The carnivorous plant genera Byblis, Genlisea, Pinguicula, and Utricularia along with the murderous Ibicella and Proboscidea are in the plant order Lamiales (Wikipedia). Byblis is placed in its own family Byblidaceae. Genlisea, Pinguicula, and Utricularia are in their own family Lentibulariaceae. Ibicella and Proboscidea are placed in the family Martyniaceae consisting of 5 genera.

Close relatives of the Lamiales carnivores include the families Bignoniaceae (Trumpet Creeper, Jacaranda, Catalpa), Pedaliaceae (Sesame), Verbenaceae (Verbena, Lantana), Lamiaceae (Mint), and over a dozen others. We don't know which of these are sister clades to the carnivorous families because the divergence happened too long ago and too quickly to be resolved with current DNA testing. The fast evolving genes don't resolve divergences that old and the slowly evolving genes did not change enough during the short time period in which the Lamiales originally differentiated. A number of authors choose the Pedaliaceae (Wikipedia) as a sister of convenience to the Lentibulariaceae because the plants in that family tend to have sticky leaves.

There is not much to say about the evolution of Byblis at this point. In the DNA phylogenies it tends to fall in with families of plants that used to be considered part of the Scrophulariaceae and not close to the other carnivores. It has a unique design for its glands and appears to have evolved carnivory independently of the the other carnivores.

The Martyniaceae murderous plants are closer to the Lentibulariaceae carnivores but definitely not sisters. Comparing the glands of these plants it is also apparent they are not directly related.

DNA testing of the Lentibulariaceae carnivores provides an interesting history of the group.

DNA cladogram of the Lentibulariaceae carnivores (in black) with a non-carnivorous relative in green. The length of the lines horizontally are NOT proportional to genetic changes.

We have a flypaper carnivore basal in the clade and closely related to a pigeon trap carnivore and that is in turn related to a suction trap carnivore. This does NOT mean Pinguicula gave rise to Genlisea and Genlisea gave rise to Utricularia. What it says is at some point in the past Pinguicula and the Genlisea/Utricularia clade had a common ancestor. At a later time the Genlisea and Utricularia clade split. We can confirm this interpretation looking at the digestive glands of the three genera. Plachno, et al. (2005) has a summary of digestive gland fine-structural characters. There is a general Pinguicula to Genlisea to Utricularia trend. You can assign some characters to the common ancestor of the family Lentibulariaceae and some to the ancestor of the Genlisea/ Utricularia clade. However, other characters are only found in Genlisea or found in Pinguicula and more derived Genlisea but not primitive Genlisea.

Was the common ancestor of the Lentibulariaceae carnivorous? The Muller et al. papers listed below discuss the milestones in the evolution of the Lentibulariaceae carnivores. Since all three genera have superficially similar, vascularized digestive glands that also function to absorb nutrients it is likely the last common ancestor of the group was already a carnivore. It probably looked similar to Pinguicula lusitanica. That is it hugged the ground and the leaves rolled in but did not have as developed digestive or mucilage glands. After the split with the Genlisea/ Utricularia ancestor, the proto-Pinguicula further developed the digestive and mucilage glands. The ancestor that lead to Genlisea/ Utricularia probably formed pitcher-like leaves. Some Pinguicula species today will occasionally produce leaves that look like small horizontal pitchers. However those pitchers are peltate while the traps of Genlisea and Utricularia are rolled (see image of a Utricularia trap at right). The rolled leaves would have allowed the proto-Genlisea/ Utricularia to utilize a different resource if they were were buried or otherwise subsurface. The common ancestor may have had forked leaves since both genera have forked traps. In the Genlisea clade the trap elongated and the forks spiraled. In the Utricularia clade the trap shortened, folded back, and developed the sophisticated trap door mechanism at the leaf fork.

Jobson, et al. (2003) did a DNA study of 75 species of the Lentibulariaceae (there are more than 340 species in the family!) which was expanded for Pinguicula by Cieslack et al. (2005). Within the genus Pinguicula they found the non-hybernacula-forming warm temperate species to be basal (P. lusitanica and P. crystalina from Europe, P. antactica from southern South America, and the SE USA species). Most of the temperate Eurasian and North American hybernacula-forming Pinguicula fall into a single large clade of closely related species. The exceptions are the northeast Asian and Arctic P. ramosa, P. villosa, and P. varigata which form a clade and P. alpina. The Eurasian, hybernacula-forming P. alpina is basal to a clade consisting of the Mexican and Caribbean species. Forming a hybernacula or producing succulent, non-carnivorous leaves allows the Mexican and Caribbean species to survive in regions with distinct dry seasons.

However, P. alpina as we know it can not be the direct ancestor of the central American species. Besides the fact that P. alpina has a number of unique specializations not found in its relatives, it has the wrong number of chromosomes. Caspar and Stimper (2009) list chromosome numbers for 82 Pinguicula taxa. Most Mexican Pinguicula are diploids (x=11, 2n=22) while P. alpina is a tetrapoid with a different base number (x=8, 2n=32). The Pinguicula ancestral base number is x=8. Most of the non-Mexican Pinguicula are diploid, tetraploid, octoploid, and hexadecaploid x=8 (2n=16, 32, 64, 128) with a few interesting exceptions. Based on chromosome numbers in combination with the DNA data there are no clear candidates currently extant that appear to be directly ancestral to the Mexican species.

Cieslack et al. (2005) interpret the phylogeny to indicate Pinguicula originated in a humid subtropical environment and later developed specializations for surviving freezing or drying. Caspar and Stimper (2009) concur on this view based on the current locations of various chromosome variants. This is different from Jobson, et al. (2003) which placed the cold temperate species basal. Cieslack et al. (2005) tested more species giving them a better picture of the genus. Even with the extra species their analysis did not show strong confidence in the split between warm temperate and the cold temperate species. Even more testing may help here or Pinguicula invaded cold temperate or mountainous regions early on in which case the lack of confidence may reflect a close association. With the testing it may be difficult to trace any of these events if the key species in Europe were wiped out 14.8 million years ago as a result of the Nordlinger Ries impact [Wikipedia] and mid-miocene extinction event [Wikipedia].

Genlisea is found today in tropical South America, Africa, and Madagascar. At this point the DNA phylogenies are equivocal about the paleogeography of Genlisea. There appear to have been multiple exchanges between South America and Africa/ Madagascar.

Utricularia is found world-wide today but it appears the bulk of the diversification within the genus happened in South America although the most basal species are found in Australia. The main line of Utricularia species is terrestrial. Multiple times Utricularia invaded other habitats and continents. Besides bogs and fens it can be found on rock face seeps, stream sides, as an attached aquatic, and suspended aquatic. This diversity is reflected in the fact that 225 species have been described so far.

-- John Brittnacher

Utricularia Phylogeny

Pinguicula medusina hybernacula. The hybernacula allow the plant to survive the tropical dry season in southern Mexico.

Pinguicula pumila from the SE USA. These plants look like typical temperate Pinguicula.

Pinguicula ehlersiae grows in the mountains of east central Mexico at about 1500 m elevation. These are the typical wet season carnivorous leaves. The dry season leaves are succulent and not carnivorous.

Pinguicula lusitanica is found in Europe.

Pinguicula cyclosecta is found in the Mexican state of Nuevo León.

For a more detailed discussion please see the following articles and articles they reference.

Muller, K. and Th. Borsch and L. Legendre and I. Theisen and W. Barthlott (2002) Evolution of carnivory in the Lentibulariaceae: considerations based on molecular, morphological, and physiological evidence. Proc. 4th Intl. Carniv. Pl. Conf. pages 63-73 ( )

Muller K., T. Borsch, L. Legendre, S. Porembski, I. Theisen, and W. Barthlott (2004) Evolution of Carnivory in Lentibulariaceae and the Lamiales. Plant Biology 6(2004):477-490.

Muller, K., T. Borsch, L. Legendre, S. Porembski and W. Barthlott (2006) Recent Progress in Understanding the Evolution of Carnivorous Lentibulariaceae (Lamiales). Plant Biology 8(2006):748–757.

Muller, K. and T. Borsch (2005) Phylogenetics of Utricularia (Lentibulariaceae) and molecular evolution of the trnK intron in a lineage with high substitutional rates. Plant Syst. Evol. 250:39–67.

Jobson, R. W., J. Playford, K. M. Cameron, and V. A. Albert (2003) Molecular phylogenetics of Lentibulariaceae inferred from plastid rps16 intron and trnL-F DNA sequences: implications for character evolution and biogeography. Systematic Botany 28, 157 – 171.

Cieslack, T., J. S. Polepalli, A. White, K. Muller, T. Borsch, W. Barthlott, J. Steiger, A. Marchand, and L. Legendre (2005) Phylogenetic analysis of Pinguicula (Lentibulariaceae): chloroplast DNA sequences and morphology support several geographically distinct radiations. American Journal of Botany 92(10):1723–1736.

Plachno J. B., Kozieradska-Kiszkurno M., Swiatek P. (2007) Functional ultrastructure of Genlisea (Lentibulariaceae) digestive hairs. Ann. Bot. 100:195-203

Casper, S. Jost and Rosemarie Stimper (2009) Chromosome numbers in Pinguicula (Lentibulariaceae): survey, atlas, and taxonomic conclusions. Plant Syst. Evol. 277:21–60.

Previous page: Evolution -- the Caryophyllales Carnivores
Next page: Evolution -- the Ericales Carnivores