Biology Reference
In-Depth Information
Figure 5.
Gynoecial nectaries in a hypothetical flower. Nectaries on inferior ovaries:
at left
=
on the top of the ovary;
at right
= septal nectary and stylar nectary, from the base to the top of
the ovary, respectively (stylar nectaries can also be found in superior ovaries). Nectaries on
superior ovaries:
at left
= a nectariferous ring on the ovary base, glands on the ovary wall, and
stigmatic nectary, from the base to the ovary top, respectively;
at right
= septal nectaries.
Vogel, 1998c). In addition and as a consequence, homologies of discs in
cladistic analyses may be erroneous (Smets et al., 2000). Moreover, as there
is a broad range of potential ways to categorize receptacular nectaries, the
use of many subtypes is also discouraged, because it is not easy to devise a
classification that considers every potential position.
The exception may be the broad positional terms
intrastaminal
and
ex-
trastaminal
(Fig. 6), indicating nectaries borne on the receptacle between
the staminal whorl and the ovary, or between the perianth and the an-
droecium, respectively. Receptacular nectaries located exactly between the
stamens can be referred to as
interstaminal
. These words have been widely
used in this sense, being easy to understand and apply. Their systematic
value, however, must not be overemphasized. On the one hand, both types
can be found in the same plant group (e.g., Euphorbiaceae; Webster, 1994)
