Biology Reference
In-Depth Information
Fig. 2.7
(
a
)
Dichromanthus michuacanus
, flower, front view; (
b
)
Deiregyne confusa
, flower, oblique
view, scale bars = 3 mm
Dichromanthus cinnabarinus
(Llave and Lexarza) Garay (=
S. cinnabarina
(LaLave and Lexarza) Hemsl.) (cinnabar ladies'-tresses) is found from southwest
Texas to Guatemala (Brown
1998
) and
D. michuacanus
(LaLave and Lexarza)
Salazar and Soto Arenas (=
Stenorrhynchos michuacanum
(LaLave and Lexarza)
Lindley or
Spiranthes michuacana
(LaLave and Lexarza) Hemsl.) (michoacan
ladies'-tresses) from southeastern Arizona and southwest Texas to Mexico (World
Checklist of Monocotyledons
2008
). Balogh and Greenwood (
1982
) originally sug-
gested without elaboration that
D. cinnabarinus
might be pollinated by bees.
However, the flowers are odorless and along with the entire spike are bright red to
yellow-orange, features which suggest hummingbird pollination (Luer
1975
; Brown
2002a
; Pridgeon et al.
2003
). According to Light (
1998
), the perianth is very hard
and may curb the efforts of nectar-robbing insects and birds to puncture the flower
base. Pollination rates are low. Coleman et al. (
2006
) found only three maturing
capsules in one population from Brewster County, Texas.
D. michuacanus
(Fig.
2.7a
), on the other hand, usually has white, cream-colored,
or pale green flowers with dark green stripes (nectar guides) and during the day
produces a strong lemony and faintly urine-like scent (e.g., Luer
1975
; Catling and
Brown
2002
). An exception is forma
armeniacus
R. A. Coleman, which has flowers
with a rich, apricot-yellow background color and a stronger, sweet odor (Coleman
2009
). Regardless of color, the plants are large with robust flowers and may be pol-
linated by bumblebees or carpenter bees. Coleman (
2005
) monitored four sites in
Arizona over a period of 9 years. He found that about 60% of plants initiating inflo-
rescences over this period failed to reach anthesis, mostly as a result of herbivory.
About 52% of plants that attempted to bloom in 1 year also attempted to bloom
again the following year. Relatively, few plants attempted to bloom more than 2
years in a row. Plants not flowering again a year after a blooming event were often
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