Key to the genus Eulophia in Flora tropical east Africa

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