The cell wall is one of the defining characteristics of plants and is a fundamental component in normal growth and development. Cell wall composition is a potentially valuable source of phylogenetic information as notable similarities and differences exist between and within major embryophyte groups. In particular, there is a pronounced chemical demarcation between the eusporangiate pteridophytes (high mannan, low tannin) and the leptosporangiate pteridophytes (low mannan, high tannin). The results of recent biochemical and immunocytochemical investigations have shown that changes in cell wall composition accompanied the bryophyte–lycopodiophyte and eusporangiate–leptosporangiate transitions.
With the aim to establish a conservation plan for the endangered Trichomanes speciosum Willd. in northwestern France, the “Conservatoire Botanique National” of Brest has carried out field work to collect appropriate information about this species. In particular, the data available about the type of habitat, abundance and ecology, as well as the threats for the gametophyte and sporophyte stages, were updated.
Ferns with a tree habit are mainly found in the families Cyatheaceae and Dicksoniaceae. Together, they constitute a diverse pantropical group of common to locally dominant elements of tropical floras, especially in montane forests. Many species have very restricted distribution ranges and some are highly threatened. Taxonomic understanding of these ferns, a prerequisite to successful establishment of conservation strategies, is hampered by the disparate and often insufficient quality of available herbarium material. During recent fieldwork, a time-efficient scheme has been developed permitting to maximize the information content of tree fern collections. A simple non-destructive silicone moulding method to preserve important characters of the trunk surface is introduced. A standardized annotation sheet as a field book supplement is provided along with a summary sheet of the presented collecting approach for quick reference in the field. Standardized annotations and associated collections such as stem moulds greatly augment the value of the specimen.