Epipactis atrorubens Besser 1809
Creators: name: Brullo, Salvatore
name: Brullo, Cristian
name: Cambria, Salvatore
name: Tavilla, Gianmarco
name: Pasta, Salvatore
name: Scuderi, Leonardo
name: Zimmitti, Angelo
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Asparagales
Orchidaceae
Epipactis
Epipactis atrorubens

description: Key to the species of the Epipactis atrorubens group   
1. Stem densely pubescent, cauline leaves 3–5 (rarely more)................................................................................................................2  
- Stem glabrous basally and pubescent higher up, cauline leaves (4)5–11...........................................................................................4  
 2. Leaf longer than internode, back of sepals and petals whitish green, hypochile 4.0– 5.5 mm wide, epichile scalloped marginally, viscidium absent, ovary not pyriform........................................................................................................................ E. krymmontana   
- Leaf shorter than internode, back of sepals and petals green tinged with red or purple, hypochile 3.0–4.0 mm wide, epichile crenulated marginally, viscidium present, ovary pyriform.................................................................................................................3  
 3. Cauline leaves 1.5–2.2 mm wide, leaf margin with 14–15 teeth per mm, back of sepals and petals glabrous or sparsely pubescent, dorsal sepal with 2 nerves, epichile 5–6 mm wide, ovary 9–12 mm long..................................... E. microphylla subsp. cossyrensis   
 - Cauline leaves 0.5–1.5(2.0) mm wide, leaf margin with 10–12 teeth per mm, back of sepals and petals pubescent, dorsal sepal with 1 nerve, epichile 3–4 mm wide, ovary 6–9 mm long.................................................................... E. microphylla subsp. microphylla   
 4. Sepals with 4–5 nerves, lateral sepals 5–7 mm wide, petals 9.0–10.0 × 5.0–6.0 mm, anther brown........................... E. condensata   
- Sepals with 1–3 nerves, lateral sepals 2–5 mm wide, petals 3.5–9.0 × 2.0– 4.5 mm, anther yellow to greenish yellow...................5  
 5. Back of sepals subglabrous, front of petals glabrous, epichile yellow to pink, 5.0–6.0 mm wide, margin scalloped.. E. spiridinovii   
- Back of sepals pubescent, front of petals pubescent to subglabrous, epichile dark purple to violet, 3.0– 4.5 mm wide, margin denticulate to crenulate.......................................................................................................................................................................6  
 6. Hypochile 2.0–3.0 mm wide................................................................................................................................................ E. kleinii   
- Hypochile 3.8–4.5 mm wide..............................................................................................................................................................7  
 7. Sepals 5–6 mm long, dorsal sepal 2.5–3.0 mm wide, lateral sepals with 3 nerves, petals 4.0–5.0 mm long................. E. subclausa   
- Sepal 6–10 mm long, dorsal sepal 3.5–5.0 mm wide, lateral sepals with 2 nerves, petals 5.5–9.0 mm long....................................8  
 8. Basal bracts 10–30 mm long, flowers usually dark red to purple, lateral sepals 2.5–4.0 mm wide, petals 2.5–3.5 mm wide, back pubescent, laterally 2 nerved, ovary 4–6 mm long......................................................................................................... E. atrorubens   
 - Basal bracts 30–60 mm long, flowers usually greenish yellow, lateral sepals 4.5–5.0 mm wide, petals 4.0– 4.5 mm wide, back subglabrous, laterally 3 nerved, ovary 6–8 mm long.......................................................................................................... E. cardina
description: Published as part of Brullo, Salvatore, Brullo, Cristian, Cambria, Salvatore, Tavilla, Gianmarco, Pasta, Salvatore, Scuderi, Leonardo & Zimmitti, Angelo, 2021, A new subspecies of Epipactis microphylla (Orchidaceae; Epidendroideae) from Pantelleria Island (Sicily), pp. 83-96 in Phytotaxa 512 (2) on page 92, DOI: 10.11646/phytotaxa.512.2.1, http://zenodo.org/record/5304949