Fibre hemp is mainly a dioecious plant, although occasionally monoecious plants
are also found .
The species has mainly monoecious plants
but also genotypes with dioecious plants are found, a non-typical behavior in some disturbed areas.
Migalj (1969) found that the acetolyzed pollen grains of dioecious strains tended to have a diameter averaging about 33 pm, while the grains of monoecious strains were smaller, with a diameter averaging about 27 pm; and the pollen of dioecious plants was also more uniform, while that of monoecious plants
were more variable in size and in number of pores.
In relation to sexual systems, a greater frequency (82.6%) of hermaphroditic species, followed by monoecious plants
(8.7%), dioecious (6.5%), and andromonoecious (2.1 %) (represented only by one single species) (Table 1).
* Monoecious plants
have separate male and female flowers on the same plant.
The monoecious plants
have a propensity to self-fertilize due to the proximity of the male flowers to the female flowers (Franssen et al., 2001).
Among monoecious plants
, the classification of the plant that supplied the pollen is written first, followed by the classification of the plant that supplied the ovule and developed the seed.
Influence of environment on the floral sex ratio of monoecious plants
. Evolution 35:194-197.
And, is there a trade-off between male and female sex function in monoecious plants
? Second, to consider ecological specialization, I ask: Does dioecy show a selective advantage over monoecy under some environmental conditions?
Effects of pollen vector and plant geometry on floral sex ratio in monoecious plants
. American Midland Naturalist 130: 9.
usually need vectors in order to transfer pollen from staminate to pistillate flowers, on the same individual or between individuals.
Cross-pollination may be promoted by different mechanisms including: (1) pollen and stigma that mature at different times; (2) self-sterility or incompatibility, meaning that pollen from a flower cannot physiologically fertilize an ovule from the same plant even if the pollen does come into contact with the stigma; (3) dioecious plants where the male and female flowers are on separate plants; and (4) monoecious plants
that have imperfect flowers where the male and female reproductive parts are not contained within the same flower.