Pollen-Limited Fruit Set in Isolated Patches of Maianthemum canadense Desf. in New Jersey

Wade B. Worthen; Edmund W. Stiles

doi:10.2307/2996163

The reproductive biology of boreal forest herbs. II. Phenology of flowering and fruiting

Canadian Journal of Botany ◽

10.1139/b87-279 ◽

1987 ◽

Vol 65 (10) ◽

pp. 2047-2056 ◽

Cited By ~ 22

Author(s):

Kaius Helenurm ◽

Spencer C. H. Barrett

Keyword(s):

Boreal Forest ◽

Fruit Set ◽

Pollen Limitation ◽

Fruit Production ◽

Fruit Removal ◽

Cornus Canadensis ◽

Forest Herbs ◽

Pollinator Service ◽

Maianthemum Canadense ◽

Major Factors

The flowering and fruiting phenologies of 12 boreal forest herbs were recorded during 1979 (flowering and fruiting) and 1980 (flowering only) in spruce–fir forests of central New Brunswick. The species studied were Aralia nudicaulis, Chimaphila umbellata, Clintonia borealis, Cornus canadensis, Cypripedium acaule, Linnaea borealis, Maianthemum canadense, Medeola virginiana, Oxalis montana, Pyrola secunda, Trientalis borealis, and Trillium undulatum. Flowering in the community occurred from mid-May to the end of July. The order of flowering was maintained in the 2 years, but the degree of synchronization of inflorescences differed in several species. Fruiting in the community began in mid-July and extended beyond the end of September. The percentage of buds that ultimately bore fruit ranged from 0 (Cypripedium acaule) to 61% (Aralia nudicaulis). With the exception of Cypripedium acaule, which received little pollinator service, the self-incompatible species, Cornus canadensis, Maianthemum canadense, and Medeola virginiana, experienced the lowest levels of fruit-set. Pollen limitation and predation of developing fruit appear to be the major factors limiting percentage fruit-set in boreal forest herbs. Fruit production varied with time of flowering of inflorescences in several species, with periods of low fruit-set tending to coincide with lower densities of flowering inflorescences. Significant rates of fruit removal by herbivores occurred in all sarocochorous species. Disappearance of fruits from infructescences ranged from 31 (Medeola virginiana) to 95% (Aralia nudicaulis), with highest removal rates occurring during periods of greatest fruit availability.

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EFFECTS OF A SPLIT APPLICATION OF SEVIN-4-OIL® ON POLLINATORS AND FRUIT SET IN A SPRUCE–FIR FOREST

The Canadian Entomologist ◽

10.4039/ent116457-3 ◽

1984 ◽

Vol 116 (3) ◽

pp. 457-464

Author(s):

Richard W. Hansen ◽

Eben A. Osgood

Keyword(s):

Fruit Set ◽

Spruce Budworm ◽

Split Application ◽

Cornus Canadensis ◽

Native Bee ◽

Maianthemum Canadense ◽

Pollinator Populations

AbstractCounts of four pollinating insect groups were taken in unsprayed forest localities and in areas sprayed with a split application of Sevin-4-oil® (carbaryl) for spruce budworm control. Results indicate a reduction of pollinator populations due to spraying.Fruit set, measured by fecundity ratios (fruits/flower), was determined for Cornus canadensis L., Maianthemum canadense Desf., Clintonia borealis (Ait.) Raf., and Viburnum cassinoides L. in sprayed and unsprayed areas. Fecundity values for C. canadensis and M. canadense were significantly lower in sprayed than in unsprayed areas. Fruit set of C. borealis was apparently unaffected by carbaryl spraying, but the seed/flower ratio was significantly reduced in the sprayed area. V. cassinoides fecundity values were unaffected by carbaryl application. Reductions in native bee populations probably had the greatest impact on fruit set.

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Phenotypic and Demographic Variability Among Patches of Maianthemum canadense (Desf.) in Central New Jersey, and the use of Self-Incompatibility for Clone Discrimination

Bulletin of the Torrey Botanical Club ◽

10.2307/2996432 ◽

1986 ◽

Vol 113 (4) ◽

pp. 398 ◽

Cited By ~ 12

Author(s):

Wade B. Worthen ◽

Edmund W. Stiles

Keyword(s):

New Jersey ◽

Self Incompatibility ◽

Use Of Self ◽

Maianthemum Canadense

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The reproductive biology of boreal forest herbs. I. Breeding systems and pollination

Canadian Journal of Botany ◽

10.1139/b87-278 ◽

1987 ◽

Vol 65 (10) ◽

pp. 2036-2046 ◽

Cited By ~ 77

Author(s):

Spencer C. H. Barrett ◽

Kaius Helenurm

Keyword(s):

Boreal Forest ◽

Reproductive Biology ◽

Fruit Set ◽

Experimental Studies ◽

Reproductive Mode ◽

Breeding Systems ◽

Cornus Canadensis ◽

Forest Herbs ◽

Maianthemum Canadense ◽

Floral Syndromes

Detailed observations and experimental studies of the reproductive biology of 12 boreal forest herbs were conducted over a 3-year period (1978–1980) in spruce–fir forests of central New Brunswick. The species examined were Aralia nudicaulis, Chimaphila umbellata, Clintonia borealis, Cornus canadensis, Cypripedium acaule, Linnaea borealis, Maianthemum canadense, Medeola virginiana, Oxalis montana, Pyrola secunda, Trientalis borealis, and Trillium undulatum. All taxa are insectpollinated perennials and most exhibit clonal growth. Floral syndromes of the understory community are relatively unspecialized with many species possessing small white or green flowers. A total of 103 taxa of insects were collected from flowers during the 1979 season. Bombus spp. are the major pollinators of 5 of the 12 species. Syrphid flies, bee flies, and halictid and andrenid bees were also commonly observed. Controlled pollinations were undertaken to determine the breeding systems of herbs. Bagged, self-, cross- and open-pollinated treatments were used to investigate the capacity for self-pollination, compatibility status, and factors influencing fecundity in each species. A diversity of reproductive systems was revealed. Six species are completely dependent on insects for pollination, four species are weakly autogamous, one is strongly autogamous, and one appears to be apomictic. Comparisons of fruit-set and seed set from controlled self- and cross-pollinations indicate that four species are strongly self-compatible, one is dioecious, and the remainder display varying degrees of self-incompatibility. Despite this variation, outbreeding appears to be the most common reproductive mode. In several species there is evidence that low pollinator service limits fruit-set.

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