AFRICAN

ORCHIDS

The genus Eulophia in Flora tropical east Africa (Uganda, Kenya, and Tanzania.)
I have followed here Summerhayes (1968) in F.W.T.A. Orchidaceae, Hall (1965) in the Journal of South African Botany Suppl. 5 and other recent authors in including Lissochilus in Eulophia. However, in the absence of an explanatory argument I have not followed Geerinck (1987) who, in his Flore du Rwanda orchid account, has included the genera Oeceoclades and Pteroglossaspis in Eulophia.
Despite its morphological diversity, no satisfactory infrageneric treatment of Eulophia in Africa exists. In this treatment I have attempted to place closely related species together. However, an infrageneric treatment needs to take into account species from outside the present study area and this work is as yet incomplete.
I have adopted a broad species concept for this treatment, in accordance with that adopted by Summerhayes (1968) and Hall (1965). Many of the species in Eulophia are widespread in Africa and there are few narrow endemics. Variations in plant stature, leaf size and flower size are found in several species, e.g. E. speciosa, E. cucullata and E. streptopetala. Some of this variation may be due to polyploidy which has been reported in several African species (Hall (1965) Poggio et al. in K.B. 41: 45-49 (1986)).
Key to the genus Eulophia in Flora tropical east Africa

1 Plants saprophytic, lacking leaves entirely but with pale buff stems and bracts  2
1a Plants autotrophic or only partly saprophytic, usually with green, greenish or purplish stems, leaves and bracts  3
2 Sepals and petals 15-25 mm. long; lip papillate all over, with a maroon mark at the base; bracts 28-50 mm. long  Eulophia galeoloides
2a Sepals and petals 4.5-6 mm. long; lip with a 4-ridged basal callus but otherwide glabrous; bracts 3-4 mm. long  Eulophia epiphanoides
3 Inflorescence paniculate, with several spreading branches  4
3a Inflorescence racemose, rarely with a single branch  5
4 Leaves coriaceous, thick, with serrated margins; sepals and petals 16-23 mm. long, recurved at the apex; lip 3-lobed  Eulophia petersii
4a Leaves thin-textured, lacking serrated margins; sepals and petals 6-9 mm. long, not recurved at the apex; lip entire, spathulate  Eulophia callichroma
5 Leaves fleshy-coriaceous, with serrated margins  6
5a Leaves thin-textured to somewhat fleshy, without serrated margins  7
6 Sepals and petals 19-25 mm. long; lip 18-20 mm. long; leaves 8 or more  Eulophia taitensis
6a Sepals and petals 10 mm. or less long; lip 9 mm. or less long; leaves ±4  Eulophia stricta
7 Spur 15-25 mm. long, straight and parallel to the ovary, conical at the base, tapering to the apex; lip obscurely
3-lobed, with auriculate side lobes and a large purple or pink, flat, ecallose mid-lobe, 20-26 mm. long, 17-32 mm. wide
Eulophia guineensis
7a Spur and lip not as above  8
8 Pseudobulbs 16-25 cm. long, 1-1.5 cm. in diameter, narrowly cylindrical; flowers green with a white lip marked with
a transverse pink or purple band across the base of the mid-lobe; spur straight, clavate
Eulophia euglossa
8a Pseudobulbs, if present, not as above  9
9 Sepals spathulate, rounded and somewhat concave at the apex, usually ± erect  10
9a Sepals and petals not like that  13
10 Lip ± ecallose, pale lilac or white with the 5 central veins only slightly thickened; sepals white with a greenish apex; petals white  Eulophia malangana
10a Lip with a 2-5-ridged callus, yellow, purple or rarely white; sepals yellow, brown or purple; petals yellow or rose-pink 11
11 Petals and lip yellow; petals yellow or brown; callus of 3 crenulate ridges raised in basal half and tapering to the apex Eulophia angolensis
11a Petals and lip pink or rarely white; callus not as above 12
12 Lip 12-15 mm. long; callus of 2 subquadrate ridges in the basal half of the lip Eulophia coeloglossa
12a Lip 18-21 mm. long; callus of 3 verrucose ridges at the base of the lip with 5 cristate ridges in front Eulophia caricifolia
13 Callus with 2 prominent subquadrate raised flaps in basal part or middle of the lip 14
13a Callus lacking such flaps 15
14 Sepals, petals and lip pink to rose-purple; lip 18-34 mm. long, 20-40 mm. wide when flattened, lacking papillae on the veins
in the apical half
Eulophia cucullata
14a Sepals and petals olive-green or green; lip purple or rarely white, 14-19 mm. long, 8-12 mm. wide, papillate on veins in apical half Eulophia alta
15 Petals circular, broadly elliptic or obovate, as broad as long or almost so  16
15a Petals linear, lanceolate, oblong or narrowly elliptic, much longer than broad 29
16 Lip more than 20 mm. long, adorned with 3-7 lamellate ridges; petals usually more than 20 mm. wide, pink to rose-purple  17
16a Lip less than 16 mm. long, adorned with 1-7 low, rounded, rugulose ridges; petals less than 19 mm. wide, yellow to
brown or rarely lilac, often veined with red 
18
17 Lip much longer than broad when flattened, distinctly 3-lobed; callus of 3 ridges; petals 15-24 mm. wide, with slightly
reflexed margins 
Eulophia horsfallii
17a Lip as broad as long when flattened, obscurely 3-lobed; petals 25 mm. or more wide, concave Eulophia latilabris
18 Flowers with a thin transverse lacerate-margined lamella near the base of the lip; lip lacking a spur at the base  19
18a Flowers lacking such a transverse lamella at the base of the lip; spur usually present  20
19 Petals and lip yellowish; petals 5-6.5 mm. long  Eulophia fridericii
19a Petals and lip lilac or pinkish; petals 9-11 mm. long  Eulophia gonychila
20 Plants with prominent ovoid pseudobulbs above the ground; leaves plicate, usually more than 1 cm. wide  Eulophia streptopetala
20a Plants with underground tubers or rhizomes; leaves fleshy or plicate, usually less than 1 cm. wide  21
21 Flowers large; petals more than 11 mm. long; lip more than 12 mm. long  22
21a Flowers small; petals 10 mm. or less long; lip 9 mm. or less long  24
22 Flowers bright yellow with a little red venation on the lip; base of lip obscurely conical, obtusely angled  Eulophia speciosa
22a Flowers not so coloured; petals reddish, brown or yellow veined with red; lip spurred at the base;
spur 8-16 mm. long measured from the base of the ovary 
23
23 Spur ± straight or decurved at the apex, cylindrical from a conical mouth, 13-16 mm. long from the base of the ovary  Eulophia orthoplectra
23a Spur upcurved at the apex, the ovary  Eulophia schweinfurthii
24 Spur very short or obscure, 1-2.5 mm. long  25
24a Spur more than 3 mm. long  27
25 Lip obtuse at the base but lacking a true spur; lip mid-lobe reduplicate; petals and lip yellow  Eulophia tuberculata
25a Lip spurred at the base; lip mid-lobe flat or concave; petals and lip greenish or yellow, heavily marked with brown  26
26 Spur 1 mm. long or less; petals 5-5.5 mm. long  Eulophia parvula
26a Spur 1.5-2.5 mm. long; petals 6-8 mm. long  Eulophia pyrophila
27 Callus on the lip 9-ridged; lip 10.5-11.5 mm. long  Eulophia stenoplectra
27a Callus on the lip 3-5-ridged; lip less than 10.5 mm. long  28
28 Lip 6-10.5 mm. long; spur 3-5 mm. long; inflorescence produced before the leaves appear Eulophia clitellifera
28a Lip 4.5-5.5 mm. long; spur 5-6 mm. long; inflorescence produced with the young leaves  Eulophia leonensis
29 Sepals strongly reflexed; petals elliptic, appressed to the column Eulophia calanthe
29a Sepals and petals not as above 30
30 Side lobes of the lip spreading widely; sepals spreading widely; lip mid-lobe deflexed, broadly spreading 31
30a Side lobes and mid-lobe of the lip and the sepals not as above  33
31 Sepals lanceolate, greenish; lip and petals pale yellow; lip alia 23-29 mm. long; callus obscure; petals appressed to the column Eulophia flavopurpurea
31a Sepals oblanceolate, lilac; petals spreading, lilac; lip 12-22 mm. long, deep purple; callus of 5-9 ridges  32
32 Lip with 5-9 crenulate or papillate ridges on the mid-lobe  Eulophia cristata
32a Lip with 5-9 smooth ridges on the midlobe  Eulophia livingstoneana
33 Sepals, petals and lip with a similar base-colour: white, pink, purple, yellow, orange or green; sepals and petals similar in shape  34
33a Sepals and petals dissimilar in colour and often also in shape; lip of a different colour  48
34 Flowers bright orange  35
34a Flowers not orange-coloured  36
35 Sepals 4 mm. or more wide; lip broadly 3-lobed, 10 mm. or more wide; spur 1-2 mm. long  Eulophia aurantiaca
35a Sepals linear, 3 mm. or less wide; lip narrowly 3-lobed, less than 9 mm. wide; spur absent Eulophia walleri
36 Flowers yellow or greenish, sometimes with markings of a different colour on the lip  37
36a Flowers white, pink, purple or brown, sometimes with markings of a different colour on the lip 43
37 Lip narrowly 3-lobed, with the side lobes almost as long as the narrow mid-lobe; lip with an orange mark on the lip  Eulophia nuttii
37a Lip broadly 3-lobed, with the side lobes much shorter than the midlobe 38
38 Flowers green or yellowish green with brownish purple veining on the side lobes of the lip;
spur strongly incurved-conical, up to 5 mm. long 
Eulophia adenoglossa
38a Flowers predominantly yellow or pale yellow; spur cylindrical  39
39 Sepals 14 mm. or less long; lip 11.5 mm. or less long; peduncle covered or almost covered by papery sheathing bracts  40
39a Sepals 17 mm.or more long; lip 12 mm.or more long-,peduncle not entirely covered by sheathing bracts 41
40 Lip 8-11.5 mm. long, with orange or red papillae on the mid-lobe; sepals 9-14 mm. long; pedicel and ovary 12-21 mm. long  Eulophia odontoglossa
40a Lip 6-7 mm. long, with yellow papillae on the mid-lobe; sepals 5-9.5 mm. long; pedicel and ovary 5-8 mm. long  Eulophia milnei
41 Lip 12—14 mm. long; inflorescence secund; flowers pale yellow with a greenish mark on the lip, sometimes with ,a purplish border  Eulophia carsonii
41a Lip more than 15.5 mm. long; inflorescence a dense head; flowers yellow or yellow with a purple or dark yellow mark on the lip 42
42 Flowers pale yellow to yellow, lacking a differently coloured mark on the lip; petals 15-26 mm. long; lip 15-24 mm. long  Eulophia subulata
42a Flowers yellow with a maroon or orange mark on the lip; petals 28-32 mm. long; lip 23-26 mm. long Eulophia mechowii
43 Flowers white or pink with a dark maroon or purple spot on the lip  44
43a Flowers white, pink, purple or brown, but without a distinct darker spot on the lip 45
44 Flowers pure white with a dark maroon spot on the midlobe of the lip in front of 7 lines of yellow papillae  Eulophia thomsonii
44a Flowers pale to darker pink with a purple spot on the lip; callus of 2 papillate ridges at the base and long papillae in front Eulophia euantha
45 Flowers dull purple or brown  46
45a Flowers not so coloured 47
46 Peduncle covered by papery sheathing bracts; petals 8-12 mm. long; lip 8-11.5 mm. long  Eulophia odontoglossa
46a Peduncle not completely covered by sheathing bracts; petals 12-15 mm. long; lip 12 mm. or more long Eulophia rara
47 Inflorescence markedly secund; sepals and petals slender, 3-3.5 mm. wide; lip mid-lobe obovate, truncate Eulophia trilamellata
47a Inflorescence not secund; sepals and petals 6-10 mm.wide; lip midlobe subquadrate  Eulophia montis-elgonis
48 Leaves 18-85 mm. wide, obviously plicate  49
48a Leaves grass-like, less than 10 mm. wide 50
49 Callus on the lip comprising 3 basal ridges with 5 rows of short papillae in front on the mid-lobe  Eulophia stachyodes
49a Callus on the lip comprising 2 basal ridges and a dense mass of long papillae in front on the midlobe Eulophia elegans
50 Plants with proximate cylindrical-conical pseudobulbs, usually partly or wholly above ground  51
50a Plants with underground, irregularly shaped tubers or fleshy rhizomes 60
51 Fruits erect  52
51a Fruits pendent 53
52 Spur straight, 8-10 mm. long; sepals 16-18 mm. long; lip 7-9 mm. wide; callus 3-ridged at base with papillae in front  Eulophia. katangensis 
52a Spur incurved, 3-5 mm. long; sepals 11-14 mm. long; lip 9-12 mm. wide; callus of 3 basal ridges with 5-7 verrucose ridges in front  Eulophia rhodesiaca
53 Lip purple or with a purple or lilac margin; spur deflexed, ± as long as the deflexed midlobe
of the lip; leaves lanceolate, usually 5 mm. or more wide 
54
53a Lip not as above; leaves 1-4 mm. wide  55
54 Petals 9-12 mm. long, 2-3 mm. wide; Up mid-lobe purple; spur 4-5 mm. long, somewhat sigmoid-decurved Eulophia sabulosa
54a Petals 8-8.5 mm. long, 1.5-2 mm. wide; lip green with a yellow centre and lilac margin to the
midlobe; spur 3-4 mm. long, incurved 
Eulophia seleensis
55 Lip mid-lobe circular, about a third to half the length of the lip; spur straight, distinctly clavate Eulophia penduliflora
55a Lip mid-lobe ovate to oblong, about half the length of the lip; spur usually incurved and cylindrical, rarely clavate  56
56 Lip bright yellow  Eulophia mumbwaensis
56a Lip white, green or pinkish  57
57 Lip 15-17 mm. long, 13 mm. wide when flattened; mid-lobe oblong-obovate, with an undulate margin; sepals
green, ± shaded with pale brown; leaves 3-4
Eulophia tanganyikensis
57a Lip less than 10 mm. long; mid-lobe ovate to lanceolate; sepals brown or maroon, 1-2 mm. wide; leaves 5-8  58
58 Sepals recurved; callus with short papillae on the three middle veins of the  Eulophia venulosa
58a Sepals erect; callus with short papillae or crenulate ridges on the midlobe  59
59 Spur clavate, 3-4 mm. long; petals chocolate-brown; midlobe of the lip with 3-5 rows of crenulate ridges  Eulophia massokoensis
59a Spur incurved, cylindrical, 4-5 mm. long; petals white midlobe of the lip with 3 rows of papillae Eulophia monotropis
60 Fruits erect; flowers ± erect 61
60a Fruits pendent; flowers spreading to nutant 63
61 Flowers opening widely; sepals erect, 15-32 mm. long usually about twice as long as the petals; spur 2 mm long Eulophia longisepala
61a Flowers not opening widely; sepals not erect, 12-19 mm long, only slightly longer than the petals; spur 2-6 mm long  62
62 Sepals and petals greenish, flecked with red-brown; spur decurved, 5-6 mm. long; lip white with
red veins on the side lobes, 9-9.5 mm. long; midlobe of the lip unspotted, with an undulate margin 
Eulophia nyasae
62a Sepals and petals deep purple or brown; spur ± straight, 4-5.5 mm. long; lip white with yellow side lobes, veined
with purple, and a purple-spotted midlobe
Eulophia subsaprophytica
63 Petals yellow, 20-24 mm. long, 8-9 mm. wide; lip yellow with red-veined side lobes, 15-21 mm. long, 10-15 mm. wide  Eulophia ovalis
63a Petals white, green or yellowish green, less than 12 mm. long; lip white, green, yellow or
yellowish green, less than 15 mm. long, 10 mm. wide
64
64 Spur markedly dilated at the apex  65
64a Spur cylindrical, ± incurved  66
65 Spur tightly incurved, 3-4 mm. long; lip yellow, 4-6 mm. long, 1.5-2 mm. wide Eulophia monile
65a Spur slighdy incurved, 2-3 mm. long; lip white with a pale green callus, 6-8.5 mm. long, 2.5-4 mm. wide Eulophia monile Syn E. norlindhii 
66 Sepals erect, 9-17 mm. long; lip 9-15 mm. long, green with a white or yellow mid-lobe; callus of 3 fleshy ridges
at base of lip and papillae in front on the midlobe 
Eulophia kyimbilae
66a Sepals not erect, 10-12 mm. long; flower not opening widely; lip white flushed with dull purple, 7-10 mm. long;
callus of 2 basal ridges with papillae on the midlobe 
Eulophia hians var. hians

References:
Flora Tropical east Africa Orchidaceae (Part 3)
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 21/08/2019