AFRICAN

ORCHIDS

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