Biology Reference
In-Depth Information
Arecales.
The only family in this order,
Arecaceae
, presents three main in-
sect-pollination systems, with beetles, flies, and bees as pollinators
(Henderson, 1986). Septal nectaries are found in many palms, but their pres-
ence is variable even in closely related groups of species (Daumann, 1970;
Uhl & Moore, 1971; Rudall et al., 2003b; Stauffer & Endress, 2003), a circum-
stance correlated with mellitophilous flowers (Henderson, 1986). According to
Smets et al. (2000), nectaries have probably been lost in the cantharophilous
palms.
Poales.
The families in this order are mostly devoid of nectaries, since they
are primarily wind- or beetle-pollinated (
Anarthriaceae
,
Centrolepidaceae
,
Cyperaceae
,
Ecdeiocoleaceae
,
Flagellariaceae
,
Hydatellaceae
,
Joinvil-
leaceae
,
Juncaceae
,
Mayacaceae
,
Rapateaceae
,
Restionaceae
,
Sparga-
niaceae
,
Thurniaceae
,
Typhaceae
, and
Xyridaceae
). In exceptional cases,
some nectaries do occur, as in the floral bracts of some
Poaceae
(e.g.,
Nicora, 1941; Zuloaga & Sendulsky, 1988). Two families stand out in this
regard:
Bromeliaceae
, in which septal nectaries are widely distributed
(Daumann, 1970; Böhme, 1988; Bernardello et al., 1991; Sajo et al., 2004), and
Eriocaulaceae
, in which gynoecial glands (in pistillodes or style appendi-
ces) have been reported (Stützel & Gansser, 1995; Stützel, 1998; Smets
et al., 2000; Ramos et al., 2005).
Commelinales.
In this order,
Haemodoraceae
(Daumann, 1970; Simpson,
1990, 1993, 1998),
Hanguanaceae
(Rudall et al., 1999), and
Pontederia-
ceae
(Daumann, 1970; Strange et al., 2004) have septal nectaries. Only two
families do not have nectaries:
Commelinaceae
, with entomophilous pollen
flowers (Hrycan & Davis, 2005), and
Philydraceae
, with nectarless and
scentless pollen flowers (Hamann, 1998).
Zingiberales.
Most families possess septal nectaries:
Cannaceae
(Daumann,
1970),
Heliconiaceae
(Kirchoff, 1992),
Lowiaceae
(Larsen, 1998; Wen &
Liao, 1999),
Marantaceae
(Daumann, 1970; Rao, 1975),
Musaceae
(Daumann, 1970; Fahn & Benouaiche, 1979; Kirchoff, 1992), and
Stre-
litziaceae
(Daumann, 1970; Kronestedt & Walles, 1986). In
Costaceae
(Newman & Kirchoff, 1992) and
Zingiberaceae
(Rao, 1963; Box & Rudall,
2006), septal nectaries are absent; instead, these plants exhibit two, or rarely
three, conical epigynous glands, which are closely related in both families.
These nectaries have been interpreted as androecial or gynoecial in origin
(cf. Rao, 1963), as supragynopleural (Smets & Cresens, 1988; Newman &
Kirchoff, 1992; Smets et al., 2000), or as bipartite septal nectaries (Vogel,
1998b).
