Bernhardt & Weston, The pollination ecology of Persoonia 
785 
stronger or different upon bottling for less than 30 minutes. The scent is reminiscent 
of vanilla extract with undertones of commercial musk colognes. The floral odour of 
these two species is surprisingly similar to many of the neotropical, day-flowering 
orchids in the genus Encyclia (e.g. E. cordigera). 
The floral-yeasty scent of P. mollis and P. pinifolia is far weaker to the human nose 
when sampled in situ, producing a faint but pleasantly honey-like perfume 
reminiscent of Boronia, Plumeria or Narcissus flowers. Once bottled, these sweet floral 
odours become more pronounced within 30 minutes, but a yeast-like undertone can 
also be discerned. Persoonia glaucescens and P. isophylla also produce these weak 
scents but after bottling they seem closer to the vanilla-musk scent described above. 
The fruity scent of P. lanceolata and P. oxycoccoides is also weak to the human nose 
when sampled in situ. Upon bottling the concentrated odour is similar to ripe, 
commercial bananas or cherries. 
The 'green' smell of P. katerae and P. cornifolia is not discernible in situ and only 
becomes apparent 20-30 minutes after bottling. At that time the concentrated odour 
is reminiscent of freshly chopped, green beans or unripe tomatoes. 
If flowers of all the above species are bottled for 60 minutes or more, their original 
odour degrades into the green smell. 
Nectar 
Field examinations and lab dissections showed that nectar droplets are secreted by 
each of the four receptacular nectaries surrounding the gynoecium and flanking each 
of the four tepals (Fig. 1). Nectar droplets cling to the large nectaries or adhere to the 
smooth bases of the inner surfaces of the tepals when secretions are particularly copious. 
Nectar is usually retained in a restricted chamber formed by the base of the perianth, 
floral receptacle and ovary stalk. Access to the chamber is blocked by the ovary, which 
forms a roof, and by the degree of constriction of the tepals and anther bases (Fig. 1). 
Flowering branches bagged overnight contained nectar the following morning. Less 
than one microlitre of nectar could be removed from each individual flower of any 
species at any time, with the exception of P. silvatica and P. subvelutina. Bagged overnight, 
individual flowers of these two species produced a maximum of five microlitres of 
nectar. The sugar analyses of the nectar of P. subvelutina was 93.1% sucrose, 3.8% 
glucose and 3.1% fructose. P. pinifolia was 97.9% sucrose, 1.2% glucose and 0.9% fructose. 
Table 4. Scent descriptions of Persoonia spp. and results of Neutral Red tests. 
TAXON 
scent type 
Stig 
nect 
ant 
tep 
tepm 
trc 
cornifolia 
green smell 
++ 
++ 
++ 
+ 
+ 
++ 
isophylla 
sweet-yeasty 
+ 
++ 
++ 
+ 
+ 
+- 
katerae 
green smell 
+ 
++ 
+ 
+- 
+- 
+ 
levis 
green smell 
++ 
++ 
++ 
+ 
. ++ 
++ 
mollis subsp. ledifolia 
sweet-yeasty 
++ 
++ 
++ 
- 
+ 
++ 
mollis subsp, nectens 
sweet-yeasty 
+ 
++ 
++ 
+- 
+- 
+ 
oxycoccoides 
fruity 
++ 
++ 
++ 
+ 
++ 
NA 
pinifolia 
sweet-yeasty 
++ 
++ 
+ 
+- 
+~ 
++ 
* stig = stigma; nect = 
nectary; ant = anther; tep = 
glabrous 
inner surface of the tepal; tepm 
= tepal 
margins; trc = trichomes on the outer surface of the tepal and along the tepal margins; NA = not 
applicable — the flowers of this species are glabrous. 
