Tribe Malaxideae - The Pollination Biology of North American Orchids: North of Florida and Mexico - page 95

Fig. 5.2 Fungus gnat with pollinia of Malaxis paludosa attached to the anterior ventral thorax,
scale bar = 0.3 mm. po pollinia
none carried pollinia. The smaller European version of M. paludosa is apparently
pollinated by tiny bog flies (Davies et al. 1988 ).
Fruiting Success and Limiting Factors
Even though pollen vectors were only rarely observed, both Darwin ( 1862 ) and
2EEVESAND2EEVES 1984 ) reported that pollinia were removed from most flowers.
2EEVESAND2EEVES 1984 ) found that 20.5% of the flowers in their study area pro-
duced fruit in 1983 with a mean of 3.64 fruits per plant and a maximum of 7. In
1984, this average dropped to 2.17. The modal number for the 2 years was 4 and this
number was produced by about 28% of the plants. In 1983, 64% of the plants pro-
duced 4-7 fruits compared to 22% in 1984 with the variation provisionally attributed
to differences in rainfall. Although the sample was very limited, Darwin ( 1862 )
reported an even higher level of natural fruit set with 13 of 21 flowers (62%) on one
spike producing capsules. The level of fruit production can therefore be substantial,
although seed viability and seedling recruitment remain to be examined. By way of
comparison, fruit set in a deceptive, obligately outcrossing, and reportedly pollinator
LIMITED0UERTO2ICANSPECIES M. massonii 2IDL+UNTZEWASONLY!RAGON
and Ackerman 2001 ).