There are two carnivorous plant families in the plant order Ericales [Wikipedia]. The family Roridulaceae contains only the two species of Roridula. The family Sarraceniaceae contains the genera Sarracenia, Heliamphora, and Darlingtonia. Their Ericales relatives include kiwifruit, blueberries, persimmon, heath, rhododendron, camellia, primrose and other familiar plants. Based on DNA testing, the closest family to the carnivorous Ericales is the Actinidiaceae [Wikipedia].

Darlingtonia is most basal genus of the Sarraceniaceae clade. It is found on the west coast of the USA at sea level on the coast and higher elevations inland, usually in toxic serpentine soils. Heliamphora is found in equatorial South America at high elevations where it is generally cold and foggy, usually on high plateaus. Sarracenia is found in the warm temperate region of the southeast USA except Sarracenia purpurea which is also found in the northeast and north central USA and Canada.

Knowing the closest famiy to the Ericales carnivores doesn't give us any hints about the evolution of carnivory in this group and maybe that is a hint in itself.  There are species in the family Actinidiaceae that have hairy leaves but most do not. And Roridula has little in common with the Sarraceniaceae carnivores so we have to assume it evolved carnivory independently. The Sarraceniaceae use folded leaves as traps while Roridula uses a glandular hair-based trapping mechanism. Roridula does not have glands that secrete digestive enzymes like the Sarraceniaceae, but it does have adaptations for efficient absorption of nutrients on its leaves, as does the Sarraceniaceae.

The Roridulaceae/Sarraceniaceae situation of sticky-leaved plants closely related to pitcher plants is similar to what we see with the Nepenthales carnivores. The Nepenthes pitcher plants are closely related to Drosophyllum and Triphyophyllum sticky-leaved plants. One posibility is pitcher plants evolved from sticky-leaved plants in high rainfall environments. However, in both cases there is no evidence of that in the phylogeny. That is, the pitcher plants are not embedded in the sticky-leaved plant lineages—they appear to have evolved in parallel.

There is another big clue in the evolution within the Ericales carnivores involving fossils. Sadowski et al. (2015) published a study on carnivorous plant leaves in 35–47 million years old Eocene Baltic amber. The leaves are virtually identical to modern Roridula leaves. The Ellison et al. (2012) paper places the split between Roridula and Actinidia at 38 million years ago with a statistical range of 32 to 45 million years ago. That places the fully carnivorous leaves of Roridula very early in the Roridula lineage and it places early Roridula in what is now northern Europe which is not exactly close to southern Africa where it is only found today.

There may be a similar story for the Sarraceniaceae lineage. Notice in the cladogram above that about 10 million years ago there was one lineage of Heliamphora that gave rise to all known Heliamphora species. There could have been dozens of Heliamphora species during the 15 million year gap before that but they have no known surviving successors. The same goes for Sarracenia where about 5 million years ago after an almost 20 million year gap, one surviving lineage gave rise to two surviving lineages. It was one to two million years before we see those lineages expanding into the current ranges for the various species. Without fossils or a complex lineage over a large range, we cannot really know where those plants were or why all but one species was lost or what other unique carnivores were lost. A likely scenario involves long distance dispersal but that is just one of many possibilities including continents moving creating climate change requiring plant species to shuffle around and rare events such a large meteor strike in eastern North America 35 million years ago [Wikipedia].

The Sarraceniaceae carnivores are all pitcher plants. The exact trapping mechanisms may vary among the species but they are all essentially traps constructed from a rolled leaf. It is easiest to see this in the Heliamphora leaves. Although it may look more primitive, Heliamphora isn't primitive. Its juvenile pitchers actually look like Sarracenia pitchers and the adult pitchers have features not found in other pitcher plants. The most notable feature is a hole or slit which limits the water level in the pitchers. The slit has hairs to keep prey from washing out.

The juvenile pitchers of Sarracenia, Heliamphora and Darlingtonia are reminiscent of each other and very similar to mature S. minor pitchers. The most likely explanation for the similar juvenile pitchers in the three genera is the small plants have similar prey such as springtails and there would be no selection pressure to be other than how they are. 

My personal observations about differences in Sarraceniaceae traps is Heliamphora does not pump water into its traps. The traps rely on rain to fill with water and excess water goes out a drain hole or slit. Sarracenia and Darlingtonia will pump water into their traps but only want a few cm of water in them. If fertilizer-water is put in the traps, Sarracenia pumps the water out the roots into the soil while Darlingtonia pumps the water out the sides of the traps. The genera had millions of years to develop these specific adaptations to their local environments.

The flowers of Darlingtonia and Sarracenia are highly modified in a way that decreases selfing. Both have one-way routes for the pollinator to follow. Darlingtonia is pollinated by a small bee that enters gaps between the petals (in a photo they look like wicked eyes) and exits (or falls) through the lower part of flower first encountering the stigmas and then the stamens. Sarracenia is pollinated primarily by bumblebees. Common bees such as honey bees, carpenter bees, and many bumblebee species do not know how or are not able to enter the flower. The knowing bumblebees push past the stigma to enter the cavity created by the expanded style hopefully leaving pollen behind on the stigma. They take all the pollen and exit under a petal. Flowers like this evolved via a kind of run-away-feedback selection: the more a species selects for outcrossing, the more genetic load it acquires, the more it needs to outcross to avoid inbreeding depression. The result is increased genetic variation within a population which facilitates faster evolutionary adaptation. The downside of this in the case of Darlingtonia and Sarracenia is if the pollinators go extinct there isn't a backup plan.

Heliamphora uses a more typical pollination scheme among flowering plants to increase genetic variation of having the stigma mature and lose receptivity before the anthers mature and release pollen. This isn't a detriment to long distance dispersal the way self-incompatibility is since a large plant could have a number of flowers in the appropriate stage to effectively self pollinate.

Neyland and Merchant (2006) did a DNA study of the Sarraceniaceae. They used a DNA marker that nicely showed the relationships of certain clades but could not clearly differentiate the majority of Sarracenia species.

From this you can see within Sarracenia, S. purpurea and S. rosea are clearly delineated from each other and quite delineated from the rest of Sarracenia. Neyland and Merchant (2006) argue there is no genetic support for splitting S. alabamensis and S. jonesii from S. rubra. I would argue there is no support for delineating any of the species beyond S. purpurea and S. rosea. The reasons are the species diversified too recently for there to be enough genetic assortment between the species in the genes used and there may still be too much gene sharing (introgression) between the species to be able to get statistically significant results. Whole genome studies would undoubably be interesting but may also confuse the taxonomy even more.

-- John Brittnacher  
January 2010  
Latest update February 2026

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

Anderson, Arne A., Rydin Catarina, and Mari Kallersjo (2002) Phylogenetic relationships in the order Ericales s.l.: Analyses of molecular data from five genes from the plastid and mitochondrial genomes. American Journal of Botany 89(4):677-787. https://doi.org/10.3732/ajb.89.4.677

Neyland, Ray and Mark Merchant (2006) Systematic relationships of Sarraceniaceae inferred from nuclear ribosomal DNA sequences. Madrono 53(3):223-232. https://doi.org/10.3120/0024-9637(2006)53[223:SROSIF]2.0.CO;2

Sheridan, Philip M. (1991) What is the identity of the west gulf coast pitcher plant, Sarracenia alata Wood? Carniv. Pl. Newslett. 20(4):102-110 https://doi.org/10.55360/cpn204.ps220 ( PDF )

Sheridan, Philip M. and David N. Karowe (2000) Inbreeding, outbreeding, and heterosis in the yellow pitcher plant, Sarracenia flava (Sarraceniaceae), in Virginia. American Journal of Botany 87:1628-1633 https://doi.org/10.2307/2656739

Ellison AM, Butler ED, Hicks EJ, Naczi RFC, Calie PJ, et al. (2012) Phylogeny and Biogeography of the Carnivorous Plant Family Sarraceniaceae. PLoS ONE 7(6):e39291. https://doi.org/10.1371/journal.pone.0039291

John Brittnacher (2013) Phylogeny and Biogeography of the Sarraceniaceae. Carniv. Pl. Newslett. 42(3):99-106 https://doi.org/10.55360/cpn423.jb578 ( PDF )

Löfstrand, Stefan and Schönenberger, Jürg (2015) Molecular phylogenetics and floral evolution in the sarracenioid clade (Actinidiaceae, Roridulaceae and Sarraceniaceae) of Ericales. Taxon 64:1209-1224. https://doi.org/10.12705/646.6

Sadowski E., L.J. Seyfullah, F. Sadowski, A. Fleischmann, H. Behling, and A.R. Schmidt (2015) Carnivorous leaves from Baltic amber. Proc. Natl. Acad. Sci. U.S.A. 112 (1) 190-195 https://doi.org/10.1073/pnas.1414777111

Sarracenia purpurea subsp. purpurea.

Sarracenia flava, Columbus Co., North Carolina, USA.

Roridula dentata from South Africa.

Roridula dentata flower.

Heliamphora nutans flower. H. nutans is found on Roraima, Kukenán, and Wei tepui near the Venezuela, Guyana, Brazil border.

Juvenile Heliamphora nutans showing the Sarracenia-like leaves.

Darlingtonia californica seedlng.

Darlingtonia californica flowers, Sierra Nevada, California, USA. The flowers have separate entrances and exits for its pollinator which decreases self-pollination.

Sarracenia rubra subsp. rubra flower. To get to the pollen and nectar inside the flower, bumblebees push past the stigmas on the tips of the umbrella shaped style. They exit under the petals. Having separate a separate entrance and exit, the flower isn't self pollinated. Of course the plant can have multiple flowers open at the same time and self pollinate that way.

Heliamphora heterodoxa x ionasi.

Darlingtonia californica, Del Norte Co., California, USA.

Sarracenia psittacina.