Centaurea (sect. Acrocentron) Candolle 1838
Creators: name: Negaresh, Kazem
name: Yousefi, Zohreh
name: Kaya, Yusuf
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Asterales
Asteraceae
Centaurea

description: Key to species of Centaurea sect. Acrocentron in Iran
1. Flowers yellow or whitish ..................................................................................................................................................................2
- Flowers purple or dark purple ............................................................................................................................................................3
2. Stems branched from lower to upper parts, with several capitula; involucres subglobose, 20–30 mm wide; appendages straw-coloured, 5–7 mm wide at base (cilia excluded); terminal spine 20–35 mm long; flowers yellow............................... C. sosnovskyi
- Stems simple, monocephalous; involucres cupuliform, 35–40 mm wide; appendages brown, 3–5 mm wide at base (cilia excluded); terminal spine 4–13 mm long; flowers whitish ............................................................................................................ C. zangulensis
3. Flowers dark purple................................................................................................................................................. C. kandavanensis
- Flowers purple ....................................................................................................................................................................................4
4. Plant entirely glabrous; appendages without spine .................................................................................................. C. sanandajensis
- Plant hairy; appendages with distinct spine........................................................................................................................................5
5. Involucres 12–18(–20) mm wide; appendages concealing minor part of phyllaries..........................................................................6
- Involucres (20–) 25–35 mm wide; appendages concealing totally or major part of phyllaries ..........................................................9
6. Plants dwarf, up to 5 cm height; basal and lower cauline leaves lyrate; spine <12 mm long...........................................................7
- Plants tall, (20–) 30–60 cm height; basal and lower cauline leaves pinnatisect or pinnatipartite; spine> 12 mm long.....................8
7. Stems densely floccose-tomentose; leaves above loosely floccose-tomentose, below sparsely pilose-articulate; involucres 12–13 mm wide; phyllaries glabrous; appendages brown, 1–2.5 mm wide at base (cilia excluded); achenes 3.8–4 mm long; pappus 6–6.2 mm long...................................................................................................................................................................... C. bojnordensis
- Stems densely arachnoid; leaves loosely arachnoid; involucres (12–) 15–20 mm wide; phyllaries loosely arachnoid; appendages straw-coloured or light brown, 2–4 mm wide at base (cilia excluded); achenes 4.2–4.8 mm long; pappus 8–9 mm long ................. ........................................................................................................................................................................................ C. serowensis
8. Plants perennial, many-stemmed; stems branched from basal to upper parts; involucres 15–18 mm wide; appendages 3–5 mm wide at base (cilia excluded); pappus (8–) 10–11 mm long.......................................................................................................... C. irritans
- Plants biennial, few-stemmed; stems branched only in upper part; involucres 18–22 mm wide; appendages 1–3 mm wide at base (cilia excluded); pappus 5–6 mm long ................................................................................................ C. carduiformis subsp. iranica
9. Stems floccose-tomentose or arachnoid-tomentose .........................................................................................................................10
- Stems pilose or hirsute-articulate .....................................................................................................................................................11
10. Basal and lower cauline leaves pinnatisect or pinnatipartite; involucres 30–35 mm long; appendages dark brown or blackish, 3–4 mm wide at base (cilia excluded); terminal spine 8–18(–22) mm long; achenes 5–5.2 mm long; pappus 6.5–7 mm long ................ .................................................................................................................................................................................... C. orumiehensis
- Basal and lower cauline leaves lyrate; involucres (30–)35–40(–45) mm long; appendages straw-coloured or pale brown, 6–9 mm wide at base (cilia excluded); terminal spine 20–30(–40) mm long; achenes 6–7 mm long; pappus (8–) 9–14 mm long................... .............................................................................................................................................................. C. urvillei subsp. deinacantha
11. Pappus 13–15 mm long .................................................................................................................................................. C. luristanica
- Pappus 6–9(–11) mm long................................................................................................................................................................12
12. Appendages straw-coloured .............................................................................................................................................................13
- Appendages brown or dark brown ...................................................................................................................................................14
13. Involucres (20–) 25–30 mm wide; appendages (5–) 6–7 mm wide at base (cilia excluded); terminal spine 21–30(–35) mm long; cilia (10–)12–15 on each side, 6–9 mm long .................................................................................................................... C. ochrocephala
- Involucres 16–23 mm wide; appendages 4–5 mm wide at base (cilia excluded); terminal spine 10–20(–27) mm long; cilia 8–10 on each side, (3–)4–5(–6) mm long.......................................................................................................................................... C. persica
14. Basal leaves 30–42 cm long; appendages brown or light brown, 1.5–2.5 mm wide at base (cilia excluded); cilia 5–8 on each side; achenes ca. 5 long........................................................................................................................................................ C. khosraviana
- Basal leaves 10–20 cm long; appendages dark brown, blackish or brown, 4–8 mm wide at base (cilia excluded); cilia (8–)10–13 on each side; achenes 5.5–6 long .....................................................................................................................................................15
15. Stems usually branched from lower to upper parts; terminal spine of median appendages 20–30 mm long .............. C. sintenisiana
- Stems branched in median or upper parts; terminal spine of median appendages (5–)10–15(–20) mm long .................................16
16. Plants biennial; basal and lower cauline leaves pinnatisect, with up to 10 lateral segments; involucres 30–35 × 30–35 mm; appendages 5–8 mm wide at base (cilia excluded); pappus 10–11 mm long............................................................ C. elegantissima
- Plants perennial; basal and lower cauline leaves lyrate, with 2–4 lateral segments; involucres 20–25 × (15–)18–22(–25) mm; appendages 3–5 mm wide at base (cilia excluded); pappus 6–9 mm long (C. pseudoscabiosa) .....................................................17
17. Terminal spine of appendages 10–15(–20) mm long ..................................................................... C. pseudoscabiosa subsp. armata
- Terminal spine of appendages (2–)3–6(–8) mm long.......................................................................................................................18
18. Involucres narrower, 14–17 mm wide; appendages small, ca. 2 mm wide at base (excluding cilia); cilia 1.5–2(–2.5) mm long....... .................................................................................................................................................... C. pseudoscabiosa subsp. araratica
- Involucres broader, 20–30 mm wide; appendages medium-sized, 3–4 mm wide at base (excluding cilia); cilia (2–) 3–5 mm long .. ..........................................................................................................................................................................................................19
19. Plant 40–90 cm tall; stems branched in upper part........................................................... C. pseudoscabiosa subsp. pseudoscabiosa
- Plant up to 35 cm tall; stems simple or branched from near base .................................................. C. pseudoscabiosa subsp. glehnii
description: Published as part of Negaresh, Kazem, Yousefi, Zohreh & Kaya, Yusuf, 2023, A new species of Centaurea sect. Acrocentron (Asteraceae, Cardueae) from Iran, pp. 37-50 in Phytotaxa 597 (1) on page 44, DOI: 10.11646/phytotaxa.597.1.5, http://zenodo.org/record/7918782