Sarracenia
Sarracenia | |
---|---|
Sarracenia species and hybrids | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Ericales |
Family: | Sarraceniaceae |
Genus: | Sarracenia L. |
Species | |
See text | |
Sarracenia range (all species) |
Sarracenia (
Sarracenia is a genus of
The plant attracts its insect
Description
Sarracenia are
The inside of the pitcher tube, depending on the species, can be divided into three to five distinguishable zones: zone 1 is the operculum (or hood), zone 2 is the peristome and rest of the trap entrance, while zones 3 and 4 (which in some species are combined) and 5 (only present in S. purpurea) are further divisions of the actual tube. Each of these zones has a specific function, with corresponding morphophysiological characteristics.
- Zone 1: Operculum. In most species the operculum covers at least part of the pitcher has an opening, preventing rain from excessively filling the pitcher, which would result in the loss of prey and dilute the digestive fluid. The operculum also serves to guide prey to the pitcher opening, using a combination of color, scent, and downward-pointing hairs to lead insects toward the trap entrance. Some species, specifically translucent "windows" which confuse prey into attempting to fly through the operculum, thereby causing them to cascade down the pitcher tube. (A similar, better-developed mechanism is found in the closely related Darlingtonia californica).
- Zone 2: Peristome and trap entrance. This zone is composed mainly of the peristome, which produces copious amounts of nectar, luring insect prey to land or crawl onto the perilous footing surrounding the pitcher trap. This zone also includes the waxy upper portion of the pitcher tube. Footing on this zone is especially treacherous, as the waxy deposits on surface of this zone cause unwary insects to lose their footing and tumble into the pitcher depths.
- Zone 3: Located below Zone 2, this zone features a leaf surface with non-existent footing, as well as a coating of ultra-fine, downward pointing hairs. Insects that have made it this far lose any chance of escape. It is also studded with digestive glands, which secrete digestive enzymes into the digestive fluid.
- Zone 4: This is the final zone in most species. It is filled with digestive fluids, and readily absorbs nutrients released from the insects by the work of the digestive enzymes and bacteria in the pitcher fluid. Along with more digestive glands, this zone features a thick coating of coarse downward pointing hairs, which makes escape from the digestive fluids impossible.
- Zone 5: This zone, located below Zone 4 and found only in S. purpurea, is smooth, glabrous, lacks glands, and does not serve as an absorptive zone. Its function is unknown.
Carnivorous mechanism
All Sarracenia trap insects and other prey without the use of moving parts. Their traps are static and are based on a combination of lures (including color, scent, and nectar) and inescapability – typically the entrances to the traps are one-way by virtue of the highly adapted features listed above.
Most species use a combination of scent, waxy deposits (to clog insect feet) and gravity to topple insect prey into their pitcher. Once inside, the insect finds the footing very slippery with a waxy surface covering the walls of the pitcher. Further down the tube, downward-pointing hairs make retreat impossible, and in the lowest region of the tube, a pool of liquid containing digestive enzymes and wetting agents quickly drowns the prey and begins digestion. The exoskeletons are usually not digested, and over the course of the summer fill up the pitcher tube.
Only S. purpurea normally contains significant amounts of rainwater in its tubular pitchers. It is a myth that all species contain water. In fact, the hoods of the other species help to keep out rain water in addition to keeping flying prey from escaping.
S. psittacina, the parrot pitcher, uses a lobster-pot style trap that will admit prey (including tadpoles and small fish during floods) but not allow it to find its way out; and sharp inward-pointing hairs force the victim gradually down to the base of the pitcher where it is digested.
Potential narcotic function of coniine
Coniine, a toxic alkaloid also present in poison hemlock, was first detected in the nectar of S. flava.[1] and has since been detected in 7 other species of Sarracenia.[2] While it was demonstrated that concentrated extracts from S. flava could paralyze ants,[1] it has not been demonstrated that coniine has narcotic effects on insects at the concentrations naturally present in pitchers of S. flava. Other authors hypothesize that coniine may function as an attractant for insects, or may function both as an attractant and a narcotic.[2]
Flowers and seeds
Flowers are produced early in spring, with or slightly ahead of the first pitchers. They are held singly on long stems, generally well above the pitcher traps to avoid the trapping of potential
Floral formula: Ca5 Co5 A∞ G(5)
The flowers of almost all species are scented. The
Flowers generally last about two weeks. At the end of the flowering period, the petals drop and the ovary, if pollinated, begins to swell. The seed forms in five lobes, with one lobe producing significantly smaller numbers of seeds than the other lobes.[3] On average, 300–600 seed are produced,[3] depending on species and pollination success. Seed takes five months to mature, at which point the seed pod turns brown and splits open, scattering seed. The seeds are 1.5–2 mm in length and have a rough, waxy coat which makes it hydrophobic, possibly for seed dispersal by flowing water.[4] Sarracenia seed requires a stratification period to germinate in large numbers. Plants grown from seed start producing functioning traps almost immediately, although they differ in morphology from adult traps for the first year or so, being simpler in structure. Plants require 3–5 years to reach maturity from seed.
Growth cycle
Pitcher production begins at the end of the flowering period in spring, and lasts until late autumn. At the end of autumn, the pitchers begin to wither and the plants produce non-carnivorous leaves called phyllodia, which play a role in the economics of carnivory in these species. Since the supply of insects during winter is decreased, and the onset of cold weather slows plant metabolism and other processes, putting energy into producing carnivorous leaves would be uneconomical for the plant.
Genetics
The genus has been found to have a
Range and habitat
Seven of the eight species are confined to the south-eastern coastal plain of the
Sarracenia tend to inhabit fens, herb bogs, and seasonally wet grasslands. These habitats tend to be acidic (low pH) with soil made up of sand and Sphagnum moss. Frequently, the soil will be poor in nutrients, particularly nitrates, and often continuously leached by moving water or made unavailable to the plant roots by the low pH. The plants gain their advantage from their ability to extract nutrients from insect prey in this mineral-poor environment. The plants prefer strong, direct sunlight with no shade. Sarracenia habitats in the southeastern Coastal Plain consist primarily of fire-maintained pine savannas, wet prairies, or seepage bogs. Without frequent fire (1–3 years), these habitats undergo ecological succession and are quickly invaded by woody shrubs and trees, which eliminate Sarracenia by increasing shade and reducing soil moisture.
In several cases, carnivorous plant enthusiasts have introduced S. purpurea into suitable habitats outside of its natural range, where it has naturalized. Some of these populations are decades old; the oldest known occurrence in the Swiss
Environmental status
Sarracenia are threatened in the wild by development and the drainage of their
Some protective
Some efforts have been made to curb the existing threats to plants. In 2003 the International Carnivorous Plant Society ran a trial distribution program in which young S. rubra subsp. alabamanensis plants were grown from seed collected from 3 of the 12 known S. alabamanensis sites, and were distributed to members in an attempt to increase availability of this plant in cultivation, with the hopes of thereby decreasing the poaching that was endangering the survival of this taxon in the wild.[11]
In 1995, the
In 2004, a number of concerned plant enthusiasts founded the
One of the biggest challenges of reintroducing plants back into the wild is the unintended introduction of unwanted species, such as pests, diseases, and invasive weeds. Often, it is human destruction of areas in which the Sarracenia thrive that is a major killer. Aside from determining what genetic material is appropriate for reintroduction (which is up for debate), plants must be semi-aseptic to keep the habitat pristine and sustainable in the long term. Another challenge is maintaining all of the introduced plant material and determining an optimal site to plant them in. A single hurricane or storm event can change the dynamics of a field. Even within a single bog, some areas may be waterlogged, while other areas may become very dry, so identifying the right location is critical. Short term results on private property indicate planting larger specimens into the field have a higher chance of long-term survival compared to planting smaller seedlings.
Taxonomy
The genus Sarracenia belongs to the family
Typically anywhere from 8 to 11 species of Sarracenia are generally recognized, depending on individual opinions on the biological species concept and which among many subspecies and varieties should be elevated to species status, a common lumping and splitting problem in demarcation.[14] Some authorities split the described subspecific taxa of S. rubra into 3 to 5 species. Similarly, S. rosea is not always recognized as a species distinct from S. purpurea. The most commonly recognized species include:
Species | Authority | Year | Image | Distribution |
---|---|---|---|---|
Sarracenia alabamensis | Case & R.B.Case | 2005 | Alabama, eastern Mississippi and Florida. | |
Sarracenia alata Pale pitcher plant | (Alph.Wood) Alph.Wood | 1863 | eastern Louisiana across southern Mississippi and into western Alabama and a western range from eastern Texas into western Louisiana. | |
Sarracenia flava Yellow pitcher plant | L. | 1753 | southern Alabama, through Florida and Georgia, southern Virginia, North Carolina and South Carolina. | |
Sarracenia jonesii | Wherry | 1929 | North Carolina and South Carolina. | |
Sarracenia leucophylla White pitcher plant | Raf. | 1817 | west of the Apalachicola River on the Florida Panhandle. It is also found in Alabama, Georgia, Louisiana, Mississippi, and North Carolina | |
Sarracenia minor Hooded pitcher plant | Walt. | 1803 | northern Florida and in Georgia up to the southern part of North Carolina. | |
Sarracenia oreophila Green pitcher plant | (Kearney) Wherry | 1933 | northern Alabama, North Carolina, Georgia, and—historically—Tennessee | |
Sarracenia psittacina Parrot pitcher plant | Michx. | 1803 | Louisiana, Alabama, Mississippi, Florida, Georgia | |
Sarracenia purpurea Purple pitcher plant | L. | 1753 | Eastern seaboard, the Great Lakes region , Canada (except Nunavut and Yukon), Washington state, and Alaska.
| |
Sarracenia rosea | Naczi, Case & R.B.Case | 1999 | Mississippi to Georgia. | |
Sarracenia rubra Sweet pitcher plant | Walt. | 1788 | southern Mississippi, through southern Alabama, the Florida panhandle and Georgia, to the coastal plains of Virginia and South Carolina. |
Currently, S. rubra can be described as having six subspecies, though it is sometimes argued that the subspecies should be elevated to species rank in recognition of the
McPherson & Schnell (2011)
Stewart McPherson and Donald Schnell carried out a comprehensive taxonomic revision of the genus in their 2011 monograph, Sarraceniaceae of North America. They recognized the following taxa:[16]
- Sarracenia alata
- S. alata var. alata (autonym)
- S. alata var. alata f. viridescens S.McPherson & D.E.Schnell[nb a]
- S. alata var. atrorubra S.McPherson & D.E.Schnell
- S. alata var. cuprea S.McPherson & D.E.Schnell
- S. alata var. nigropurpurea P.D'Amato ex S.McPherson & D.E.Schnell
- S. alata var. ornata S.McPherson & D.E.Schnell
- S. alata var. rubrioperculata S.McPherson & D.E.Schnell
- S. alata var. alata (autonym)
- Sarracenia flava
- S. flava var. flava (autonym)
- S. flava var. flava f. viridescens S.McPherson & D.E.Schnell[nb a]
- S. flava var. atropurpurea (Hort. W.Bull ex Mast.) Hort. W.Bull ex W.Robinson
- S. flava var. cuprea D.E.Schnell
- S. flava var. maxima Hort. W.Bull ex Mast.
- S. flava var. ornata Hort. Bull ex W.Robinson
- S. flava var. rubricorpora D.E.Schnell
- S. flava var. rugelii (Shuttlew. ex A.DC.) Mast.
- S. flava var. flava (autonym)
- Sarracenia leucophylla
- Sarracenia minor
- S. minor var. minor (autonym)
- S. minor var. minor f. viridescens S.McPherson & D.E.Schnell
- S. minor var. okefenokeensis D.E.Schnell
- S. minor var. minor (autonym)
- Sarracenia oreophila
- S. oreophila var. oreophila (autonym)
- S. oreophila var. ornata S.McPherson & D.E.Schnell
- Sarracenia psittacina
- S. psittacina var. psittacina (autonym)
- S. psittacina var. psittacina f. viridescens S.McPherson & D.E.Schnell
- S. psittacina var. okefenokeensis S.McPherson & D.E.Schnell
- S. psittacina var. okefenokeensis f. luteoviridis S.McPherson & D.E.Schnell
- S. psittacina var. psittacina (autonym)
- Sarracenia purpurea
- S. purpurea subsp. purpurea (autonym)
- S. purpurea subsp. purpurea f. heterophylla (Eaton) Fern.
- S. purpurea subsp. venosa (Raf.) Wherry
- S. purpurea subsp. venosa var. venosa (autonym)
- S. purpurea subsp. venosa var. venosa f. pallidiflora S.McPherson & D.E.Schnell
- S. purpurea subsp. venosa var. burkii D.E.Schnell
- S. purpurea subsp. venosa var. burkii f. luteola R.L.Hanrahan & J.Miller
- S. purpurea subsp. venosa var. montana D.E.Schnell & R.O.Determann
- S. purpurea subsp. venosa var. venosa (autonym)
- S. purpurea subsp. purpurea (autonym)
- Sarracenia rubra
- S. rubra subsp. rubra (autonym)
- S. rubra subsp. alabamensis (Case & R.B.Case) S.McPherson & D.E.Schnell[nb b]
- S. rubra subsp. gulfensis D.E.Schnell
- S. rubra subsp. gulfensis f. luteoviridis S.McPherson & D.E.Schnell
- S. rubra subsp. jonesii (Wherry) Wherry
- S. rubra subsp. jonesii f. viridescens S.McPherson & D.E.Schnell
- S. rubra subsp. wherryi (Case & R.B.Case) D.E.Schnell
- S. rubra "Incompletely diagnosed taxon from Georgia and South Carolina" (Undescribed, but see note below)
Note: The entity McPherson and Schnell referred to as S. rubra "Incompletely diagnosed taxon from Georgia and South Carolina" has since been established as Sarracenia rubra subsp. viatorum B.Rice.[17]
Hybrids
Sarracenia species hybridize and produce fertile offspring freely, making proper classification difficult. Sarracenia hybrids are able to hybridize further, giving the possibility of hundreds of different hybrids that have multiple species in varying amounts in their ancestry. Since many species ranges overlap, natural hybrids are relatively common. As a result, initial classification included many of these hybrids as separate species. A recent census of the number of hybrids and cultivars of Sarracenia species revealed about 100 unique hybrids and cultivars in cultivation.[15] Many hybrids of Sarracenia are still commonly referred to by their obsolete species names, particularly in horticulture. These hybrids are all popularly cultivated by carnivorous plant enthusiasts, and there are consequently a huge number of hybrids and cultivars, most bred for showy pitchers.
Some of the more common named hybrids include:
- Sarracenia × catesbaei = S. flava × S. purpurea
- Sarracenia × moorei = S. flava × S. leucophylla
- Sarracenia × popei = S. flava × S. rubra
- Sarracenia × harperi = S. flava × S. minor
- Sarracenia × alava = S. flava × S. alata
- Sarracenia × mitchelliana = S. purpurea × S. leucophylla
- Sarracenia × exornata = S. purpurea × S. alata
- Sarracenia × chelsonii = S. purpurea × S. rubra
- Sarracenia × swaniana = S. purpurea × S. minor
- Sarracenia × courtii = S. purpurea × S. psittacina
- Sarracenia × pureophila = S. purpurea × S. oreophila
- Sarracenia × readii = S. leucophylla × S. rubra
- Sarracenia × farnhamii = S. leucophylla × S. rubra
- Sarracenia × excellens = S. leucophylla × S. minor
- Sarracenia × areolata = S. leucophylla × S. alata
- Sarracenia × wrigleyana = S. leucophylla × S. psittacina
- Sarracenia × ahlesii = S. alata × S. rubra
- Sarracenia × rehderi = S. rubra × S. minor
- Sarracenia × gilpini = S. rubra × S. psittacina
- Sarracenia × formosa = S. minor × S. psittacina
Botanical history
Sarracenia were known to Europeans as early as the 16th century, within a century of
The name Sarracenia was first employed by
Cultivation
Sarracenia are considered easy to grow and are widely propagated and cultivated by gardeners and carnivorous plant enthusiasts. Several hybrids between the very hardy S. purpurea and showy species like S. leucophylla are becoming common in garden centers in North America and Europe.
Sarracenia require constantly moist-wet, nutrient free acidic soil. This is most often achieved with a potting mix consisting of peat moss mixed with sand or perlite. As their roots are sensitive to nutrients and minerals, only pure water, such as distilled, rain, or reverse osmosis water, can be used to water them. Sarracenia prefer sunny conditions during their growing season but require a dormancy period, with decreased light and temperatures, of a few months in the winter.
Propagation
Sarracenia do not self-pollinate and therefore require hand pollination or access to natural pollinators such as bees. Sarracenia pollen remains potent for several weeks when refrigerated, and so is stored by cultivators and used to pollinate later-flowering species. Given that all Sarracenia hybrids are fertile and will hybridize further, this characteristic allows cultivators to produce a limitless number of variants through hybridization.
The copious seeds store well if kept dry. In climates or seasons that cannot provide the cold, damp period of stratification required by the seeds for germination, growers mimic this condition by placing the seeds in a refrigerator for 2–6 weeks, depending on species. The seeds are sown on the surface of their substrate and germinate when transferred to warmer, bright conditions. Sarracenia seedlings all look alike for the first two or three years; the plants reach maturity after four or five years. Regular fertilization (twice a month between April and September) with a balanced fertilizer at the rate of 1 teaspoon per gallon (using a 15-16-17 peat-lite or similar fertilizer) will speed their growth and time to maturity. It is advisable to leach regularly with pure water to prevent the buildup of solutes (fertilizer salts) in the soil. Deep water in a potted plant keeps the soil too waterlogged for proper root functioning.
Mature Sarracenia are commonly propagated by division. Their rhizomes extend and produce new crowns of pitchers over the course of a few growing seasons, and cultivators divide and separate the rhizomes during the plant's winter dormancy or early in the growing season. This technique is also used to separate sections of rhizomes which have no pitchers: when re-potted, the section usually generates a new crown of pitchers. A further technique is employed to encourage new crowns to appear which does not involve division of the rhizome: small notches up to 5 mm deep are cut into the top of the rhizome, whereupon a new crown frequently develops at the site of the notch.
AGM cultivars
The following have won the Royal Horticultural Society's Award of Garden Merit:
See also
Notes
- a.botanical code.[31]
References
- ^ S2CID 38319708.
- ^ PMID 28222171.
- ^ a b Cumbee, Joe (1995). "Sarracenia flava Seed Data". Carnivorous Plant Newsletter. 24: 110–111.
- ^ Brittnacher, John. "Growing Sarracenia from seed". Retrieved 2017-05-20.
- JSTOR 2483737. Retrieved 26 April 2016.
- JSTOR 2481882.
- ^ Hartmeyer, Siegfried. "Sarracenia purpurea "in the wild" in Switzerland". hartmeyer.de. Archived from the original on 23 November 2015. Retrieved 23 November 2015.
- ^ a b Groves, M., ed. 1993. Horticulture, Trade and Conservation of the Genus Sarracenia in the Southeastern States of America: Proceedings of a Meeting Held at the Atlanta Botanical Garden, September 22–23, 1993, 17pp.
- ^ Robbins, C. S. 1998. Examination of the U.S. Pitcher-plant Trade With a Focus on the White-topped Pitcher-plant. Traffic Bulletin. Excerpts, Vol. 17, No. 2 (June 1998)
- ^ U.S. Fish and Wildlife Service. 1991. U.S. CITES Permits and Export Figures for Sarracenia 1990–1991. Washington, DC.
- ^ Brittnacher, John. "ICPS Conservation Projects". Retrieved 2017-05-20.
- ^ Cronquist, Arthur. (1981). An integrated system of classification of flowering plants. New York: Columbia University Press.
- ^ Angiosperm Phylogeny Group. (2003). An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society, 141: 399–436.
- ^ a b Rice, Barry. (2008). Sarracenia species lists. Sarracenia.com FAQ. Accessed: 10-10-2008.
- ^ a b Barthlott, W., S. Porembski, R. Seine, and I. Theisen. (2007). The Curious World of Carnivorous Plants. Portland: Timber Press.
- ^ McPherson, S. & D. Schnell 2011. Sarraceniaceae of North America. Redfern Natural History Productions Ltd., Poole.
- .
- ^ S2CID 247344089.
- ^ ISBN 0-89815-915-6.
- .
- ^ Mellichamp, T. Lawrence; Case, Frederick W. (2009). "Sarracenia". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 8. New York and Oxford: Oxford University Press. Retrieved 2018-10-06 – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
- ^ "Sarracenia 'Anna Carlisle'". RHS. Retrieved 5 March 2021.
- ^ "Sarracenia 'Colin Clayton'". RHS. Retrieved 5 March 2021.
- ^ "Sarracenia 'Dixie Lace'". RHS. Retrieved 5 March 2021.
- ^ "Sarracenia 'Jenny Helen'". RHS. Retrieved 5 March 2021.
- ^ "Sarracenia 'Juthatip Soper'". RHS. Retrieved 5 March 2021.
- ^ "Sarracenia 'Vogel'". RHS. Retrieved 5 March 2021.
- ^ "Sarracenia × catesbaei 'Violet'". RHS. Retrieved 5 March 2021.
- ^ "Sarracenia × mitchelliana 'Victoria Morley'". RHS. Retrieved 5 March 2021.
- ^ "Sarracenia × moorei 'Brooks's Hybrid'". RHS. Retrieved 5 March 2021.
- ^ a b Rice, B (2012). "Book review". Carnivorous Plant Newsletter. 41 (2): 83–87.
Further reading
- Schnell, Donald E. 2002. Carnivorous Plants of the United States and Canada. Portland. ISBN 0-88192-540-3
- Schnell, Stewart McPherson, Donald E. (2011). Sarraceniaceae of North America. Poole: Redfern Natural History Productions. ISBN 0-9558918-6-8.
External links
- Sarracenia Taxonomy by Barry Rice
- Sarracenia – the Pitcher Plants by the Botanical Society of America
- Sarracenia Growing Guide and Distribution Map by Tom's Carnivores
- Growing Sarracenia by the International Carnivorous Plant Society
- The Inner World of Sarracenia by the John Innes Centre