The Carnivorous Plant FAQ v. 11.5
- courtesy of -
The International Carnivorous Plant Society

Q: North American Drosera

Species of Canada & USA1
D. anglica2
D. brevifolia3
D. capillaris3
D. filiformis var. filiformis
D. filiformis var. tracyi
D. intermedia4
D. linearis
D. rotundifolia2
1All in Drosera sect. Drosera.
2Also grows in temperate Asia and Europe.
3Ranges south to South America.
4Ranges into Europe and South America.

A: Although the USA and Canada is not home to a particularly large number of Drosera species, so many FAQ readers are from this region (including your humble FAQ-writer) that it makes sense to use a separate FAQ page to comment on the plants in this range.

These are all rosetted species with leaves that have glandular blades that range from short to very long and threadlike. If you have a plant that is hard to identify by the leaves, you will be happy to know that you can reliably identify them by seed shape and coat characters.

Cultivation is easy for most species. Grow them in a peat:sand mix, kept moist year-round, and in full sun. They are not picky about temperatures, but should not be exposed to frost during the growing season. I recommend you refer to weather data web sites (such as weather.com) and learn about the summer temperatures your plants would expect, based upon their native ranges. During the winter, all the species (except D. brevifolia and D. capillaris) produce winter resting buds to survive the chilly winter. These buds are called hibernacula. Hibernaculum-forming species should be given a dormancy as I describe in other FAQ pages; see the general cultivation guidelines and the relevant Dionaea pages. During the winter, do not expose your plants to temperatures below freezing unless you really know what you are doing, or are experimenting on spare plants.

Below I have some comments about each species. Range information is derived from Schlauer (1996) and Schnell (2002), supplemented by my own observations and searches of state heritage databases. I would appreciate hearing from regional biologists who might wish to correct my information!

Drosera anglica
Range (USA): Alaska, Washington, Oregon, California, Idaho, Montana, North Dakota, Minnesota, Wisconsin, Michigan, Maine, Hawaii.
Range (Canada): British Columbia, Alberta, Saskatchewan, Quebec, Newfoundland Island.

Drosera anglica is a beautiful plant with glandular leaf blades that are much longer than they are wide. The leaf blades of some plants are just a few times longer than they are wide, but the leaves of some strains are really long. Plants I have seen in parts of California, and herbarium sheets I have seen from Thunder Bay (Canada) are really long, so much so that the plants almost look like D. capensis! Drosera anglica is notable for occurring in Alaka'i Swamp, on Hawai'i.

Although fertile, Drosera anglica is thought to be of hybrid origin, that is D. rotundifolia×linearis. Sterile plants, referred to as D.×anglica, are found along with D. anglica where the two parent plants are found together.

Drosera brevifolia
Range (USA): Arkansas, southeastern Kansaseastern Texas, Louisiana, Mississippi, Alabama, Florida, Georgia, Tennessee, South Carolina, North Carolina, Virginia. Possibly Oklahoma, and Kentucky?

This is a cute litte plant that can be identified by its wedge-shaped leaves. Another way to identify it in the field is by the the flower scape, which is densely glandular. Two separate species have been described within this species, D. annua for the pink-flowered form found in the Gulf Coast and inland sites, and D. leucantha for the plant found along the Atlantic Coast. Subsequent studies have in general thrown these separate species into sullen disrepute, although you occasionally see the names pop up here and there. Just cross them out, and write "D. brevifolia" in its place.

Drosera capillaris
Range (USA): Texas, Louisiana, Mississippi, Alabama, Florida, Georgia, South Carolina, North Carolina, Virginia. Possibly Tennessee?

This is the typical sundew you are likely to encounter in the southeastern USA. Most of them are pink-flowered, but the occasional white-flowered plant is reported. Jim Fowler tells me that in the Green Swamp, in North Carolina, the typical flower color is white.

Those who have spent any time looking at D. capillaris in the Gulf Coast or peninsular Florida know that there are great populations of plants with leaves that are much larger than they should be, with thick and zesty petioles. These are referred to as "long-leafed" D. capillaris. What is going on with these plants? A cryptic species? A hybrid swarm with other plants? I do not know!

Drosera filiformis var. filiformis
Range (USA): Florida(?), North Carolina, Delaware, New York, New Jersey, Connecticut, Rhode Island, Massachusetts. Anecdotally reported for South Carolina.
Range (Canada): Nova Scotia.

Drosera filiformis is instantly recognizable. Its long, glistening leaves unfurling like fern-fronds are absolutely beautiful, especially when backlit at sunrise or sunset.

The species has been split into two varieties. The northern variety, D. filiformis var. filiformis, is smaller and more deeply red pigmented. Strangely, in the Florida panhandle, there are about five karst ponds with populations of plants which appear to be D. filiformis var. filiformis, but far out of its normal range. What's up with that? I have seen two of the populations, and do not think that they are introduced. They are very interesting critters. I describe some observations of these in more detail in a trip report for your interest.

Drosera filiformis var. tracyi
Range (USA): Mississippi, Alabama, Florida, Georgia.

This name is used to describe the southern variety of D. filiformis, which is larger, and with much paler leaves. Seeing a field of these plants glistening in the humid mist of an Alabama sunrise, backlit and glowing, is a delight you must treat yourself to while such things can still be viewed. The name Drosera tracyi for this variety has not been established, and so should not be used.

A completely anthocyanin-free form has been discovered. While it looks very much like a regular plant when vegetative, when it flowers you see immediately the white flowers that distinguishes it. Another entity that is worth cultivating is the hybrid between Drosera filiformis var. tracyi and Drosera filiformis var. filiformis. This plant is about as large as D. filiformis var. tracyi but is slightly more richly colored reddish. It was created by Joe Mazrimas, and goes by both D. × californica or Drosera 'California Sunset.'

Drosera intermedia
Range (USA): Minnesota, Wisconsin, Michigan, Illinois, Indiana, Ohio, Texas, Louisiana, Mississippi, Alabama, Florida, Georgia, Tennessee, South Carolina, North Carolina, Virginia, Maryland, Delaware, New Jersey, Pennsylvania, New York, and all of New England.
Range (Canada): Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island, Newfoundland Island.

This species has long narrow pedicels that point in the air at all angles, making a sort of hemisphere of death. This basic form is useful to keep in mind when trying to identify plants in the field. (Stipule form is also helpful in separating this from D. capillaris.) Another useful character is how the inflorescence does not emerge straight up from the center of the rosette---instead it emerges hortizontally, then arcs upwards.

This plant has a wide geographic range, so it should be no surprise that it has many variant forms. In some regions, D. intermedia is a ground-hugging rosette that looks very similar to D. capillaris. Other areas the petioles are exceedlingly long. I think that one of the most interesting forms is the kind easily observed in the New Jersey Pine Barrens. These plants have elongated stems, and the plants have a scrambling habit very similar to D. madagascariensis. Interesting.

Drosera linearis
Range (USA): Montana, Minnesota, Wisconsin, Michigan, Maine.
Range (Canada): Alberta, Ontario, Quebec, New Brunswick, Newfoundland Island.

This plant is an interesting critter I have only seen once in the wild, in Montana while the plants were in the dormant state. It is quite difficult to grow. (It tends to die during dormancy.) I have been growing plants for a few years, and it is very slow. In the Great Lakes area, it often grows in marl sites.

Drosera rotundifolia
Range (USA): Alaska, Washington, Oregon, California, Idaho, Montana, North Dakota, Minnesota, Wisconsin, Michigan, Illinois, Indiana, Ohio, West Virginia, Virginia, North Carolina, South Carolina, and states northeast to Maine. Possibly Georgia?
Range (Canada): British Columbian, Alberta, Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island, Newfoundland and Labrador.

This is a hugely widespread species, and is the one that Darwin performed all his experiments upon (some of which were almost unspeakably odd, I note). Its leaf blades are round, or even wider than long. It has the darling habit of closing its leaves over food bits.

Hybrids
I noted above that there is a hybrid between the two varieties of D. filiformis. But there are also a few naturally occurring hybrids between species (and of course, D. anglica is thought to be of hybrid origin). Very briefly, the recorded hybrids--all of which are sterile--are:

D.×obovata = D. rotundifolia×anglica
This plant has frequently been recorded wherever the parent plants both occur: Oregon, California, the Great Lakes province, New England, and southeastern Canada. This plant is intermediate in characters between the parents. Sometimes they can be very difficult to separate from Drosera anglica, especially when not in fruit. Typical leaf dimensions vary from site to site, mostly because of the Drosera anglica parent involved in the cross--D.×obovata that descended from long-leaved Drosera anglica may have leaves longer than short-leaved Drosera anglica! A horticulturally developed version has the peculiarly eroto-punitive name of "Ivan's Paddle."

Interestingly, if you accept that Drosera anglica is a plant of hybrid origin, then D.×obovata would merely be considered (by botanical nomenclature) to be a back-cross, and in such a case:
D.×obovata = Drosera anglica = D.×anglica.

D.×hybrida = D. filiformis×intermedia
This plant has only ever been observed in New Jersey as a native, although I have seen planted specimens growing in California. It it intermediate between the two species; long leaves with blunt tips. Easy to cultivate, it has been called a "poor man's Drosera linearis", because of its vague similarity to that species.

D. anglica×linearis
Reported by Schnell in Michigan, I presume it could be very difficult to identify, although if it is a vigorous plant it might be identifiable because of its lush growth habits.

D. capillaris×intermedia
Reported by Sheridan in 1987 in North Carolina, I don't know if anyone has ever followed up on this plant to verify its hybrid nature. This plant could be related to the "long-leafed" D. capillaris.

Page citations: Rice, B.A. 2006a; Schlauer, J. 1996, 2002; Schnell, D. 1976, 1999b, 2002a; Sheridan, P.M. 1987.

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Revised: May 2008
©Barry Rice, 2005