Carnivorous Monocots: The Bromeliads

Most carnivorous plants are found within the vast diversity of dicotyledonous plants, those that begin life with two embryonic leaves emerging from their seeds. However, there are three species unique among carnivores in that they belong to the same clade as grasses, palm trees, pineapples, and irises; these are the carnivorous bromeliads. To mark the Database as now holding info files for all 3, this post is dedicated to these odd species.

Brocchinia reducta, the most commonly kept species

Bromeliads are an almost entirely New World group, found in North and South American tropical to subtropical regions (with the exception of one species found in western coastal Africa) and typically known for their development of pools of water between the wide, cupped leaf axils. Many species are grown for their tropical appearance and in some the bright flowers produced on sturdy stalks. Most bromeliads are epiphytes, growing on the trunks of trees and gathering water in their leaf axils and central urns to stay hydrated, but some species also live terrestrially in open land, even a few classified as succulents that survive in desert habitats.

Among the more than 50 genera and over 3,400 species however, only three have developed traits commonly considered to be carnivorous. The genus Brocchinia is genetically the most ancestral bromeliad group, with two terrestrial species having developed carnivorous attributes, and the genus Catopsis possesses one epiphytic species with similar traits. B. reducta is the most commonly grown species (and thus far, sadly, the only one that I can claim any experience with), it and its sister species B. hechtioides developing tightly bound rosettes of yellow-green leaves in the wild that form a central pool. Their leaves are covered in a powdery silver wax rendering grip by small organisms like insects difficult, sending them to the pool within, where at least B. reducta and possibly its sister have been recorded producing enzymes of their own to digest prey. C. berteroniana is similar in many ways, the Lampera de la selva ("Jungle Lantern") having yellowish leaves covered in silvery powder but capturing insects more in the axial pools between individual leaves than a single central pool. The Jungle Lantern however has not yet been recorded producing enzymes, instead currently believed to rely entirely on commensal organisms to digest captured prey that the plant can then absorb.

All 3 species are in cultivation, though the two Brocchinia are generally considered far easier to grow. In cultivation they tend to lose their unique tightly packed growth form and yellow color however, the often far dimmer lighting they experience giving rise to a shape more similar to most other bromeliads with broad green leaves spreading out in all directions. In my experience, B. reducta still retains the trait of a central urn, but small pools can begin forming between leaves as well. These bromeliads are all relatively large, exceeding 1-2 feet high and up to at least that diameter, and can live many years before deciding to flower, upon which they may set seeds or rely entirely on the production of pups around the plant base to propagate themselves. For any serious carnivorous plant grower, they are a unique if perhaps acquired taste to add to a collection, but a great way to introduce people unfamiliar to carnivores altogether to species that might resemble plants they have seen before in their local garden centers.