15 Mar 1964, Hilliard 2808 ( NU0010114 !) ; Botha’s Hill, Kearsney College (– DC) , 15 Mar 1964, Hilliard s.n. ( BOL 49908!) ; Durban, Key Ridge (– DC) , 10 Feb 2002, Styles D.G.A. 500 ( NU0015949 !) ; Botha’s Hill (– DC) , 15 Mar 1901, Wood 8224 ( P00339734 photo!); Pinetown, Fields Hill (– DD) , Apr 1983, Edwards 52 ( NU0010110 !) ; Pinetown, Fields Hill , 484 m (– DD) , 30 Jan 2019, Phillips 91 ( NU0088393 !) . 3030 (Port Shepstone): Ixopo, Highflats (– AC) , Jan 1928, Grant s.n. ( BR0000021817885 photo!); Ixopo, Highflats (– AC) , Jan 1928, Grant s.n. ( MO!) ; Ixopo, Highflats , 870 m (– AC) , 22 Jan 2016 (ex hort. Jan 2018), Phillips & Doarsamy 3 ( BNRH!, NU0088309 !, NU0088310!, NU0088311 !); Ixopo, Highflats , 870 m (– AC) , 22 Jan 2016 (ex hort. Jan 2018), Phillips & Doarsamy 4 ( BNRH!, NU0088312 !, NU0088313 !) .

Figures

FIGURE 10. Selected specimens of Stenoglottis woodii. A–C, flower ventral view, spur clos-up and inflorescence, Monteseel (KZN). D, flower ventral view, Ingomankulu (KZN). E–G, flower ventral views (showing morphological variation in population), Highflats (KZN). H–I, flower ventral and lateral view (showing spurred labellum and sheathing bract), Fields Hill (KZN). J, leaf rosette (cultivated), Ingomankulu (KZN). K–L, column lateral and ventral view, Highflats (KZN). Scale bars = 5 mm (A, C–I), 2 mm (B); 0.5 mm (K–L). Abbreviations: au = auricle, an = anther, stg = stigmatic arm.

FIGURE 11. Distribution of Stenoglottis woodii (white) and S. macloughlinii (black).