Tribes Cymbidieae and Epidendreae - The Pollination Biology of North American Orchids: North of Florida and Mexico - page 141

Fig. 7.1 Eulophia alta . ( a ) Flower, front view; ( b ) flower, side view, scale bars = 5 mm
Little pollination data are available for either species in North America.
Williamson ( 1984 ) reported autogamy in E. alta and a number of other Eulophia
species in Zambia, and autogamy has also been reported in populations of E. alta
FROM-EXICO3OUTH!FRICA&LORIDAAND0UERTO2ICO'OSS 1973 ; Catling 1990 ; van
der Cingle 2001 ). However, a recent study at a site in south Florida (Johnson et al.
2009 ) found spontaneous autogamy to be rare, with only 7.1% of the observed flow-
ers developing capsules. Moreover, autogamy produced seeds that developed more
slowly than seeds produced by other treatments. Hand pollinations significantly
increased capsule formation. Capsule set resulting from induced autogamy was
46.4%; geitonogamy, 64.3%; xenogamy with pollen from plants 10-100-m distant,
42.9%; xenogamy with pollen from plants greater than 10-km distant, 67.9%.
Johnson et al ( 2009 ) concluded that autogamy is uncommon in E. alta at their study
site and that the large numbers of capsules found in natural populations are probably
the product of unobserved cross-pollination events. Outcrossing is, in fact, a com-
mon mode of sexual reproduction elsewhere in the genus (e.g., Lock and Profita
1975 ; Singer and Cocucci 1997 ; Sun 1997 ; van der Cingle 2001 ; Peter and Johnson
2006 ; Jurgens et al. 2009 ).
Epidendreae
The Epidendreae includes 86 genera found in the Caribbean and North, Central, and
South America. Only two are present in North America north of Mexico and Florida
(Pridgeon et al. 2005 ).