Aim of the study: The effect of cerium oxide engineered nanoparticles on the spore germination of the fern Asplenium adiantumnigrum.Area of study: France, Britanny Region, Finistére Department, Plougonvelin, in rocks near the sea. Material and methods: Asplenium spores were cultured in vitro on agar medium with Nano-CeO 2 (less than 25 nm particle size) and bulk-CeO 2 . The addition of each nano-and bulk particles ranged from 0 to 3000 mg L -1 . Observations on rhizoidal and prothallial cells during first stages of gametophyte development were made. The No-Observed-Adverse-Effect concentration (NOAEC) and Lowest-Observed-Adverse-Effect-Concentration (LOEC) values for spore germination rate data were analyzed.Main results: Germination was speeded up by 100 to 2000 mg L -1 nanoceria, while bulk cerium oxide had the same effect for 500 to 2000 mg L -1 concentrations. Present results showed cellular damage in the protonema while rhizoid cells seemed not to be affected, as growth and membrane integrity remained.Research highlights: Both nanosized and bulk cerium oxide are toxic for the fern Asplenium adiantum-nigrum, although diverse toxicity patterns were shown for both materials. Diverse toxic effects have been observed: chloroplast membrane damage and lysis, cell wall and membrane disruption which leads to cell lysis; and alterations in morphology and development.

Gametophytes of the Pteridaceae are moderately well known but there is still a quite large set of species to describe. Among these is Doryopteris triphylla, a member of the cheilanthoid clade (subgroup hemionitids). The main objective of this work is to describe the gametophyte of D. triphylla. In vitro cultures were prepared with spores coming from various sporophytes of different locations. In vivo observations were done periodically to monitor developmental critical events and reproductive activity. Germination followed the Vittaria pattern and the developmental processes adjusted to the Adiantum type. Adult cordate gametophytes produced normal sexual organs in unisexual prothalli. Doryopteris triphylla gametophytes exhibited somewhat peculiar features: the apical cell divided longitudinally, the first meristematic cell was rectangular, and archegoniate prothalli appeared much before than antheridiate ones.

En este artículo se incluye la primera parte del atlas de flora alóctona de la Comunidad de Madrid, que incluye los taxones de helechos y gimnospermas. Únicamente se han considerado taxones que crecen fuera de zonas urbanas, parques y jardines, tanto introducidos como naturalizados. En total se han analizado 49 taxones, 2 de helechos y 47 de gimnospermas (33 Pinaceae y 14 Cupressaceae). De ellos, se han considerado 34 taxones (1 Salviniaceae, 22 Pinaceae, 11 Cupressaceae) incluyendo mapas de distribución, mientras que en otros 15 su presencia es dudosa en la actualidad o están únicamente localizadas en zonas urbanas. Dominan las especies de Pinaceae como resultado de las plantaciones forestales realizadas. Buena parte de las especies consideradas tienen capacidad para naturalizarse (se tiene constancia en 19 de ellas), pero por lo general su capacidad de expansión es limitada, no siendo invasoras; únicamente Azolla filiculoides Lam. tiene un comportamiento invasor, aunque su distribución en Madrid parece estable.