Eulophia edwardii Bytebier, 2023

Bytebier, Benny, 2023, Eulophia edwardii (Orchidaceae), a new species from the Pondoland Centre of Endemism in South Africa, Plant Ecology and Evolution 156 (3), pp. 326-332 : 326

Eulophia edwardii Bytebier sp. nov.

Figs 1 , 2 , 3

Type.

SOUTH AFRICA - KwaZulu-Natal • Port Edward, Rennies Beach ; 31°04'S, 30°12'E; 15 m; 8 Feb. 2015; fl.; B. Bytebier, K.W. Grieve & G.R.H. Grieve 3501; holotype: NU [NU0094001]; isotypes: BR, NH, NU [NU0094003] .

Diagnosis.

Eulophia edwardii is morphologically most similar to E. macowanii , but differs from E. macowanii by having fully resupinate flowers at anthesis vs non-resupinate in E. macowanii , by having white petals vs creamy-yellow petals; and by having papery, overlapping sheaths on the peduncle vs more sturdy, non-overlapping sheaths or occasionally the tip of one sheath only just reaching the bottom of the next one. It differs from E. ovalis by having spreading petals instead of petals that cover the column and are bent over the lip.

Description.

Terrestrial herb, 220-325 mm tall. Perennating organs subterranean, forming a beaded rhizome up to 110 mm long with up to 7 globose to ovoid tuberous units, each 15-20 mm in diameter and 10-17 mm tall, covered with fibrous remains of leaf bases; roots white, up to 170 mm long × 3-5 mm wide. Leaves 5-9, fully developed at anthesis, arranged in an arcuate fan, plicate, linear to linear-lanceolate, acute, the uppermost up to 270 mm long × 20 mm wide, the lowermost 2-3 much smaller and dry at anthesis. Inflorescence erect, lax to subdense, 5-14-flowered; peduncle slender, 2-3 mm in diameter, covered with 6-8 papery, overlapping sheaths, up to 115 mm long × 14 mm wide; rachis 30-50 mm with papery, lanceolate to elliptic, acuminate bracts 15-17 mm long × 5-9 mm wide, slightly shorter than the ovary. Flowers fully resupinate at anthesis, sepals brownish green to green, petals and lip white, papillae pale yellow, spur greenish to greenish brown. Sepals spreading; median sepal 19-22 mm long × 6-7 mm wide, apex acute to attenuate; lateral sepals 23-25 mm long × 7-9 mm wide, apex acute to attenuate. Petals spreading, 21-25 mm long × 10-14 mm wide, ovate to elliptic, apex obtuse to rounded. Lip 3-lobed, 19-21 mm long × 20-24 mm wide; side lobes elliptic to obovate, 12 mm long × 6 mm wide; midlobe orbicular with 3 undulate ridges in basal third and 3 tomentose veins on either side of the ridges, ridges passing into relatively few, long, slender, branched papillae ending abruptly midway along the lip. Spur 5 mm, conical to cylindrical, slightly dorsoventrally flattened, incurved and often slightly bifid at apex. Column 5-6 mm. Anther cap 1.5-2 mm wide, beaked. Pollinia 2 attached to stipe of 1 mm. Ovary 19-29 mm long. Fruit ellipsoidal, pendent.

Distribution.

Only known from the type locality (Fig. 3 ).

Habitat and ecology.

Growing in moist, hygrophilous, lightly sloping, windswept, species-rich coastal grassland, dotted with clumps of Strelitzia nicolai Regel & Körn. CREW (Custodians of Rare and Endangered Wildflowers) Pondoland members have documented more than 370 species of indigenous angiosperms on this piece of land, including 16 other orchid species (Kate Grieve and Graham Grieve pers. comm.).

Phenology.

Flowering in February (end of summer).

Etymology.

Named in honour of Edward (Ted) George Hudson Oliver for his lifelong dedication to botany, particularly the study of Ericaceae and Orchidaceae . Indirectly, it also refers to Port Edward, so far, the only place where this taxon is known to occur.

Preliminary IUCN conservation assessment.

Critically Endangered: CR B2ab(i,ii,iii). As far as can be judged from repeated monitoring by the author and the CREW Pondoland team, the subpopulation is stable, and although the number of flowering individuals (the only possible way of counting the individual plants) changes from year to year, the maximum number of flowering specimens has never been more than an estimated 200. These occur in one subpopulation spread out over an area of about one hectare (B2a). CREW Pondoland has surveyed the very few remaining patches of coastal grassland near Port Edward in KwaZulu-Natal, as well as several along the Eastern Cape Pondoland coast. Despite numerous efforts, no additional subpopulations have so far been traced. A decline in the extent of occurrence (B2bi), area of occupancy (B2bii), and extent and quality of habitat (B2biii) is inferred in view of the fact that north of the Mtamvuna river (as far north as Durban, which is well beyond the limits of the Pondoland Center of Endemism) almost no untransformed grasslands close to the sea and matching the type locality still exist. North of Durban, coastal grasslands in proximity to the highwater mark do not exist until near the mouth of the Tugela. The loss of comparable habitat in KwaZulu-Natal is now nearly complete at least over this 225 km of coastline between the Mtamvuna and Tugela Rivers. A further decline of potential habitats is almost not possible as they are all already lost, making this species highly vulnerable to a catastrophic event, such as an attempt to develop the plot, which borders an important, interprovincial road and is close to the beach. The land on which the plants occur is currently privately owned and is unprotected, despite the fact that it contains 13 Pondoland endemics, six Near Threatened, five Vulnerable, one Endangered ( Eriosema umtamvunense C.H.Stirt.), and one Critically Endangered ( Hyobanche fulleri E.Phillips) species (http://redlist.sanbi.org). Furthermore, it has four species of Indigofera that have just been described ( Grieve et al. 2023), as well as an overlooked Exochaenium , which will be described in another paper. A potential long-term solution would be to extend the close-by Red Desert Nature Reserve, a conservation Stewardship Site managed by the Red Desert Conservation Trust, so that it incorporates the land on which the single subpopulation of E. edwardii occurs.

Additional material examined.

SOUTH AFRICA - KwaZulu-Natal • 3130AA; Port Edward, Rennies Beach; 10 m; 18 Feb. 2010; Abbott 9097; PCE [PCE0007850] photo, PRU, NU spirit • ibid.; 6 Feb. 2013; K.W. Grieve 726; NU spirit • ibid.; 17 Feb. 2014; Bytebier 3477; NU spirit • South of Port Edward ; 27 Feb. 2011; Church & Goodman s.n.; BR, NU .

Phylogenetic placement.

Martos et al. (2014) included this taxon (as E. ? Eulophia schnelliae ) in their phylogenetic sampling, where it was placed sister to E. ovalis , although only with weak support.

Taxonomic notes.

Apart from the diagnostic characters mentioned above, there are several, more subtle differences between E. edwardii and E. macowanii . The former has between 6 and 8 papery leaf sheaths, whereas the latter has seldom more than 5 leaf sheaths, which are of a firmer texture. The longest leaf sheath, found in the middle of the peduncle, is on average 80 mm in the former (and up to 115 mm), whereas in the latter it is seldom more than 60 mm. The lateral sepals are 7 mm wide or more in the former whereas they are seldom more than 6 mm in the latter. The width of the lip is usually more than 20 mm in the former and seldom more than 17 mm in the latter. Eulophia edwardii flowers in mid to late February, while most records for E. macowanii are from November and December. Eulophia macowanii is endemic to the Eastern Cape province, whereas E. edwardii occurs in KwaZulu-Natal (Fig. 3 ). Eulophia edwardii is also superficially similar to E. ovalis var. ovalis . Vegetatively they look very much alike, but the flowers are not comparable. The petals of E. edwardii are clearly spreading, whereas those of E. ovalis are bent forward over the lip. The side lobes of the lip are rounder and bigger in E. edwardii as compared to those of E. ovalis , and the papillae in E. edwardii end abruptly half way the lip, whereas those in E. ovalis extend further than half way. Eulophia ovalis has also not been recorded along the Pondoland Coast. The closest known population of E. ovalis occurs along the Mzimkhulu River about 70 km north-northeast of Port Edward.

Figures

Figure 1. Eulophia edwardii. A. Habit. B. Anther cap: side view and view from below. C. Pollinarium. D. Column: front and side view. E. Petal. F. Lip. G. Sepal. H. Pedicel, ovary, median sepal and part of lip showing spur. I. Apex of spur. J. Papillae on lip. K. Side view of flower. L. Front view of flower. M. Leaves. Figure drawn by Kate Grieve.

Figure 2. Eulophia edwardii. A. Inflorescence. B. Flower. C. Plant in habitat. Photographs A and B by Florent Martos; C by Graham Grieve.

Figure 3. Distribution map of E. macowanii (white circles and a yellow circle for the type specimen of E. schnelliae) and E. edwardii (red circle). Map produced with Google Earth Pro (data SIO, NOAA, U. S. Navy, NGA, GEBCO; image Landsat / Copernicus).