Ptisana sp. A

Senterre, Bruno, Rouhan, Germinal, Fabre, Isabelle, Morel, Charles & Christenhusz, Maarten J. M., 2014, Revision of the fern family Marattiaceae in the Seychelles with two new species and a discussion of the African Ptisana fraxinea complex., Phytotaxa 158 (1), pp. 57-75 : 71-72

Ptisana sp. A

Synonyms:— Marattia chevalieri Christ , nom. ined. (A. Chevalier 13445, P-00507739). Marattia fraxinea auct. non Sm., sensu Pichi-Sermolli (1969).

This species is typically found in Kenya and Ethiopia and it most likely extends into Rwanda, Burundi, Tanzania, Malawi, Mozambique and the Democratic Republic of Congo. After reviewing specimens from Guinea, Côte d’Ivoire and Sierra Leone, we have concluded that these specimens belong to the same species as P. fraxinea of Pichi-Sermolli (1969) from Ethiopia. Pichi-Sermolli also confirmed this by placing a determinavit ‘ Marattia fraxinea ’ on the specimen A. Chevalier 13445 (P). Ptisana sp. A has also been confused with P. odontosora by Chevalier, before the description of the latter, and consequently Christ included the material misidentified by Chevalier as syntypes for M. odontosora (see detailed explanation in Pichi-Sermolli 1969: 341–343), which explains why the name M. odontosora has been commonly used for specimens from tropical East Africa. Nevertheless , P. odontosora is a totally different species from marshes in the Fouta Djalon (Guinea). Considering that Pichi-Sermolli (1969) carefully studied Ptisana sp. A and identified its closest relative as P. salicifolia , and that he recognized it as distinct at species level, we suspect we are dealing with an undescribed species rather than as a subspecies of P. salicifolia . It differs from P. salicifolia by the “pinnae with rachis not winged or with a very narrow and straight wing between the terminal pinnule and the last two or three juga”, and by the “terminal pinnules similar to the lateral ones” (Pichi-Sermolli 1969: 336). As for other taxa in the Guinean region, the apices of pinnules are “gradually tapering and usually abruptly terminated by a long caudate point or sometimes ending with an acuminate tip” (Pichi-Sermolli 1969: 336, 349).

If only characters of pinnae are available, it is difficult to distinguish Ptisana sp. A from P. fraxinea , which explains why it has traditionally been confused with that species. Ptisana sp. A differs from P. fraxinea by its distal pairs of pinnules being similar in size and shape to the other ones (progressively larger distally for P. fraxinea ), the pinnules with a more or less abruptly caudate acuminate apex (progressively narrowed or acuminate for P. fraxinea ), a larger rhizome, up to 40 cm tall (up to 20 cm, hemispherical, for P. fraxinea ), leaves of 2.5–3.0 m long, up to 4 m ( Verdcourt 1999), petioles 0.9–1.2(–1.5) m (thus shorter than the lamina), with 6–9 pairs of pinnae.

Representative specimens examined:— GUINEA. Chevalier 12329 (P-01647448!), 17052 (P-01647426!). IVORY COAST. Chevalier 19685 (P-01647424!). SIERRA LEONE. Jaeger 6873 (P-01647431!). ETHIOPIA. Mooney 8809 (K). KENYA. P. Kamau & M.J.M. Christenhusz 638 (EA, K). DEMOCRATIC REPUBLIC OF CONGO. de Nere 2184 (P-01647389!).