Hysterionica Willdenow 1807
Creators: name: Deble, Leonardo Paz
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Asterales
Asteraceae
Hysterionica

description: Key to South American species of Hysterionica   
1. Leaves with margin entire (rarely the most basal leaves with margin few toothed)..........................................................................2  
- Leaves with margin irregularly incise-toothed, or deeply lobed.................................................................................................... 14  
2. Annual herbs.......................................................................................................................................................................................3  
- Perennial herbs or subshrubs..............................................................................................................................................................4  
 3. Ray flowers 1–2-seriate, corolla white.............................................................................................................. Hysterionica resinosa   
 - Ray flowers 3–4-seriate, corolla yellow............................................................................................................... Hysterionica bakeri   
4. Basal leaves in rosulate leaf arrangement, sometimes become dry at the end of the anthesis...........................................................5  
- Leaves distributed uniformly along the stem.................................................................................................................................... 9  
5. Pulvinate dwarf subshrubs. Ray flowers with white corolla. Cypselae fusiform or oblong-fusiform, not compressed or slightly compressed, 4–7-ribbed......................................................................................................................................................................6  
- Perennial herbs. Ray flowers with yellow corolla. Cypselae compressed, with two lateral ribs.......................................................7  
 6. Leaves 15–60 × 1–3 mm, adaxial surface pubescent.................................................................................. Hysterionica dianthifolia   
 - Leaves 4–15 × 0.3–0.9 mm, adaxial surface glabrous.................................................................................... Hysterionica pulvinata   
 7. Leaf-blades sericeous-pubescent..................................................................................................................... Hysterionica pulchella   
- Leaf-blades sparsely pubescent, trichomes not applied to surface.....................................................................................................8  
 8. Pappus composed by 2-series of bristles................................................................................... Hysterionica aberrans var. hunzikeri   
 - Pappus composed by a unique series of bristles........................................................................... Hysterionca aberras var. aberrans   
9. Leaves often lanceolate or elliptic in shape, 1.5–6 mm wide. Cypselae 2–4-ribbed.......................................................................10  
- Leaves often filiform or linear in shape, 0.4–2 mm wide. Cypselae 4–10-ribbed...........................................................................12  
 10. Plants seemingly glabrous. Leaves grayish-green, rigid in texture............................................................... Hysterionica glaucifolia   
- Plants with abundant filiform trichomes. Leaves thin in texture......................................................................................................11  
 11. Leaves covered by hispid trichomes, 1.5–4 mm long. Outer pappus composed by filiform bristles, 1.5–2 mm long.............................................................................................................................................................................................. Hysterionica jasionoides   
 - Leaves covered by strigose trichomes, thickened at base, 0.3–1 mm long. Outer pappus composed by scales, 0.4–0.8 mm long.............................................................................................................................................................................. Hysterionica cabrerae   
 12. Ray flowers with white corolla. Outer pappus composed by a crown of scales, 0.5–1 mm long. Cypselae obovate, slightly compressed, 4–5-ribbed, 0.8–1.4 mm long........................................................................................... Hysterionica chamomilloides   
- Ray flowers with yellow corolla. Outer pappus composed by few bristles. Cypselae obovate-fusiform, 7–10-ribbed, 1.4–2.8 mm long...................................................................................................................................................................................................13  
 13. Ray flowers 3–4-seriate. Leaves with abundant hispid trichomes; blades linear-filiform, at base truncate, 0.6–1 mm wide...................................................................................................................................................................................... Hysterionica filiformis   
 - Ray flowers 1–2-seriate. Leaves with absent or scarce trichomes; blades linear-oblong or linear-lanceolate, at base semiamplexicaul, 1–2 mm wide............................................................................................................................... Hysterionica pinifolia   
 14. Leaves with margin irregularly incised-toothed. Outer pappus composed by few scales (ca. 2–4).................................................................................................................................................................................................................... Hysterionica matzenbacheri   
 - Leaves with margin deeply lobed. Outer pappus composed by a crown of scales (ca. 6–8)...........................................................15   
15. Leaves densely hairy, segments slightly acute, obtuse or rounded..................................................................................................16  
 - Leaves glabrous or with scarce sericeous trichomes, segments acute or acuminate.................................. Hysterionica pinnatisecta   
 16. Leaves with segments linear-oblong, 5–10 × 0.8–1.5 mm. Ray flowers 12–15 mm long, much exceeding the involucre.......................................................................................................................................................................................... Hysterionica nebularis   
 - Leaves with segments obovate or elliptic, 5–15 × 2–5 mm, Ray flowers 6–8 mm long, slightly exceeding the involucre...................................................................................................................................................................................... Hysterionica pinnatiloba
description: Published as part of Deble, Leonardo Paz, 2021, Hysterionica chamomilloides (Asteraceae: Astereae) a new species from the grassland ecosystem of Río de La Plata, pp. 36-44 in Phytotaxa 482 (1) on pages 41-42, DOI: 10.11646/phytotaxa.482.1.4, http://zenodo.org/record/5417994