Leaf colour patterns, vegetative and sexual reproduction of Episcia ...

Figure 27 Episcia lilacina; left: flower in male stage; right: flower in female stage.
Discussion: Protandry – like in Episcia lilacina – is quite common in the family of
Gesneriaceae (Denham 2004). It poses an effective method to avoid self-pollination.
Observations of the longevity of individual flowers are scarce (Wiehler 1983). As noted by
Primack (1985), the length of time the anthesis lasts can influence its total number of pollinator
visits, which, in turn, can affect the amount and diversity of pollen a flower receives and the
amount of pollen it disseminates. A period of 4 days of anthesis is stated for the species of
Drymonia (Endress 1994). Primack (1985) indicates a longevity of averaged 1.3 days with a range
of 1-3 days for tropical rain forests. Due to the fact that Episcia lilacina’s flowers can be easily
damaged by environmental influences but even though feature a two to three days timeframe for
the anthesis the flowers can be considered durable above average.
Over 80% of the flower species tested by Primack (1985) showed a male stage much shorter
than the female one. Due to Primack this is caused by the fact that the usefulness of the male
flowers to the plant is over as soon as the pollen is shed and that may occur in many species
within hours after the flower has opened.
Because the male as well as later on the female stages begin in the early morning the
legitimate pollinator has to be day-active. Thus Noctuidae (moth) and Sphingidae (hawkmoth)
can be excluded due to their overly night-active nature (Endress 1994). As stated by Faegri and
Pijl (1979), the diurnal anthesis without closing at night favours butterflies (Rhopalocera) as
pollinators. Opler (1983) claims that most butterflies feed on nectar between 8.00 and 15.00,
beginning later and stopping earlier than other diurnal nectarivores. Other authors (Roubik 1989,
Armbruster and McCormick 1990) allege that the early morning is a major foraging time for bees.
Therefore, many bee flowers open at that time or earlier during the night. This statement
concerning psychophilous flowers is in contrast to Episcia lilacina because the opening of the bud
as well as the beginning of the female stage occurs early in the morning and still in the night,
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