Stenoglottis longifolia Hooker (1891

Phillips, Dean P. & Bytebier, Benny, 2020, A taxonomic revision of Stenoglottis (Orchideae, Orchidoideae, Orchidaceae), Phytotaxa 456 (3), pp. 219-243 : 231-232

2. Stenoglottis longifolia Hooker (1891 : t.7186). ( Figs 6–7 )

Type:— SOUTH AFRICA. KwaZulu-Natal: Ngoye Forest, date unknown (ex hort. 24 Sep 1889), Wood s.n. (holotype: K, 000415559!) .

Heterotypic synonyms: Stenoglottis molweniensis G.McDonald ex Shaw (2007: 24). Type:— SOUTH AFRICA. KwaZulu-Natal: unknown locality inland from Durban, date unknown (prior to May 1982), Stewart 2275 (holotype: WSY, 0100905, photo!) .

Stenoglottis molweniensis McDonald (2008: 12), nom. illeg. Type:— SOUTH AFRICA. KwaZulu-Natal: Durban, Krantzkloof Nature Reserve , close to Interpretive Centre , 420 m, 24 Feb 2002, Styles 657 (holotype: NU, 0015948!) .

Lithophytic or terrestrial. Leaves 7–15, lanceolate to linear, usually concolourous green or sparsely spotted, sometimes heavily spotted with brown or maroon, margins flat to weakly undulate, up to 21 × 3 cm. Inflorescence up to 80 cm tall, 20–120 flowers; sheaths spotted or unspotted. Bracts cordate to lanceolate, acute to acuminate, spotted or unspotted, recurved, always shorter than the ovaries, 7.0–17.0 × 2.5–4.5 mm. Flowers white, pink or lilac to mauve, often spotted with a darker shade of pink or purple on all parts; not self-pollinating. Sepals ovate, acute to obtuse, dorsal concave, laterals oblique, 4.5–7.6 × 2.8–5.4 mm, subequal. Petals ovate, oblique, acute, 3.5–6.3 × 2.5–4.6 mm. Labellum unspurred, oblong to obovate, 7.9–15.0 × 3.5–8.6 mm; side lobes usually with 2–5 fimbriae of variable length, sometimes ligulate and entire or shallowly incised; midlobe acute to attenuate, longer than or subequal to side lobes. Column up to 2 mm long; stigmatic arms suberect or parallel to labellum in mature flowers, curving outward; auricles large, clavate, up to 0.8 mm × 0.6 mm at the apex, projecting beyond the anther between the pollinia and stigmas. Ovary 8–22 mm long.

Diagnostic characters:— Stenoglottis longifolia is most likely to be mistaken for S. fimbriata . Both species exhibit a high degree of morphological variation, particularly in those characters that have historically been used to diagnose them, including overall plant size and degree of fimbriation of the labellum. Whereas specimens of S. longifolia are generally more robust (i.e. having long leaves and tall, many-flowered inflorescences) and usually have relatively large individual flowers with deeply divided side lobes, these traits are inconsistent and vary considerably within and between populations of both taxa. Instead, S. longifolia and S. fimbriata are most reliably distinguished by differences in their floral bracts, column morphology and pollination mode. The bracts of S. longifolia flowers are markedly recurved ( Fig. 6I, L ), whereas those of S. fimbriata are sheathing. The auricles of S. longifolia are clavate with narrow stalks and swollen apices and project beyond the anther, such that they lie between the stigmatic arms and pollinia ( Fig. 6N–O ). In contrast, the auricles of S. fimbriata are usually slender or wider only slightly at the apex and are adnate to the sides of the anther and therefore do not obstruct the stigmatic arms ( Figs 2 , 4F–G ). Consequently, the flowers of S. fimbriata (both varieties) exhibit a high incidence of spontaneous self-pollination, whereas those of S. longifolia do not.

The floral morphology of S. longifolia is similar in most respects to S. inandensis , but they can be easily distinguished by the spurred labellum of the latter. Likewise, S. longifolia is not likely to be confused with either S. woodii or S. macloughlinii due to their spurred labella.

Notes:— Stenoglottis molweniensis was first used informally by McDonald (2006), who proposed it in reference to plants observed in the Molweni River Valley and Noodsberg areas of KwaZulu-Natal; he described them as resembling S. woodii but lacking a spur. The name was formalised by Shaw (2007), who designated a specimen prepared from material cultivated at the Royal Horticultural Society Garden at Wisley, UK, as the holotype. This specimen, Stewart 2275, was “collected by a student of Joyce Stewart’s from an unknown locality inland from Durban, KwaZulu-Natal, South Africa, prior to May 1982 ”. This is almost certainly the plant referred to by Stewart (1989), under the ‘hybrids’ section of her review of Stenoglottis , as having been given to her by a student “who could not recall its provenance exactly”. She described this plant, together with specimens observed in the Noodsberg area, as “intermediate in character between those of S. longifolia and S. woodii ”, having foliage similar to that of S. woodii but with “broad side lobes of the lip [that] are finely fringed, though the fimbriae are not as long as those of S. longifolia , and the lip has no spur”.

The validation of S. molweniensis by Shaw (2007) was done apparently without the knowledge of McDonald, who a year later attempted to formalise his earlier proposed name, designating a specimen (Styles 657) collected from the Krantzkloof Nature Reserve in the Molweni River Valley as the holotype ( McDonald 2008). Specimens collected from both the Noodsberg area (Phillips 26 and Phillips 56) and Molweni River Valley (Phillips 16 and Phillips 38) were included in the phylogenetic analysis of Phillips & Bytebier (2020). These populations were not resolved as a clade; instead, the Noodsberg specimens (referred therein as S. cf. longifolia ) were found to have ITS and ETS sequences identical to those of S. longifolia from the Kranskop area of KwaZulu-Natal (Phillips 27), with which they were collectively resolved as sister to S. longifolia from Eshowe and Ngoye Forest, the latter being the type locality of S. longifolia . Based on the remarks of Stewart (1989) and Shaw (2007), as well as comparison of the type material with specimens personally collected during this study, it is almost certain that the holotype of S. molweniensis G. McDonald ex J.M.H.Shaw originated from the Noodsberg area rather than the Molweni River valley, in which case S. molweniensis G. McDonald ex J.M.H.Shaw is nested within S. longifolia .

Regardless of any issues surrounding its nomenclature and typification, the concept of S. molweniensis cannot in any case be reliably distinguished from S. longifolia based on the information provided by Shaw’s description, which diagnoses it on the basis of its leaves (being entire and non-undulating) and side lobes (having fimbriae shorter than those of S. longifolia ). Likewise, the characters provided in the morphological key accompanying McDonald’s concept (number and density of flowers, robustness of the plants and colouration of sepals and petals) are not adequate for distinguishing these taxa. Recent morphological investigations, including a multivariate morphometric analysis of specimens sampled from across the range of localities in South Africa also do not discriminate between S. longifolia and S. molweniensis or reveal additional qualitative characters for separating them ( Phillips & Bytebier 2020). In contrast, several shared characteristics (spurless labella, recurved bracts, clavate auricles and flowers that never self-pollinate) collectively distinguish these populations from the remaining Stenoglottis taxa. Furthermore, there is no indication from nuclear DNA data, or incongruence of nuclear and plastid markers, that the specimens previously referred to as S. molweniensis are of hybrid origin. Consequently, S. molweniensis is synonymised here with S. longifolia .

Distribution and ecology: — Stenoglottis longifolia occurs in KwaZulu-Natal, South Africa, and the Lebombo Mountains of Eswatini and southern Mozambique ( Fig. 7 ) at elevations of 230–1200 m. It has also previously been reported to occur in the Eastern Cape by Linder & Kurzweil (1999). However, the specimen they referred to (Pegler 1902, cited here as Pegler s.n. collected March 1902) is confirmed as S. fimbriata var. fimbriata . No other herbarium specimens from the Eastern Cape or plants found during fieldwork in the province were identified as S. longifolia . Stenoglottis longifolia occurs in forests or forest margins in deep or partial shade, most commonly as a lithophyte on boulders, frequently along streams or on south-facing cliff faces; occasionally it occurs as a terrestrial on banks or the forest floor. It flowers February–July and is not self-pollinating.

Specimens:— ESWATINI. Lubombo Region: 2631 (Mbabane): Siteki [Stegi] (– BD) , unknown collector NBG191/62 ( BOL 49915!) . MOZAMBIQUE. Maputo Province: 2531 (Komatipoort): Namaacha District, Lebombo Mountains [Libombos], Mount M’ponduine [Mpondium], 800 m (– DD) , 22 Feb 1955, Exell et al. 514 ( BM000034604 !) ; Namaacha District, Mount M’ponduine [Monte Ponduine], 800 m (– DD) , 17 Mar 1969, Correia & Marques 617 ( WAG1140770 photo!); Namaacha District, Mount M’ponduine [Monte Ponduine], 800 m (– DD) , 31 Mar 1975, Marques 2679 ( WAG1140771 photo!) . SOUTH AFRICA. KwaZulu-Natal: 2731 (Louwsberg): Ithala Nature Reserve (– CA) , Mar 1990, Scott-Shaw 3266 ( CPF0021092 !) . 2830 (Dundee): Kranskop, 10 miles north of Tugela River on Kranskop–Nkandla Road (– DD) , Mar 1956, Bell 27 ( BOL 49895!) ; Kranskop, The Kop (– DD) , Feb 1949, Gibbs 48 ( NU0010073 !) ; Kranskop , 1158 m (– DD) , 9 Mar 1962, Mauve 4204 ( PRE0036821 -0!); Kranskop, on rocks next to road through Kranskop Forest , 825 m (– DD) , 15 Mar 2016 (ex hort. Mar 2018), Phillips 27 ( BNRH!, NU0088332 !) ; Kranskop, Untunjambili Forest (– DD) , 1 Apr 1943, West 1984 ( NH0034084 -0!). 2831 (Nkandla): Hlabisa, Hluhluwe Game Reserve , 609 m (– BB) , 28 Mar 1954, Ward 2261 ( CPF0021098 !, NH0042082 -0!, NH0042226-0!, PRE0036853 - 0!); Nkandla, 20 miles from Nkandla village to Eshowe (– CA) , date unknown, Bell 43 ( BOL 49894!) ; Nkandla Forest , 1158 m (– CA) , 29 Feb 1952, Codd 6975 ( BR0000021817861 photo!, K001208119 !, MO, NH0041245-0!, NU0010098!, P00339728 photo!, PRE0036816-0!, UC, US) ; Nkandla, upper edge of Nkandla Forest , 1219 m (– CA) , 15 Feb 1961, Edwards 2483 ( NU0010099 !) ; Nkandla, Dolwane Store (– CA) , Mar 1964, Hilliard s.n. ( BOL 49907!) ; Nkandla Forest (– CA) , date unknown, Moberley s.n. ( NU0010097 !) ; Nkandla Forest Reserve , 1196 m (– CA) , 8 Apr 2016 (ex hort. Mar 2018), Phillips & Potgieter 35 ( BNRH!, NU0088344 !, NU0088345 !) ; Eshowe, Mlalazi River north of Eshowe , 420 m (– CD) , 31 Mar 2016 (ex hort. Apr 2018), Phillips & Potgieter 33 ( BNRH!, NU0088341 !, NU0088342 !) ; Eshowe (– CD) , 25 Jul 1892, Saunders 2 ( K001208120 !) ; Eshowe, on stones in river bed near Eshowe (– CD) , Apr 1944, Schelpe s.n. ( NU0010105 !) ; Ngoye Forest Reserve, The Dome , 450 m (– DC) , 16 Jun 1982, Balkwill 304 ( NU0010107 !) ; Ngoye Forest Reserve, The Dome , 480 m (– DC) , 30 Mar 1984, Balkwill et al. 1330 ( NU0010106 !) ; Ngoye Forest (– DC) , Apr 1999, Edwards & Potgieter 1645 ( NU0010104 !) ; Ngoye Forest Reserve , 487 m (– DC) , 8 Feb 1963, Huntley 262 ( MO!) ; Ngoye Forest Reserve , 230 m (– DC) , 12 Mar 1993, Hutchings 3216 ( NH0116221 -0!); Ngoye Forest Reserve , path leading off old woodcutter’s road to junction of streams (– DC) , 8 Mar 1993, Hutchings 3217 ( NH0116198 -0!); Ngoye Forest Reserve , 300 m (– DC) , 5 May 1993, Hutchings 3230 ( NH0116207 -0!, PRE0789692 - 0!); Ngoye Forest Reserve , 300 m (– DC) , 5 May 1993, Hutchings 3231 ( PRE0789691 -0!); Ngoye Forest Reserve, near Birder’s Camp , 286 m (– DC) , 31 Mar 2016 (ex hort. Apr 2018), Phillips & Potgieter 31 ( BNRH!, NU0088337 !, NU0088338 !) ; Ngoye Forest Reserve, north of Birder’s Camp , 351 m (– DC) , 31 Mar 2016 (ex hort. Apr 2018), Phillips & Potgieter 32 ( BNRH!, NU0088339 !, NU0088340 !) ; Ngoye Forest (– DC) , Jun 1960, Schelpe s.n. ( BOL 49910!) ; Ngoye Forest Reserve , 240 m (– DC) , 23 Apr 1987, Ward 2033 ( NH0101107 -0!); Ngoye Forest (– DC) , 21 Feb 1961, Wells & Edwards 114 ( NU0010101 !) ; Ngoye Forest [Ngoya], 609 m (– DC) , 1 Apr 1899, Wood 7502 ( MO!) ; Ngoye Forest [Ungoya], 304 m (– DC) , May 1887, Wood 1024 ( BOL 50016!, P00339735 photo!); Ngoye Forest [Ungoya], (– DC) , 16 Apr 1895, Wood 5650 ( BOL 49917!, NH0007116-1 !, PRE0036850 !) ; Ngoye Forest [Ungoya], 304 m (– DC) , 10 May 1887, Wood s.n. ( BM001172120 !) . 2930 (Pietermaritzburg): Noodsberg, Marchmont Farm , 825 m (– BD) , 10 Mar 2016 (ex hort. Mar 2018), Phillips 26 ( BNRH!, NU0088331 !) ; Noodsberg, Marchmont Farm , 861 m (– BD) , 3 Apr 2017, Phillips 56 ( NU0088391 !) ; Inanda Heights (– DB) , 25 Mar 1940, Schweickerdt 1430 ( NH0031898 -0!); Inanda (– DB) , May 1880, Wood 548 ( BM001172054 !, K001208133 !) ; Shongweni , 538 m (– DC) , 26 Nov 2016 (ex hort. Mar 2018), Phillips 38 ( BNRH!, NU0088348 !) ; Kloof, Forest Hills , 609 m (– DD) , 5 Apr 1964, Hilliard 2821 ( NU0010079 !) ; Krantzkloof Nature Reserve , 472 m (– DD) , 13 Feb 2016 (ex hort. Apr 2018), Phillips & Garnier 16 ( BNRH!, NU0088323 !) . Without precise locality: Zululand, Apr 1902, Wylie s.n. ( P00339727 photo!); Zululand , Mar 1903, Wylie s.n. ( L1526645 photo!) .

Figures

FIGURE 2. Selected specimens of Stenoglottis fimbriata var. fimbriata. A, column lateral view, Oribi Gorge Nature Reserve (KZN). B–C, column lateral and ventral view, Msikaba (EC). D, column lateral view, Nkandla Forest Reserve (KZN). E–F, column lateral and ventral view, Kaapschehoop (MP). Scale bars = 0.5 mm. Abbreviations: au = auricle, an = anther, stg = stigmatic arm.

FIGURE 4. Selected specimens of Stenoglottis fimbriata var. modesta. A, inflorescence, Fawn Leas (KZN). B, flowers ventral view, Mnyolo (EC). C, habit (in situ), Vryheid Hill Nature Reserve (KZN). D–E, flowers ventral and lateral view (showing vestigial spur and sheathing bract), Vryheid Hill Nature Reserve (KZN). F–G, column ventral and lateral view, Ixopo (KZN). Scale bars = 5 mm (A–B, D– E), 0.5 mm (F–G).Abbreviations: au = auricle, an = anther, stg = stigmatic arm. C reproduced with the permission of Herbert Stärker.

FIGURE 6. Selected specimens of Stenoglottis longifolia. A, flower ventral view, Nkandla Forest Reserve (KZN). B, flowers, Ngoye Forest Reserve (KZN). C–D, flower ventral view and inflorescence, Eshowe (KZN). E, flower ventral view, Krantzkloof Nature Reserve (KZN). F, flower ventral view, Shongweni (KZN). G, flowers, Noodsberg (KZN). H–J, flower ventral view, lateral view (showing spurless labellum and recurved bract) and leaf rosette (cultivated), Kranskop (KZN). K–L, flower ventral and lateral view, Ngoye Forest Reserve (KZN). M, habit (in situ), Eshowe (KZN). N–O, column lateral and ventral view, Ngoye Forest Reserve (KZN). Scale bars = 5 mm (A–L), 0.5 mm (N–O). Abbreviations: au = auricle, an = anther, stg = stigmatic arm. M reproduced with the permission of Herbert Stärker.

FIGURE 7. Distribution of Stenoglottis longifolia.