Epidendrum, Linnaeus (1763:, 1347

Quispe-Melgar, Harold Rusbelth, Llacua-Tineo, Elizabeth Santiago Ayala Yashira Stefani & Hágsater, Eric, 2023, Synopsis of the Peruvian species of Epidendrum (Orchidaceae: Laeliinae) belonging to the Scabrum group, subgroup Soratae: diversity and description of a new species, Phytotaxa 603 (1), pp. 1-26 : 6-7

Key to Peruvian species of Epidendrum belonging to the Scabrum group, Soratae subgroup .

1. Lip clearly 3-lobed .............................................................................................................................................................................2

- Lip entire to slightly 3-lobed, if 3-lobed the mid-lobe short and incipient ........................................................................................6

2. Leaves unequal in size, those of primary stem larger than those of branches....................................................................................3

- Leaves similar in size, those of primary stem equal to those of branches..........................................................................................4

3. Sepals with acuminate apex; lip 7–8.4 × 8–10 mm, mid-lobe flabelliform, “T” shaped, with margin entire and prominently apiculate............................................................................................................................................................... E. chrysomyristicum

- Sepals with acute apex; lip 4.6–6 × 6.5–8 mm, the mid-lobe rectangular with apex slightly widened and rounded, margin crenate, no apiculate....................................................................................................................................................................... E. fruticulus

4. Plants 12–20 cm tall, much branched; petals 0.3–0.4 mm wide, linear-filiform.............................................................. E. physopus

- Plants 60–185 cm tall, scarcely branching; petals 1.6–1.8 mm wide, linear-oblanceolate ................................................................5

5. Column 7–8 mm long; flowers red-purple with the column and lip yellow dotted with red; mid-lobe of lip rectangular.................. ................................................................................................................................................................................... E. stictoglossum

- Column 5 mm long; flowers yellow tinged brown, immaculate; mid-lobe of lip subtriangular......................................... E. ypsilum

6. Lateral sepals strongly reflexed.................................................................................................................................. E. retrosepalum

- Lateral sepals spreading or partly spreading ......................................................................................................................................7

7. Flowers red, yellow to ochre yellow ..................................................................................................................................................8

- Flowers creamy white, green-yellow or pale green..........................................................................................................................13

8. Lip cordiform; leaves nearly parallel to stem............................................................................................................... E. scopulorum

- Lip transversely orbicular-reniform, ovate to elliptic; leaves spreading to sub-spreading to stem................................................... 9

9. Lip with margin spreading................................................................................................................................................................12

- Lip strongly revolute (mainly the apex) ...........................................................................................................................................10

10. Flowers carmine-red with yellow disc; petals 8 × 1.5 mm, linear-oblanceolate; calli very small and globose......... E. jose-alvarezii

- Flowers ochre-red to green-brown, lip yellow, concolor or spotted red; petals 8–20 mm long, filiform to obtrulliform, calli prominent, laminar or laterally compressed .....................................................................................................................................11

11. Petals 8 × 0.3 mm, filiform; calli prominent, laminar .................................................................................................. E. labrychilum

- Petals 20 × 4.8–5.3 mm; trullate, base long attenuate; lip 17.5 × 14 mm, entire, narrowly ovate, apex acute............ E. unchogense

12. Petals 0.3–0.8 mm wide, filiform to linear; lip 3.2–10.2 × 4.5–9 mm, orbicular, orbicular-reniform, narrowly elliptic or transversely elliptic; flowers yellow to ochre, tinged red.....................................................................................................................................24

- Petals 1 mm wide, linear; lip 4–7 × 6–10.2 mm, reniform; flower carmine red or orange, concolor.................................. E. ardens

13. Lateral sepals 18 mm long, apex strongly concave; ovary strongly arched with a very prominent vesicle along apical half............. ................................................................................................................................................................................................... E. sp.1

- Lateral sepals 3.7–16 mm long, concave to convex; ovary not arched, with short or elongate vesicle...........................................14

14. Lip entire, sub-orbicular; petals 15 × 4 mm; flowers doted purple black at apex of column and disc of the lip .... E. yanachagaënse

- Lip bilobed, to slightly 3-lobed or sub-entire; petals 4–12 × 0.5–1.5 mm; flowers immaculate .....................................................15

15. Sepals 12–15 mm long .....................................................................................................................................................................16

- Sepals 3.7–8.7 mm long ...................................................................................................................................................................17

16. Flowers emerald green; lip bilobed (hexagonal in general shape), widely mucronate; calli laminar, strongly divaricate .................. ........................................................................................................................................................................................ E. cardenasii

- Flowers green-yellow; lip slightly 3-lobed (reniform in general outline), mid-lobe shorter than lateral lobes, apex truncate; calli fleshy, somewhat laterally compressed ................................................................................................................................ E. llatasii

17. Lip sub-triangular, base cuneate; callus very prominent.......................................................................................................... E. sp. 2

- Lip reniform, base cordate; calli small .............................................................................................................................................18

18. Flowers white or creamy yellow ......................................................................................................................................................19

- Flowers pale green or green brown ..................................................................................................................................................21

19. Sepals 7.8–8.0 mm long; lip slightly 3-lobed widely apiculate at apex ..................................................................... E. monteagudoi

- Sepals 3.7–5.0 mm long; lip entire, reniform, without any triangular apiculus at apex...................................................................20

20. Flowers creamy-yellow; lip with base clearly and deeply cordate at base; leaves 0.7–2.5 cm long, the apex rounded and bilobed .. ...................................................................................................................................................................................... E. carpishense

- Flowers white; lip with base slightly cordate; leaves 0.3–1.7 cm long, apex obtuse, not bilobed ................................... E. moscozoi

21. Leaves up to 1.7 cm long, linear-lanceolate with apex truncate; inflorescence two-flowered; lip with margin erose ........................ ........................................................................................................................................................................................... E. leonorae

- Leaves up to 4.7 cm long, lanceolate, apex obtuse to sub-acute; inflorescence with 8–12 flowers; lip with margin entire to undulate ............................................................................................................................................................................................22

22. Lip with apex clearly emarginate; leaves 3.6–4.7 × 0.4–0.8 cm; lip 4.6–6.5 × 8.0– 8.2 mm ...........................................................23

- Lip with apex slightly emarginate; leaves 2.0–2.5 × 1.0– 1.5 cm; lip 4 × 6 mm ........................................................... E. centralense

23. Sepals 6.8–7.0 mm long, obovate-elliptic; apex of lip bidentate; ovary with a prominently inflated vesicle from the middle of column to apex of ovary...................................................................................................................................................... E. soratae

- Sepals 8.0– 8.5 mm long, obovate, oblanceolate; apex of lip slightly bilobed; ovary with a small, incipient vesicle behind lateral sepals ................................................................................................................................................................................ E. obliquum

24. Column abruptly constricted near base or thin at base and widened at apex; margin of sepals spreading ......................................25

- Column constricted near apex; margin of sepals revolute........................................................................................... E. vesicolumna

25. Lateral sepals 12.0– 12.5 mm long, strongly falcate, lip 10.2 × 6.3 mm, narrowly elliptic, base truncate................... E. ovatilabium

- Lateral sepals 5.5–8 mm long, occasionally oblique but not falcate; labellum 3.2–8 × 4.5–6 mm, orbicular to orbicular-reniform with base cordate ..............................................................................................................................................................................26

26. Flowers yellow; column thin at base, gradually wider towards apex, apex arching downwards............................... E. yasgolgaënse

- Flowers ochraceous, somewhat tinged red; column strongly constricted at base, apex arched upwards .............. E. constricolumna