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65 The naming of organisms (and plant communities)
dot, [.]:(phyl., prop.) proposed as a method of indicating a converted
species name in phylogenetic nomenclature, e.g. Sturnus.vulgaris;
see also hyphen.
double citation: (unoff.) an author citation in which the author of an epithet
or name is placed in parentheses, followed by the citation of the
author who moved it to its current position and rank, as in a new
combination (q.v.).
double cross: (cult. pl.) the repeatable crossing of two F1 hybrids.
double name: (phyt.) the name of a syntaxon composed of the names of
two subordinate syntaxon names; when each is confined to either of
the two syntaxa of the next subordinate principal rank that are
named in the original diagnosis of the superior syntaxon, the name
cannot be retained when a division of the superior syntaxon
separates the subordinate syntaxa.
doubtful name: (prok.) a dubious name (q.v.).
dubiotype: see incognitotype.
dubious name, [nomen dubium, nom. dub.]: a name of unknown or
doubtful application; e.g. because of a lack of original or type
material and sufficient information about it to make a satisfactory
typification possible, or because it is impossible to ascertain to
which taxon its type should be referred; a doubtful name (prok.)
ducotype: (zool., unoff.) a type with the head of one species glued onto the
body of another (!); a gluotype (q.v.).
duplicate: (bot.) part of a single gathering of a single species or
infraspecific taxon made by the same collector (or collectors) at one
time.
duplotype: (1) (zool., unoff.) a second holotype for the same taxon. (2)
(zool., unoff.) a single specimen used as holotype for two different
taxa; a redundotype (q.v.) for the later described; see also triplotype.
DUS test: (cult. pl.) the criteria of Distinctness, Uniformity and Stability by
which a new cultivar is examined for statutory purposes such as for
the granting of Plant Breeders’ Rights.