DARWINIANA
34(1-4): 1-17. 1996
MORFOLOGIA DE LAS INFLORESCENCIAS EN VERBENACEAE-VERBENOIDEAE.
I: TRIBU VERBENEAE
SUSANA MARTINEZ 1
Facultad de Ciencias Exactas y Naturales, Universidad de
Buenos Aires, Ciudad Universitaria, Pabellón II 4º Piso. (1428) -Buenos
Aires, Argentina.
SILVIA BOTTA+ y MARIA E.MULGURA2
Instituto de Botánica Darwinion, C.C. 22, (1642) - San Isidro.
Argentina.
ABSTRACT: Martínez, S., Botta, S. and Múlgura, M.E. 1996. Morphology
of Inflorescences in Verbenaceae-Verbenoideae. I: Tribe Verbeneae. Darwiniana
34: 1-17.
This paper deals with the interpretation, description and typological
characterization of the inflorescences of the genera belonging to the tribe
Verbeneae. These genera are: Glandularia Gmelin, Hierobotana
Briquet, Junellia Moldenke, Tamonea Aublet, Verbena
Linné and Urbania R.
A. Philippi, all of them represented in South America.
All the cases belong to the polytelic type of synflorescences. Florescences
of almost all genera are dense spikes with decussate bracts. Only Tamonea has loose, spiciform
racemes with disperse bracts. Floral prophylls are always absent.
The heterothetic pleiobotryum is the most frequent branching form,
present in Verbena, Glandularia and Hierobotana. Urbania
and Junellia have monobotrya. Homothetic pleiobotrya characterize
all species of Tamonea. Heteroblastic development of the branches
can be observed in several species of Junellia. In these
cases flowering can be restricted to the brachyblasts; a frequent specialization
in woody plants.
The heterothetic paniculiform pleiobotryum has been mentioned for several
families of the Angiospermae as a primitive or central form, from
which other forms derived through processes such as condensation, reduction
and truncation. In Verbeneae this non specialized "paniculodium"
is present in Verbena and Glandularia. Condensation of the
florescences, to compose more or less functionally discrete subunits, appears
in Verbena Ser. Pachystachyae and Glandularia Subgen.
Paraglandularia.
Reduction of the enriching zone occurs in Urbania and most Junellia
species. Such reduction and decrease of flower number in the florescences
could be related to the xerophyllous nature of these species. Truncation
of the main florescence, such as the homogenization and racemization of
the distal paracladia, have been produced in Tamonea giving rise
to an homothetic pleioraceme. Tamomonea shows few affinities with
the remaining genera of Verbeneae. It differs from them in several
inflorescence characters and gynoecial features previously studied by other
authors. Because of all these characters, the place of this genus within
the Verbenoideae should be reconsidered.
1 Cátedra de Morfología Vegetal
2 Miembro de la Carrera de Investigador Científico
y Tecnológico del CONICET.