Ptisana, Murdock, 2008

Key to the species of Ptisana in Africa and surrounding islands

1. Pinnule veins curved. Synangia perfectly marginal, almost in the teeth of the margin. (swamps in Guinea)......................... .................................................................................................................................................................. Ptisana odontosora

-. Pinnule veins straight. Synangia more than 1 mm from the margin ...................................................................................... 2

2. Very large plants (leaves> 3 m, petiole> 1.5 m on mature individuals), with trunk-like rhizomes (> 30 cm high), laminae with at least 6 pairs of pinnae ................................................................................................................................................ 3

-. Medium sized to relatively small plants (leaves <3 m long, petiole <1.5 m on fully mature individuals), with hemispherical rhizomes (<30 cm high), laminae with less than 5 pairs of pinnae (rarely more and then just on a few leaves, see P. fraxinea ) ................................................................................................................................................................................ 4

3. Broadly winged pinna rachises between the terminal pinnules and the last 5–8 juga. Distal pairs of pinnules mostly gradually and evidently smaller than the others. Terminal pinnules longer and often pinnatifid or pinnatipartite at the base. ( South Africa, Zimbabwe, Malawi and Mozambique) ................................................................................ Ptisana salicifolia

-. Pinna rachises not winged or at most with narrow wings distally up to the 1–2 distal pairs of pinnules. Distal pairs of the same size as the others. Terminal pinnules similar to the lateral ones. ( Guinea, Ethiopia, Kenya, Democratic Republic of Congo) ................................................................................................................................................................ Ptisana sp. A

4. Synangia median, situated at midway between the margin and the costa. Pinnule apices rounded or progressively narrowed, not acuminate. ( Madagascar incl. Île de Sainte-Marie) ....................................................................... Ptisana boivinii

-. Synangia marginal, situated at 1–2 mm from the margin. Pinnule apices acuminate............................................................ 5

5. Pinna rachises prickly ( São Tomé)................................................................................................................. Ptisana robusta

-. Pinna rachises not prickly ...................................................................................................................................................... 6

6. Pinnule blades thick, fleshy, leathery. Pinna rachises thick, robust. ( Ascension Island) ...................... Ptisana purpurascens

-. Pinnule blades more or less thick but never fleshy. Pinna rachises not robust ..................................................................... 7

7. Relatively small plants, petioles up to 60 cm. Pinnules at most 3 times longer than wide, with the apex abruptly caudateacuminate. ( Cameroon, Equatorial Guinea, Gabon) ........................................................................................... Ptisana sp. B

-. Medium sized plants, petioles generally more than 1 m. Pinnules more than 3 times longer than wide, with the apex progressively acuminate ............................................................................................................................................................. 8

8. Plants with a broad elevational range, from sea level upward. Secondary rachises at most slightly winged distally (except occasionally in juvenile plants). Terminal pinnules always similar to the other ones. ( Madagascar, Mascarenes)................. ........................................................................................................................................................................ Ptisana fraxinea

-. Plant exclusively in montane forests. Secondary rachises strongly winged on most of their length. Terminal pinnules often irregularly pinnate distally. ( Seychelles) ........................................................................................... Ptisana laboudalloniana