Tribe Calypsoeae - The Pollination Biology of North American Orchids: North of Florida and Mexico - page 122

higher fruit set (Snow and Whigham 1989 ). Since branching occurred in about half
the plants that exhibited natural levels of fruit production, development of a second
leaf was common and could potentially compensate for the negative effects of flow-
ering on leaf size (Whigham and O'Neill 1991 ). This, in combination with the com-
paratively low fruit set under natural conditions, might help to keep the costs of
reproduction in Tipularia to a minimum.
Corallorhiza Gagnebin (Coral Roots)
Corallorhiza is a genus of 11 mostly temperate North American species (Magrath
and Freudenstein 2002 ). One is circumboreal, and several extend as far south as
Honduras and Nicaragua (Freudenstein 1997 ). All lack laminate leaves and are
essentially mycoparasitic (Campbell 1970 ; Freudenstein 1994b ; Zimmer and
Gebauer 2008 ; Cameron et al. 2009 ). Seven species occur in North America north
of Mexico. Literature is available on the pollination of Corallorrhiza maculata
Rafinesque (spotted coral-root), Corallorhiza striata Lindley var. striata (striped
coral-root), Corallorhiza odontorhiza (Willdenow) Poiret var. odontorhiza and var.
pringlei (Greenman) Freudenstein (autumn coral-root), Corallorhiza bentleyi
Freudenstein (Bently's coral-root), and Corallorhiza trifida Chatelain (early or
northern coral-root).
Habitat and Distribution
C. maculata and C. striata var. striata are widely scattered across the USA and
southern Canada while C. odontorhiza is largely restricted to the eastern half of this
range. All three are often found in moist to dry deciduous, coniferous, or mixed
woods with C. striata var. striata also occurring in coniferous swamps and on lake-
shores. C. trifida is circumboreal and extends continuously across nearly all of
Canada and the northern states to New Mexico in the Cordillera. Northern popula-
tions occupy habitats similar to the above as well as tundra and muskeg, while
southern populations are usually found on stream banks or in cold, often coniferous,
swamps, wet deciduous woods, and bogs (Freudenstein 1997 ; Magrath and
Freudenstein 2002 ). C. bentleyi was originally found on an abandoned railroad
GRADEIN7EST6IRGINIABUTHASSINCEBEENLOCATEDATSEVERALADJACENTSOMEWHAT
DISTURBEDSITESINTHE!PPALACHIANMOUNTAINSOF6IRGINIAAND7EST6IRGINIA
(Freudenstein 1999 ; Horwitz 2006 ). Recent analysis based on plastid DNA and
morphological characters supports its recognition as a separate species and indi-
cates a close relationship with C. striata var. involuta (Greenm.) Freudenstein
(Barrett and Freudenstein 2009 ).