The genus Eulophia in South Africa
The orchid genus Eulophia consists of about 200 species which are very widely distributed in Africa, and also occur in Central America, India and South-East Asia.
The earliest descriptions of members of this genus were based on plants from South Africa. They were published in the late 18th century by the younger Linnaeus and were placed in the genus Satyrium. The generic name was published by Robert Brown in 1821, and in the same article the generic name Eulophus was suggested for an allied series of species, without a description or any formal transfer of epithets. This name was validly published in the form Eulophia two years later by Lindley.
Preliminary studies in the genus Eulophia showed that while some groups could be distinguished from one another without difficulty, others showed complex intergrading series, with or without higher frequencies of one or more forms. Complex variation patterns of this sort have been recorded before in the genus Eulophia. chiefly among the tropical African team (e.g. de Wildeman 1919, Summerhayes 1933, 1958).
The present work was undertaken to provide a much-needed taxonomic revision of the South African members of the genus Eulophia R.Br. (Orchidaceae).
The genus is particularly well represented in South Africa where its distribution is centered in the Eastern Cape, KwaZulu-Natal, Mpumalanga and the Northern Province. While many Eulophias are endemic to this country, the distribution range of several species found here extends into Central and West Africa.
Key to the genus Eulophia in South Africa
1a | One or both petals, and sometimes the lip, fused to the gynostemium and variously distorted; spur elongate | Eulophia hians var. hians |
1b | Neither the petals nor the lip united with the gynostemium, or very rarely, if so, then the spur absent | 2 |
2a | Spur usually lacking, if present then less than 1.8 mm long; lip attached only to the apex of a prominent mentum; petals usually oblanceolate or broadly elliptic |
3 |
2b | Spur present; if obsolete, then either the lip attached to more than 1/3 the length of the mentum, or mentum absent; petals variously shaped |
7 |
3a | Lip crest a single ridge for most of its length, sometimes 3-lobed at its apex; median sepal 17-25 mm long | Eulophia tabularis |
3b | Lip crest of 2 ridges or lamellae, passing distally into several rows of lamellae; median sepal 5-18 mm long | 4 |
4a | Papillae wart-like and very sparse on the distal half of the lip midlobe; raceme generally dense and elongate | Eulophia foliosa |
4b | Papillae or lamellae elongate, usually numerous on the distal half of the lip midlobe; raceme both elongate and dense | 5 |
5a | Midlobe usually slightly more than half the length of the lip, with denticulate margins | Eulophia odontoglossa |
5b | Midlobe less than half total lip length, with smooth to finely undulate margins | 6 |
6a | Mentum passing into a distinct spur 1.2-1.8 mm long; raceme somewhat lax and elongate; sepals acute | Eulophia chlorantha |
6b | Spur absent; raceme dense and short; sepals subobtuse to subacute | Eulophia aculeata |
7a | Crests on the distal ⅔ of the lip composed of broad, smooth or verrucose ridges that gradually become lower to vestigial near the lip apex |
8 |
7b | Crests on the distal ⅔ of the lip composed of papillae or lamellae generally rather abruptly terminated, or the lip without crests in the distal ⅔ |
17 |
8a | Lip with a fringed lamella 2-4 mm high, set transversely near the base | Eulophia fridericii |
8b | Lip lacking a transverse lamella near the base | 9 |
9a | Petals and sepals reflexed, subequal; spur cylindrical, 4-5 mm long | Eulophia livingstoneana |
9b | Petals not reflexed, seldom subequal to the sepals; spur usually less than 4 mm long | 10 |
10a | Lip entire; pseudobulbs insignificant, aerial, flowering shoot arising laterally from an upper node; Swaziland | Eulophia callichroma |
10b | Lip 3-lobed | 11 |
11a | Distance from apex of lip side lobe to junction with midlobe 5-9 mm; leaves with a transverse line near the base marking an abscission layer |
Eulophia streptopetala |
11b | Distance from apex of lip side lobe to junction with midlobe 3 mm; leaves without a transverse line near the base | 12 |
12a | Gynostemium 2-4 mm long; margin of the lip midlobe undulate; median sepal 4-9 mm | Eulophia clilellifera |
12b | Gynostemium usually more than 5 mm long: rarely, if less, then margin of lip midlobe entire; median sepal 7-30 mm long | 13 |
13a | Lip margin rounded in a smooth curve at junction of lip side and midlobe; lateral sepals reflexed in the mature flower | 14 |
13b | Lip margin with an acute incision at junction of side and midlobe; lateral sepals not reflexed in the mature flower | 15 |
14a | Subcylindrical part of spur c. 3 mm long; lip midlobe incurved so that the central convexity lies close to the gynostemium |
Eulophia schweinfurthii |
14b | Subcylindrical part of spur less than 1 mm long; lip midlobe scarcely incurved, so that the central convexity lies distant from the gynostemium |
Eulophia speciosa |
15a | Petals often shortly clawed, obovate-elliptic; gynostemium 4-8 mm long; lip side lobes obliquely truncate | Eulophia parviflora |
15b | Petals never clawed, lanceolate-elliptic to ovate-oblong; gynostemium 7-9 mm long; side lobe apices rounded | 16 |
16a | Median sepal 12-15 mm long; lip midlobe irregularly denticulate; leaves 5 mm broad | Eulophia coddii |
16b | Median sepal 16-29 mm long; lip midlobe entire; leaves 7-16 mm broad | Eulophia cooperi |
17a | Sepals narrowly linear | 18 |
17b | Sepals oblong to lanceolate, ovate or obovate, not linear | 19 |
18a | Sepals 2x as long as the petals; lip midlobe broadly obovate | Eulophia longisepala |
18b | Sepals about as long as the petals; lip midlobe narrowly linear | Eulophia walleri |
19a | Lip crest composed of lamellae, either confined to the base or extending onto the midlobe; lamellae continuous or with a few incisions to the lip surface, smooth to crenulate |
20 |
19b | Lip crest composed of lamellae basally, passing into slender papillae in the distal parts of the lip; papillae -numerous and elongate, or rarely, few and short |
36 |
20a | Petals half the length of the median sepal, rotund-ovate | Eulophia meleagris |
20b | Petals more than ⅔ the length of the median sepal; if rotund-ovate then longer than median sepal | 21 |
21a | Lip crest of 2-3 tooth-like lamellae at the distal rim of a broad sac near the base of the lip | 22 |
21b | Lip crest usually extending along the greater length of the variously spurred lip; if the crests confined to the base, then the spur slender and cylindrical |
23 |
22a | Sepals acute | Eulophia cucullata |
22b | Sepals obtuse | Eulophia coeloglossa |
23a | Lip with a broadly rounded sac beneath the end of the gynostemium | Eulophia calanthoides |
23b | Lip without a broadly rounded sac beneath the end of the gynostemium | 24 |
24a | Flower scarcely resupinate at anthesis; crests confined to the basal 2/5 of the lip | Eulophia parvilabris |
24b | Flowers fully resupinate at anthesis; crests extending beyond the basal ½ of the lip | 25 |
25a | Mentum usually more than 4 mm long; if less (2 mm long), then either the petals 19-30 mm long or the spur vestigial | 26 |
25b | Mentum usually absent; rarely, if up to 2 mm long, then the petals 8-15 mm long; spur always elongate, 2-9 mm long | 33 |
26a | Crests of low crenulate ridges less than 0.5 mm high | Eulophia coddii |
26b | Crests of stout lamellae standing 1.3-5 mm high | 27 |
27a | Spur lacking, or present as a small boss on the mentum; median sepal less than 9 mm long | Eulophia tuberculata |
27b | Spur present, usually cylindrical to conical, if shortly conical then the median sepal more than 12 mm long | 28 |
28a | Margins near base of lip midlobe crispate-undulate; operculum bilobed | 29 |
28b | Margins near base of lip midlobe nearly smooth; operculum not bilobed | 32 |
29a | Leaves with serrulate margins; petals acuminate, narrowly oblong, apices often circinnate | Eulophia petersii |
29b | Leaves with entire margins; petals obtuse, or if subacuminate then rotund to elliptic-oblong, apices never circinnate | 30 |
30a | Sepals obtuse, slightly longer than the suboblong petals | Eulophia angolensis |
30b | Sepals acute to apiculate, slightly shorter than the subrotund petals | 31 |
31a | Midlobe of lip acute to shortly rounded, oblong to sub-ovate, junction with side lobes abrupt | Eulophia horsfallii |
31b | Midlobe of lip truncate, transversely oblong, merging smoothly with side lobes | Eulophia latilabris |
32a | Lip midlobe subdeltoid; crest lamellae present on main side lobe veins | Eulophia hereroensis |
32b | Lip midlobe broadly obovate; crests absent on side lobes | Eulophia platypetala |
33a | Median sepal 5-10 mm long; crests of low, stout lamellae; spur 2-3 mm long | 34 |
33b | Median sepal usually more than 12 mm long; when less (8.5 mm long) then the crests of tall, thin lamellae; spur 3-9 mm long |
35 |
34a | Lip side lobes subelliptic, not overlapping midlobe margins, widely divergent from the median axis of lip | Eulophia zeyheriana |
34b | Lip side lobes subrhomboid, overlapping part of the base of the midlobe, with only the apex slightly divergent | Eulophia tenella |
35a | Spur conical from the base to near the apex | Eulophia platypetala |
35b | Spur cylindrical and slender for most of its length | Eulophia hians var. hians |
36a | Petals 1.2-2.6 times as broad as the lateral sepals, and usually ovate to oblong; if suboblanceolate, then clearly much wider |
37 |
36b | Petals nearly always a little narrower than the lateral sepals and oblanceolate to narrowly oblong; if slightly wider, then clearly oblanceolate |
42 |
37a | Rostellum with a fine papilla 1.2 mm long on either side; leaf-bases with a transverse line marking an abscission layer |
Eulophia leachii |
37b | Papillae lacking on either side of the rostellum; leaf-bases lacking the transverse line of an abscission layer | 38 |
38a | Flowers not or very slightly resupinate at anthesis; spurs 5-8 mm long | Eulophia macowanii |
38b | Flowers either resupinate at anthesis, or if not, then spurs less than 3 mm long | 39 |
39a | Lip longer than the sepals, midlobe basally dentate; petals slightly wider than the lateral sepals | Eulophia holubii |
39b | Lip usually shorter than the sepals, midlobe entire; petals mostly much wider than the lateral sepals | 40 |
40a | Leaves less than half the length of the scape at anthesis; spur 1.2-2.2 mm long; crest papillae few, confined to the basal ⅓ of the lip midlobe |
Eulophia. cooperi |
40b | Leaves usually more than ⅔ the length of the scape at anthesis; if less then the spur more than 3 mm long and crest papillae numerous over most of the lip |
41 |
41a | Petals ovate, tapering to a subacute apex | Eulophia ovalis |
41b | Petals oblong to elliptic-oblong or slightly obovate-oblong, acute or obtuse; if slightly ovate-oblong, then very obtuse | Eulophia hians var. hians |
42a | Median sepal 3-8 mm long; raceme elongate; mentum absent; spur apex nearly always lying against the ovary | Eulophia milnei |
42b | Median sepal 7-46 mm long; when 7-10 mm long either raceme a globose head, or mentum present and spur apex lying away from the ovary |
43 |
43a | Gynostemium 10-13 mm long; lip side lobes with acute apices; midlobe with stout erect papillae | Eulophia litoralis |
43b | Gynostemium usually 3-8 mm long; if 9-12 mm long, then lip side lobes with broadly rounded apices; midlobe with slender flexuose papillae |
44 |
44a | Cylindrical portion of the spur shorter than the mentum; gynostemium 9-12 mm long | Eulophia adenoglossa |
44b | Cylindrical portion of the spur usually much longer than the mentum; if nearly as long then gynostemium 3-4 mm long | 45 |
45a | Crest papillae very few on the distal half of the lip midlobe; midlobe 9-20 mm long | Eulophia welwitschii |
45b | Crest papillae usually numerous on the distal half of the lip midlobe; if few, then midlobe 2-4 mm long | 46 |
46a | Crest papillae few, c. 5-15; raceme rather lax; gynostemium 3-4 mm long | Eulophia chlorantha |
46b | Crest papillae numerous, 40-80 or more; raceme dense; gynostemium 4-8 mm long | 47 |
47a | Midlobe ⅓ the length of the lip, excluding spur; apices of the lip side lobes acute; scape c. 60-300 mm tall | Eulophia leontoglossa |
47b | Midlobe half the length of the lip, excluding spur; apices of the lip side lobes obtuse; scape c. 300-1000 mm tall | Eulophia ensata |
References:
Duncan, G.D. 1989. Eulophia. In: Du Plessis, N.M. and G.D. Duncan, Bulbous plants of southern Africa: 172-174. Tafelberg, Cape Town.
Hall, A.V. 1965. Studies of the South African species of Eulophia. Journal of South African Botany, supplementary vol. 5: 153-157. National Botanic Gardens of South Africa, Cape Town.
Linder, H.P. and H. Kurzweil, 1999. Orchids of Southern Africa. Balkema, Rotterdam.
Pooley, E., 1998. A field guide to wildflowers KwaZulu-Natal and the Eastern Region: 372-373. Natal Flora Publications Trust, Durban.
World Checklist of Monocotyledons. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/monocots/ accessed 25/08/2019