INTRODUCTION - Nectaries and Nectar - page 1

Chapter 1

INTRODUCTION

ETTORE PACINI 1 and SUSAN W. NICOLSON 2
1 Department of Environmental Sciences, University of Siena, Via Mattioli 4, 53100 Siena, Italy
2 Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa

1 EVOLUTIONARY ORIGINS

The evolutionary origins of nectaries and nectar are relatively obscure, but
several researchers, working on a broad scale on the evolution of angiosperm
families, have provided overviews of nectary incidence, diversity, origin,
and function. Two contrasting examples below show how concepts regard-
ing the origin of nectaries and nectar have been modified in the light of new
information. Firstly, in his outline of the classification of the angiosperms,
Armen Takhtajan (1980) gives a simple, concise statement on the purpose
and origin of nectaries:
The original pollinators were most probably beetles …. The original at-
tractant in insect pollination was the pollen …. But the necessity for
pollen economy leads to a course of evolution in which the flower starts
producing a cheaper foodstuff, nectar, as its alternative. For the produc-
tion of nectar special structures are formed as nectaries. They originated
independently in the most diverse lines of angiosperm evolution and on a
most widely varying morphological basis. With the emergence of nectar-
ies the plant gets an opportunity for producing pollen in more limited
quantities and using it only for transport to other flowers.

Later, based on new data from paleobotany and molecular systematics,
Peter Endress (1994a) discusses recent concepts of the evolution of angio-
sperm flowers and states:

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