Listed below are some traits that
occur in the family and their occurrence in investigated genera. Bibliographic
references are listed in brackets [ ] after the characters. See
also Morphology and Anatomy.
and population biology:
habit, mycotrophy: Three tropical genera in the Gentianaceae are
completely without chlorophyll: Cotylanthera, Voyria, and
Voyriella. There are also reports of a mycotropic habit in one species
of Sebaea, Bartonia, and
Obolaria, but these three genera retain some chlorophyll in their
Buzz-pollination is known from Chironia
in South Africa; a plant that has anthers that only open at the top to let
the pollen out (similar to the buzz-pollinated anthers of Solanum,
the potato genus, in the family Solanaceae). Carpenter bees have visited
flowers of Coutoubea (A.
Popovkin, pers. obs.).
The North American bottle gentians (Gentiana
andrewsii and a few other species) have tubular, often closed
flowers, that are forced open and pollinated by bumblebees (Costelloe,
Bumblebees also visit more open Gentiana flowers, such as Gentiana
Frasera speciosa, the monument plant, is also pollinated by
bumblebees (of the genus Bombus) but has open flowers with easily
accessible nectaries (link)
Hummingbirds visit the flowers of
Symbolanthus pulcherrimus in Panama and
Macrocarpaea noctiluca in Ecuador [L.
Struwe, personal observation). Other gentians that probably at least
partly hummingbird pollinated includes Lagenanthus, Lehmanniella,
Lisianthius, Potalia, and Purdieanthus.
Moth-pollination has been recorded in
Macrocarpaea sodiroana in Ecuador [J-M Torres, personal
Chelonanthus alatus (earlier synonym Irlbachia alata) from the
Amazon Basin, South America, is pollinated by bats [Machado et al., 1998].
Possible bat-pollinated flowers occur also in
Macrocarpaea and Symbolanthus.
and nectaries: Ants visit the calyces of Fagraea racemosa (photo)
and the glandular base of the petioles of Anthocleista (photo). Tachia
has hollow stems and ants often lives inside the woody stems.
Animals and other organisms
that eat and attack gentians, see this page.
and seed dispersal:
Mammal-dispersal of fruits has been reported from Fagraea and Anthocleista.
In tropical Africa, Anthocleista trees are often visited by
hammerhead bats that feed on the fruits.
Some species of Fagraea are dispersed by birds.
Several species of Voyria has tiny
and long, thread-shpaed wind-dispersed seeds. In Gentiana
and Gentianella some species
have upright capsules on stiff stalks, that rattle in the wind - thereby
causing the seeds to shake out and disperse farther away than if they would
just fall down close to the mother plant.
A few Voyria species with round
seeds might use rainwater as dispersal agent.
Plant pathology and to find
out what eats gentians, see the pest page
S. 1969a. Chiropterophilie in der neotropischen Flora. Neue Mitteilungen
II, II. Spezieller Teil (Fortsetzung). Flora, Abt. B, 158: 185-222.
S. 1969b. Chiropterophilie in der neotropischen Flora. Neue Mitteilungen
III, II. Spezieller Teil (Fortsetzung). Flora, Abt. B, 158: 289-323.
= some species
© Lena Struwe, 2004-2011.