Biology Reference
In-Depth Information
gynoecium, either annular or with upturned margins (in most Celastroideae).
It may (i) be located between the corolla and androecium (extrastaminal, in
Salacioideae, most Hippocrateoideae, some Celastroideae), (ii) extend on the
receptacle from the corolla to the gynoecium, or (iii) may form, with the
filament bases, a collar with broad interstaminal portions that have been in-
terpreted as staminodes (Simmons, 2004a; Matthews & Endress, 2005b). In
Lepidobotryaceae
, the intrastaminal receptacular nectary extends between
stamens and ovary, protruding between the filament bases, which form a col-
lar around the gynoecium (Link, 1991; Tobe & Hammel, 1993; Matthews &
Endress, 2005b). In
Parnassiaceae
no receptacular nectaries have been ob-
served, but nectaries have been interpreted as an inner androecial whorl of
staminodes because nectar is ventrally secreted from the pad of tissue bear-
ing the staminodial rays (Sandvik & Totland, 2003; Simmons, 2004b;
Matthews & Endress, 2005b).
Malpighiales.
Some families within the order bear no nectaries, such as
Balanopaceae
,
Elatinaceae
,
Goupiaceae
,
Hypericaceae
,
Lacistemata-
ceae
,
Lophopyxidaceae
,
Ochnaceae
,
Pandaceae
,
Peridiscaceae
,
Picro-
dendraceae
,
Podostemaceae
, and
Putranjivaceae
, which are either wind-
pollinated or have pollen flowers (Cronquist, 1981), while
Malpighiaceae
has typical oil flowers (Simpson & Neff, 1983; Sigrist & Sazima, 2004).
Other families are animal-pollinated and show mostly receptacular (intra- or
extrastaminal) nectaries, but also hypanthial and staminal. For
Achariaceae
,
Bernhard (1999a) found five antesepalous, extrastaminal, vascularized nec-
tary glands; as little secretion was found, however, there is doubt that they
are indeed nectaries. In
Bonnetiaceae
, intrastaminal nectarial glands alter-
nating with the stamen clusters at the base of the ovary have double bundles
similar to those of stamens (Dickinson & Weitzman, 1998). Based on the
vasculature of the nectaries, these authors are of the opinion that they repre-
sent transformed stamens. The presence of nectaries is variable in the genus
Archytaea
and this does not seem to follow a geographical pattern (Dickin-
son & Weitzman, 1998). In the mainly bat-pollinated
Caryocaraceae
,
nectariferous tissue was histologically observed surrounding the ovary base
(Dickinson, 1990), although previously it was reported to occur on the stami-
nodes (Prance & Freitas da Silva, 1973).
Chrysobalanaceae
has well-
developed hypanthia that are nectariferous (Cronquist, 1981; Arista et al.,
1997). The flowers of
Clusiaceae
offer either nectar, pollen, or resin as re-
wards for pollinators (Gustafsson & Bittrich, 2002). In nectar taxa, there are
either nectariferous scales or a cupular annular nectary; these have been con-
sidered staminodial (Robson, 1961), a presumption confirmed by Decraene
and Smets (1991b). In
Ctenolophonaceae
, the nectary is receptacular, extra-
staminal and annular, with the filament bases adnate to it, whereas in
