The diverse Piper genus (Piperaceae) is used as a model system for a variety of ecological studies, including work done by Dyer at La Selva on tritrophic interactions (i.e., plant [Piper] – caterpillar – parasitoid). It’s also economically important – we grind the dried fruit or seed to produce pepper.
Here is a flower spike of a common species in Cahuita –I have no clue which – and a spider with stabilimentum that was often present with patches of Piper.
Croton argenteus confused me for a while. I had encountered the species in and around the Palo Verde wetland as a small, emergent plant, and had assumed it was annual or at least without above ground tissue across years because it was not present in the beginning of the season and it was flowering soon after emerging. As such, I could not find it in the keys….
Then, while driving to Reserva Biologica Lomas de Barbudal to help Ramsa (a PhD student studying watershed land-use effects on insect communities in and around dry-forest streams), I spotted a large shrub that looked surprisingly similar to my yet unidentified wetland plant. When I returned and picked up the shrub and tree book – bingo.
I suspect that cattle grazing knocks back this species from growing to a shrub-like state, since there is frequently evidence of herbivory on the small plants I encountered.
There are at least 4 species of Pontederiaceae in the Tempisque River basin. Here is one: Heteranthera limosa, a small, emergent plant inhabiting well lit, recently flooded, shallow areas of wetlands. The entire plant is relatively delicate, perhaps as a result of fast growth. Unfortunately, I didn’t catch any with flowers open – it may occur during a certain time of the day, because I did see this open earlier in the morning.
One of three Lemnaceae species in the Tempisque River basin.
Superficially similar to Thalia geniculata, Canna glauca is another common emergent wetland plant with broad leaves and a tall florescence stalk that thrives in shallow-water areas. The large yellow flowers are uniquely irregular, and the ball-like, floating fruits are also distinctive.
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This September, the Palo Verde wetland was clear enough to easily see to the bottom where there were no macrophytes present blocking the sunlight. This phenomenon is in sharp contrast to what is observed early in the wet season, when tannins and other darkening pigments are leached into the waters from copious amounts of decomposing organic matter and the wetland water appears almost black.
As a result, lily stems can be seen and traced to their origin.
