Cyathea planadae N.C.Arens & A.R.Sm., Amer. Fern J.

Lehnert, Marcus & Kessler, Michael, 2018, Prodromus of a fern flora for Bolivia. XX. Cyatheaceae, Phytotaxa 334 (2), pp. 118-134 : 129

Cyathea planadae N.C.Arens & A.R.Sm., Amer. Fern J. 88: 50. 1998.

= Cyathea xenoxyla Lehnert, Amer. Fern J. 93: 175. 2003, syn. nov.

Range: —Andes from Colombia to Bolivia (CO, LP).

Ecology: —Uncommon in the understory of wet montane rain forests, tolerating opening of the canopy by tree fall gaps but no exposure by clear cutting; regularly found but never in large numbers; 1900–2500 m.

Notes: —The original description claims that C. planadae reproduces by stolons ( Arens & Smith 1998). However, our observations at the type locality show this not be the case. Rather, the species has adventitious buds along its trunk that grow new erect trunks when the old main trunk has fallen over. At the type locality in southeastern Colombia, we observed the highest number of C. planadae plants in the spots where large branches had broken off trees, flattening the vegetation below. Futhermore, we observed a correlation between humidity, density of the vegetation and trunk diameter throughout the range of the species, with only slender trunks being produced when humidity is high and the understory dense, and much thicker trunks found on relatively dry slopes and/or higher elevations where mean temperatures are lower, as in the type of the synonymous C. xenoxyla . As thinner trunks tend to topple over more easily than thicker ones, populations with the former have more individual plants than the latter, thanks to the vegetative reproduction. Further differences observed among specimens of C. planadae likely relate to environmental factors and subsequent growth speed, i.e. large plants with thick trunks have a higher density and larger size of prickles than smaller ones, and also a thicker layer of scales covering the crozier; this means that darker scales from the outer crozier layer do not persist in the scaly laminar indument, like they often do on the fronds axes of smaller fronds.