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Reproductive Biology and Uniform Culture of Portulaca in Hawaii
|Title:||Reproductive Biology and Uniform Culture of Portulaca in Hawaii|
Carr, Gerald D.
|Issue Date:||Apr 1990|
|Publisher:||University of Hawaii Press|
|Citation:||Kim I, Carr GD. 1990. Reproductive biology and uniform culture of Portulaca in Hawaii. Pac Sci 44(2): 123-129.|
|Abstract:||Ten taxa of Portulaca that occur in Hawaii (P. lutea, P.
molokiniensis, P. oleracea, P. pi/osa, P. sclerocarpa, P. villosa, two imperfectly
known species, and two cultivars) were included in a study of reproductive
biology and uniform cultivation. The response of plants under uniform conditions
upholds the merger of the reputed Hawaiian endemic P. cyanosperma with
P. pilosa. All Portulaca taxa in Hawaii are autogamous, and in most instances
large numbers of seeds are set even when the flowers are totally undisturbed.
Some taxa are facultatively cleistogamous, but even in chasmogamous forms the
flowers are open for only about 3-9 hr. The cultivars were the only taxa observed
to attract pollinators, but P. molokiniensis, which was not studied in nature, appears
to have adaptations for biotic pollination. Most of the portulac as studied
have capsular fruit that require about 13-17 days to mature, but in P. sclerocarpa
the fruits are thick-walled and indehiscent and require about 28 days for maturation.
The life cycle ranges from about 8 weeks in most cases to several months in
P. molokiniensis. However, individuals of most taxa typically flower and fruit
man y times during one growing season. Seeds were generally nondormant, but
partial seed dormancy was encountered in P. molokiniensis.
|Appears in Collections:||Pacific Science Volume 44, Number 2, 1990|
Carr, Gerald D.
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