The invaluable commented checklist of the vascular flora of the ultramafic
rocks of northeastern Portugal of Pinto da Silva (1970) has been recently reviewed
by Aguiar and Monteiro-Henriques (ined.). These authors’ accept 568 taxa, 29% of
which (164 taxa) are new additions to the original catalogue of Pinto da Silva (1970).
A subset of it with the most frequent and floristically relevant species is presented
in Table 6. New additions have been highlighted with an asterisk (*). The most noticeable
neophytes have been included and marked with an open rhombus (◊). A
few synonyms have been added to facilitate the reading of the list of Pinto da Silva
(1970). Familiar circumscription and higher taxa are according, respectively, to APG
III (2009) and Chase & Reveal (2009). The main sources of infrafamiliar taxonomic information
were the Flora Iberica (Castroviejo 1981+), Nova Flora de Portugal (Franco
1971; 1984; Franco & Rocha Afonso (1994; 1998), The Checklist of the Portuguese
Vascular Flora (Sequeira et al. 2011) and, among others, the taxonomic revisions of
Romero et al. (1988) (Agrostis), Díaz Lifante & Valdés (1996) (Asphodelus), La Guardia
& Blanca (1987) (Scorzonera), Schippmann (1991) and Voght (1991) (Leucanthemum).
We followed different taxonomic or nomenclatural criteria from Flora Iberica
or Nova Flora de Portugal in Armeria langei subsp. marizii, Anthyllis sampaioana,
A. vulneraria subsp. lusitanica, Alyssum serpyllifolium subsp. lusitanicum, Asplenium
adiantum-nigrum subsp. corunnense, Carlina hispanica, Centaurea langei, Festuca elegans
subsp. merinoi, Helianthemum apenninum subsp. rothmaleri, Tuberaria guttata
and Trifolium striatum var. brevidens.
The preparation of a checklist of ultramafic vascular flora is a difficult task. First
of all, flora checklists are unfinished assignments because plants come and go with
time. On the other hand, the northeastern Portugal ophiolites lithology is heterogeneous
and complex. Peridotites, and similar ultramafic rocks, appear in stretched
outcrops dispersed among macromorphologically similar basic rocks. The soils that
have covered the ultramafic rocks many times catch materials from nearby mafic
and leucocratic rocks. Finally, deep soils, rich in organic matter, derived from ultramafic
rocks, usually have a similar flora to other nearby lithologies. The serpentine
effect is in practice impossible to spatialize and quantify; consequently an ultramafic
vascular flora checklist brings together plants of rather diverse ecology, and is by
itself of limited scientific value.
