Herbertia, Sweet, 1827

Deble, Leonardo Paz, 2022, Herbertia guyunusae, a new species of Iridaceae from the grassland ecosystem of Río de La Plata, South America, Phytotaxa 570 (1), pp. 55-66 : 61-62

Key to the species of Herbertia

1. Inner tepals with white and dark purple longitudinal stripes, apex rounded to truncate, not revolute. Anthers shorter than 3 mm long.......................................................................................................................................................................... Herbertia zebrina

- Inner tepals without longitudinal stripes, apex obtuse to acuminate, revolute or shortly uncinate. Anthers 3 mm long or more … 2

2. Filaments entirely united in column, anthers attached directly to the column...................................................................................3

- Filaments free for 1–4 mm long at the apex, anthers attached to the filament...................................................................................8

3. Secondary divisions of style branches straight, emarginated or shortly bifid for 0.1–1.2 mm. Ovary oblong, 8–15 mm long. Capsules 18 mm long or more............................................................................................................................................................4

- Secondary divisions of style branches recurved, bifid for 1.2–4 mm. Ovary obovate, 4–9 mm long. Capsules up to 18 mm long ... ............................................................................................................................................................................................................5

4. Leaves lanceolate or elliptic-lanceolate, 4–10 mm wide. Spathes 1-flowered. Outer tepals broadly spathulate, obovate or obdeltate, 8–14 mm wide. Inner tepal with a dark-blue transverse stripe at top of the central depression ................................ Herbertia lahue

- Leaves linear, 2–3 mm wide. Spathes 2-flowered. Outer tepals oblanceolate, 5–7 mm wide, markedly pandurate. Inner tepal with a yellow and purple spotted transverse stripe at top of central depression ............................................................ Herbertia amoena

5. Flowers without yellow stains. Inner tepals with periphery of central depression violet-blue or blue, rarely with few white spots .. ............................................................................................................................................................................... Herbertia caerulea

- Flowers with outer and/or inner tepals with yellow stains. Inner tepals with a yellow spot on both sides of the periphery of the central depression ..............................................................................................................................................................................6

6. Outer tepals with abundant dark-violet spots, covering the claws and the proximal half of the blade, blade without yellow stains. Inner tepals triangular, at apex acute. Style branches horizontal or slightly patent, with secondary divisions bifid for 1.2–1.8 mm. .......................................................................................................................................................................... Herbertia tigridioides

- Outer tepals with a yellow central stripe at the base of the blade. Inner tepals abruptly narrowed at apex, acuminate. Style branches ascending or erect-ascending, with secondary divisions of style branches bifid for 1.8–4 mm ........................................................7

7. Leaves linear-lanceolate or elliptic-lanceolate, ca. 10 mm wide. Inner tepals oblanceolate or elliptic-lanceolate, 3–5 mm wide ..... ............................................................................................................................................................................... Herbertia darwinii

- Leaves narrowly linear, ca. 5 mm wide. Inner tepals narrowly oblanceolate, 1.4–2 mm wide ....................................... H. amabilis

8. Outer tepals with one-celled lipidic trichomes forming a dense carpet extending along the claw and ending near at the base of the blade ...................................................................................................................................................................................................9

- Outer tepals with one-celled lipidic trichomes absent or few, scattered near at the base of the blade.............................................11

9. Outer tepals horizontal or slightly patent, with carpet of one-celled lipidic trichomes spreading in a triangular area. Filaments free at apex for 1–1.5 mm. Anthers 4–5 mm long........................................................................................................... Herbertia crosae

- Outer tepals recurved, with carpet of one-celled lipidic trichomes spreading in a heart-shaped area. Filaments free at apex for 2.5–4 mm. Anthers 6–8 mm long ...............................................................................................................................................................10

10. Inner tepals oblanceolate, 2.5–3.5 mm wide, central concavity with scarce one-celled lipid trichomes, spreading on two lateral bands..................................................................................................................................................................... Herbertia pulchella

- Inner tepals oblong, ca. 2 mm wide, central concavity densely covered by one-celled lipidic trichomes ........ Herbertia amatorum

11. Plants robust, up to 35 cm high. Leaves linear-lanceolate or elliptic-lanceolate, 6–15 mm wide. Flowers 6–7 cm in diam. Inner tepals oblanceolate or elliptic-lanceolate, 5–6 mm wide, acuminate at apex................................................... Herbertia quareimana

- Plants delicate, up to 15 cm high. Leaves linear, 1–2 mm wide. Flowers 3–4 cm in diam. Inner tepals oblong, 2–3 mm wide, obtuse or slight acute at apex ........................................................................................................................................ Herbertia guyunusae