Narcissus and Daffodil

1 The biology of Narcissus
Gordon R. Hanks
INTRODUCTION
The genus Narcissus L. belongs to the Monocotyledon family Amaryllidaceae, to
which it contributes some 80 species to its total of about 850 species in 60 genera
(Meerow and Snijman, 1998). The taxonomy of Narcissus is difficult because of the
ease with which hybridisation occurs naturally, accompanied by extensive cultivation,
breeding, selection, escape and naturalisation (Webb, 1980; see Chapter 3,
this volume). The genus is distinguished from other Amaryllids by the presence of
a perigonal corona structure (‘paraperigone’) forming a ring (‘cup’) or tube
(‘trumpet’) (Dahlgren et al., 1985). Unlike other genera of the family, Narcissus has
a mainly Mediterranean distribution, with a centre of diversity in the Iberian
Peninsula, and the genus also occurs in south-western France, northern Africa and
eastwards to Greece, while Narcissus tazetta is found not only in Spain and North
Africa but in a narrow band to China and Japan (Grey-Wilson and Mathew, 1981).
The eastwards distribution of N. tazetta may represent transfer along an ancient
trade route, illustrating the long human interest in the genus as an ornamental
plant, leading to its importance in commercial horticulture today (see Chapter 4,
this volume).
The survival of a number of Narcissus species has been threatened by past overcollection
and habitat destruction, not only in Spain and Portugal but also in
Morocco, Turkey and Belgium (Oldfield, 1989; Koopowitz and Kaye, 1990). The
‘Red List’ currently gives three Narcissus as ‘endangered’, five as ‘vulnerable’ and
six as ‘rare’ (WCMC, 1999). In the light of the environmentalist concerns in the
1990’s, the collection of wild bulbs has been addressed by the industry. However,
there is a need to maintain vigilance in the conservation of wild species and of their
many variants, to establish genetic collections for future breeding programmes,
and to develop sustainable production systems for their utilisation in commercial
horticulture.
Hybridisation has resulted in commercial narcissus cultivars that are in most
cases larger and more robust than their wild parents. Trumpet cultivars with
coloured perianth and corona originated from N. pseudonarcissus and its varieties,
and trumpet cultivars with white perianth and coloured corona from N. pseudonarcissus
ssp. bicolor. Large-cupped cultivars were the result of crosses between
N. pseudonarcissus and N. poeticus, back-crossed with N. poeticus to yield the smallcupped
cultivars. Multiheaded cultivars (the ‘Poetaz’ group) comprise mainly
hybrids of N. poeticus and N. tazetta (Doorenbos, 1954).