Biology Reference
In-Depth Information
some cases, the nectaries are found on the petal claws (Kerner von Marilaun
& Oliver, 1895), and in other cases nectar was found around the base of the
ovary (Lowrie, 2001), so there is no certainty on the exact place of nectar
secretion. In
Frankeniaceae
, the five long-clawed petals have five nectar-con-
taining chambers formed by scales on the inner side, forming revolver-type
flowers (Brochmann et al., 1995). In
Molluginaceae
, the site of nectar pro-
duction is the staminal tube of the inner stamens, where the nectariferous
tissue lines the inner surface and the region where the staminal tube is adnate
to the ovary. In some taxa nectariferous tissue may form a ring surrounding
the ovary (Zandonella, 1977). In
Nepenthaceae
, Kato (1993) recorded nec-
taries wholly distributed on the adaxial surface of the sepals. In
Nyctaginaceae
, the nectariferous tissue is normally located basally on the
adaxial surface of the staminal tube (Zandonella, 1977; Vanvinckenroye
et al., 1993; López & Galetto, 2002). In
Phytolaccaceae
, which is considered
by Zandonella (1977) to be the basal type, the receptacle is nectariferous and
forms an intrastaminal ring, either between the inner whorl of stamens and
the ovary, or at the base of the inner stamens (Zandonella, 1977; Bernardello
et al., 1993); however, no nectar-secreting tissue was found in Rivinoideae
(Zandonella, 1977). In
Plumbaginaceae
, the nectaries are always associated
with the androecium, mainly with the stamen bases (Galetto, 1993; De Laet
et al., 1995).
Polygonaceae
also has receptacular nectaries between the sta-
men bases and the ovary (Decraene & Smets 1991a; De Melo et al., 2003).
Decraene and Smets (1991a) distinguished two nectary types: in Persicarieae
there are conspicuous nectar-secreting structures (free or variously fused),
whereas in Polygoneae nectarial zones are not developed externally. These
authors suggested a centrifugal shift of the nectaries, from a
Rheum
-like an-
cestor with intrastaminal annular nectaries, through a
Fagopyrum
-like
ancestor with free nectaries, to the nectaries of Polygoneae and Persicarieae
listed above.
Portulacaceae
possesses nectaries on the adaxial base of the
stamens (Zandonella, 1977; Vanvinckenroye & Smets, 1996, 1999). Finally, in
Tamaricaceae
there is a fleshy receptacular nectary where petals, sepals, and
stamens are seated, or it may be intrapetalar or intrastaminal (Brown, 1938;
Fahn, 1979; Cronquist, 1981); the scales of the petals are not nectariferous
(Decraene, 1990).
Santalales.
This parasitic order has receptacular nectaries, or if the ovaries
are inferior, nectaries are located on the top part of the ovary. In the litera-
ture, the nectaries are mostly referred to as discs (e.g., Kjuit, 1969; Cronquist,
1981), and sometimes there is no direct evidence that they secrete nectar, a
circumstance that should be investigated.
Loranthaceae
is most often bird-
pollinated and flowers produce large amounts of nectar (Kjuit, 1969; Galetto
et al., 1990; Aizen, 2005). The nectary is usually located at the top of the
