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have pollen as the pollinator reward. However, some singular species pos-
sess non-structural nectaries on the filaments of the stamens, which show
thickened vascular bundles (Stein & Tobe, 1989; Vogel, 1997). Alterna-
tively, petal nectaries on
Medinilla
and stigma nectaries in
Miconia
have
been recorded (Stein & Tobe, 1989; Vogel, 1997). Stein and Tobe (1989),
taking into account the ancestral myrtalean nectary type (structural, mostly
hypanthial), consider that structural nectaries were lost in the lineage ances-
tral to Melastomataceae; nectaries were acquired again with a different
structure and position, a fact correlated with a shift in pollinator interactions:
from buzz pollination by bees at lower elevations to vertebrate pollination in
higher elevations.
Myrtaceae
is typical for having nectaries on the inner part
of the hypanthium, on the top of the ovary, or on both (Cronquist, 1981;
O'Brien et al., 1996; Davis, 1997). In
Onagraceae
, the inner, basal part of
the hypanthium is commonly nectariferous (Cronquist, 1981; Eyde, 1981;
Smets, 1986). In some tubeless species, however, (e.g., species of
Circaea
,
Epilobium
,
Gayophytum
,
Gonylocarpus
,
Lopezia
), nectaries are receptacular,
on the appendage side of the junction of appendages and gynoecium or gy-
noecial and on the top of the ovary (as in
Ludwigia
), either sunken or raised,
with trichomes on their epidermises or without them (Eyde, 1981, 1982);
staminal nectaries in
Lopezia
were also reported (Eyde, 1982). In
Vochysi-
aceae
, nectariferous sepal spurs have been observed, with nectar produced
directly on the spur (Oliveira, 1996; Hodges, 1997). Concerning
Alzateaceae
,
Oliniaceae
,
Penaeaceae
, and
Rhynchocalycaceae
, there is a recent survey
of floral morphology, but unfortunately, there is no mention of the presence
of nectaries (Schönenberger & Conti, 2003). These families possess a hypan-
thium and it may be nectariferous, as in other members of the order.
3.8.10
Eurosids I
The Eurosid I clade has some members without nectaries. When present,
nectaries are predominantly receptacular (mostly intrastaminal), followed by
hypanthial and staminal nectaries; sepal, petal, and gynoecial nectaries are
more rare. In
Zygophyllaceae
, there is a continuous intrastaminal receptacu-
lar nectary located around the base of the ovary (Cronquist, 1981; Decraene
et al., 1996; Wang et al., 2000; Debandi et al., 2002), except in the former
Krameriaceae, which has elaiophores secreting lipids (Simpson, 1982). Data
available on
Huaceae
indicate absence of nectaries, if “disc” is assumed to
be a synonym for a receptacular nectary (Simmons & Hedin, 1999).
Celastrales.
There is a conspicuous annular receptacular nectary (intra- or
extrastaminal) in most families in this order. Particularly in
Celastraceae
,
the nectary is mostly intrastaminal, extending between the androecium and
