EPIDERMIS AND STOMATOGENESIS :MARIATTIACEAE (MARATTIALES-EUSPORANGIOPSIDA)

Abstract

The present paper is the first analysis of the epidermic morphology and the stomatogenesis of 8 species of eusporangiate fems, belonging to Angiopteris Hoffmann, Darwea J. B. Smith and Marattw Sw. In the first case we have taken into accowlt epidermal cells as seen from the urface, mature stomata, trichomas, scales and silica ceIls, and have found that diagnostic traits, down to tIle specific level, can be discemed out of them. The indument is here studied for the first time, revealing trichomas that can be non-glandular ane! massive or glandular (taniferous), and scales either inserted by their. bases 01' peltate. Stomatogenesis is also stlldied for the first time in 2 species: MarattúL alata Sw. and M. kaulfussíi ]. B. Smith. Development modes are two: perigenous and mesoperigenous, with predominance of the latter. Besides triads of the "'l' type, already described for Angiopteris evecta (Forster) Hoffmann, two other types are also found: (a) "parallel" and (b) "oblique", in which the guard cells are cut off by a second oblique división of the meristemoid. Both types are here described for the first time. A brief discussion follows, concerning the most convenient Spanish temlinology for stomatal apparatuses, and its correspondence to English terms. The use of the above characters allows for a clear separation of the 8 species under study, and for an "a priori" pointing of affinities among genera. The epidermic morphology would be in agreement with Copeland's 1947 sllggestion about a doser reJation between Angiopteris and Marattia than between both and DmUlea, and with the idea of Pant et al. (1983) that the extant genera of the Order Marattiales should naturally falt into only one family: Marattiaceae.