Biology Reference
In-Depth Information
the presence of a unilateral scale is frequent in the position of the so-called
disc (Kårehed, 2001); it may be a receptacular nectary, as could be the case
in
Phyllonomaceae
that has a disc as well (Kårehed, 2001).
Apiales.
Ovarian nectaries are dominant in this order. In
Apiaceae
(Brown,
1938; Cronquist, 1981; Smets, 1986) and
Araliaceae
(Cronquist, 1981; Erbar
& Leins, 1988; Vezza et al., 2006), families with inferior ovaries, the ovary
roof (called stylopodium) is a gynoecial nectary originating from the dorsal
base of the carpel primordia (Erbar & Leins, 1995), which is delimited from
the styles by a groove at their base. In the two families with superior ovaries,
the situation is different:
Pittosporaceae
possesses a gynoecial nectary with
a similar origin to that in Apiaceae and Araliaceae, but located at the base of
the ovary in their external wall (Fahn, 1979; Erbar & Leins, 1995), whereas
Pennantiaceae
has neither stylopodia nor nectaries (Kårehed, 2003). Stylo-
podia are present in
Aralidiaceae
,
Mackinlayaceae
, and
Myodocarpaceae
(Kårehed, 2003) and they seem to be nectariferous. The remaining fami-
lies—
Griseliniaceae
,
Melanophyllaceae,
and
Torricelliaceae
—have no
stylopodia (Kårehed, 2003) and probably no nectaries, although Griselini-
aceae has a so-called disc that might be nectariferous.
Asterales.
Ovarian nectaries are the rule in this group. In
Alseuosmiaceae
, a
gynoecial nectary is found as a ring on top of the inferior to semi-inferior
ovary, although it may be absent (Cronquist, 1981; Lundberg & Bremer,
2003), as happens in
Argophyllaceae
(Lundberg & Bremer, 2003); on the
other hand, these nectaries seem to be missing in
Phellinaceae
, but present
in
Rousseaceae
(Lundberg & Bremer, 2003). In
Asteraceae
, nectaries are
ovarian and epigynous on top of the inferior ovary surrounding the style
base (see “Asteraceae” on page 46 for a detailed discussion; Brown, 1938;
Frey-Wyssling, 1955; Galetto, 1995c; Torres, 1998; Vogel, 1998c; Mani &
Saravanan, 1999; Bernardello et al., 2000; Sancho & Otegui, 2000; Ma et al.,
2002; Visintín & Bernardello, 2005; Wist & Davis, 2006). In
Calyceraceae,
nectaries are formed by stamens and petals: in five areas alternating with the
stamens, the nectariferous tissue extends from the base of the filament tube
to the top of the stamen-corolla tube (Erbar, 1993). In
Campanulaceae
(in-
cluding Lobeliaceae),
Lobelia
has complex nectar spurs involving both
perianth whorls and associated portions of the androecium and gynoecium
(Koopman & Ayers, 2005). Most genera have a voluminous ovarian nectary,
forming a ring around the free part of the semi-inferior ovary and, occasion-
ally, extending towards the hypanthium (Fahn, 1979; Cronquist, 1981; Smets,
1986; Erbar & Leins, 1989; Galetto et al., 1993; Vogel, 1998c; Anderson
et al., 2000a). In
Goodeniaceae
, there are one or two nectaries on the top of
the ovary, with bilateral symmetry (Cronquist, 1981; Leins & Erbar, 1989).
