Drosera regia

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Drosera regia
DroseraRegia.jpg
Several plants in cultivation
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Caryophyllales
Family: Droseraceae
Genus: Drosera
Subgenus: Drosera subg. Regiae
Seine & Barthlott
Species:
D. regia
Binomial name
Drosera regia
Synonyms
  • Freatulina regia(Stephens) Chrtek & Slavíková

Drosera regia, commonly known as the king sundew, is a carnivorous plant in the sundew genus Drosera that is endemic to a single valley in South Africa. The genus name Drosera comes from the Greek word droseros, meaning "dew-covered". The specific epithet regia is derived from the Latin for "royal", a reference to the "striking appearance" of the species. Individual leaves can reach 70 cm (28 in) in length. It has many unusual relict characteristics not found in most other Drosera species, including woody rhizomes, operculate pollen, and the lack of circinate vernation in scape growth. All of these factors, combined with molecular data from phylogenetic analysis, contribute to the evidence that D. regia possesses some of the most ancient characteristics within the genus. Some of these are shared with the related Venus flytrap (Dionaea muscipula), which suggests a close evolutionary relationship.

Contents

The tentacle-covered leaves can capture large prey, such as beetles, moths, and butterflies. The tentacles of all Drosera species have special stalked glands on the leaf's upper surface that produce a sticky mucilage. The leaves are considered active flypaper traps that respond to captured prey by bending to surround it. In its native fynbos habitat, the plants compete for space with native marsh grasses and low evergreen shrubs. Of the two known populations of D. regia, the higher elevation site appears to be overgrown and is essentially extirpated. The lower elevation site is estimated to have about 50 mature plants, making it the most endangered Drosera species, since it is threatened with extinction in the wild. It is often cultivated by carnivorous plant enthusiasts, and a single cultivar has been registered.

Description

Detail of a leaf Drosera regia leaf Darwiniana.jpg
Detail of a leaf
A leaf wrapped around prey Drosera regia with prey 2.jpg
A leaf wrapped around prey
Detail of a flower Drosera regia - open and closed flowers without spider web.jpg
Detail of a flower

Drosera regia plants are fairly large herbs that produce horizontal woody rhizomes and a crown of large, linear leaves up to 70 cm (28 in) long and 2 cm (0.8 in) wide. The leaves possess stalked glands (tentacles) on the upper surface of the lamina along nearly the entire length of the leaf. The leaves lack petioles and stipules, emerging by circinate vernation (uncurling) and tapering to a filiform point. The tentacles and the leaf itself are capable of responding to prey by bending toward insects trapped in the sticky mucilage produced by the glands. Leaves are even capable of folding over themselves several times. Each leaf can possess thousands of tentacles, which can aid in the retention of larger prey when combined with the leaf wrapping tightly around captured insects. In its native habitat, D. regia has been known to capture large beetles, moths and butterflies. Plants go dormant during the colder season and form a dormant bud, consisting of a tight cluster of short, immature leaves. Plants begin to break dormancy in mid-July with a typical growing season lasting from October to April, though this is variable and plants can continue growing year-round without dormancy. [1] [2] [3] Individual leaves die back but remain attached to the short stem, clothing the bottom portion of the plant in the blackened dead leaves of former years. [4]

The woody rhizomes produced by the plant are one of the unusual characteristics that it shares only with D. arcturi in the genus; the absence of woody rhizomes in all other Drosera is often cited as an indication of the presumed ancient lineage of D. regia and D. arcturi. Drosera regia also produces relatively few thick, fleshy roots, which possess root hairs along the terminal 15 cm (6 in). Asexual reproduction of mature plants usually occurs after flowering with new plants arising from the rhizome and roots. After a fire, undamaged roots will often re-sprout new plants. [1] [2]

Drosera regia flowers in January and February, producing scapes up to 40 cm (16 in) long. The scapes emerge vertically, lacking the circinate vernation of its leaves and all other scapes of the genus Drosera, with the exception of D. arcturi. The scapes consist of two primary branches and bear 5 to 20 (sometimes 30) unscented pink flowers with 2–3 cm (0.8–1.2 in) long petals. Bracts are small, bearing some reduced tentacles. Each flower has three unbranched, spreading styles emerging from the top of the ovary and extending beyond the five erect stamens (15 mm long), which surround the ovary. This arrangement minimizes the chance of self-fertilisation. Studies have shown that the operculate pollen shed in tetrads (fused groups of four pollen grains), characteristics that are similar in the related Dionaea muscipula (the Venus flytrap) and Aldrovanda vesiculosa , is incompatible with clones, failing to produce seed when plants are self-fertilised. Seeds are brown to black, linear and ornamented with fine network-like markings, and 2 mm long and 0.5 mm in diameter. Seed is shed by the end of March. [1] [2] [4] [5]

The unusual characteristics that set it apart from other species in the genus include the woody rhizome, undivided styles, and the operculate pollen. [2] [6] Drosera regia shares other features with the robust Tasmanian form of D. arcturi, including the lack of stipules and petioles and the non-circinate growth of the scape. [1]

It has a diploid chromosome number of 2n = 34, which is unusual for the genus Drosera and closer to the diploid chromosome number of the Venus flytrap (Dionaea muscipula), another member of the Droseraceae. [7] [8] Variable chromosome counts for Dionaea from multiple studies include 2n = 30, 32, and 33. Of the Drosera species with known chromosome counts, most are a multiple of x = 10. Based on an extensive review of karyotype studies, the botanist Fernando Rivadavia suggested that the base chromosome number for the genus could be 2n = 20, a number that many Drosera species share including the widespread D. rotundifolia . Exceptions to this base number include the Australian, New Zealand and Southeast Asian Drosera, which have chromosome numbers ranging from 2n = 6 to 64. [9]

Distribution and habitat

Drosera regia is endemic to South Africa and has only ever been found at two sites at elevations of 500 and 900 m (1,600 and 3,000 ft) in the Bainskloof Range near Wellington, Western Cape in South Africa. Despite extensive exploration, D. regia has not been found at any similar location in neighbouring valleys. Small morphological variations such as broader leaves have been recorded from these two small populations, which are restricted to an area of just a few hundred square meters. Drosera regia is found in a natural fynbos vegetation amongst dense marshy grasses. The fynbos habitat is similar to a low or medium shrubland or heathland, dominated by low evergreen shrubs. [1] [3]

The lower elevation site where D. regia is found is characterised by permanently damp soils consisting mostly of a gravel bench formed from a creek bed. The plants grow in a peaty quartzite sand, often with a gravel cover. Rhizomes of mature plants grow above ground and among associated grasses and sedges when gravel is absent and below ground when there is a gravel cover present. Associated vegetation included species of Leucadendron and members of the families Cyperaceae, Iridaceae, and Restionaceae. The habitat of D. regia depends on periodic fire sweeping through and keeping the larger plants from choking out D. regia. Frost occurs infrequently in the valley. [1]

Conservation status

In a 2009 report of a 2006 trip, botanist Andreas Fleischmann noted that the higher elevation site is overgrown with plants of the family Restionaceae and he could not locate any remaining D. regia. The lower elevation site was in a similar state, but he recorded approximately 50 mature plants, making this one of the most critically endangered Drosera species. [10] While D. regia has not been evaluated under the current International Union for the Conservation of Nature and Natural Resources (IUCN) standards for a rating on the Red List of Threatened Species, the International Carnivorous Plant Society recognised D. regia on their list of imperiled carnivorous plant species. [11] Drosera regia was also listed as "rare" on an early IUCN report in 1997, [12] but these earlier IUCN assessments were often poorly documented and are thus not relied upon today. [13] Several other authors have identified how rare D. regia is in the wild, even calling it "threatened with extinction". [14]

The short-term prognosis for natural populations of D. regia was greatly improved when a fire swept through its habitat in 2015. A team from Stellenbosch Botanical Gardens found new populations in the lower elevation zone and rediscovered plants in the higher elevation zone. [15]

Taxonomy and botanical history

Drosera regia was originally described by South African botanist Edith Layard Stephens in 1926. [16] [17] The binomial name Drosera regia is derived from the Greek word droseros, meaning "dew-covered" [14] and the specific epithet regia comes from the Latin for "royal", a reference to what Stephens described as its "striking appearance". [4] The genus is collectively referred to as the sundews, while Drosera regia is commonly referred to as the king sundew. [14] Stephens was informed about this new species by Mr. J. Rennie, who had found several plants growing by a stream in the upper end of "Baviaans Kloof" on Easter in 1923. Additional specimens were located directly above this site on a plateau between South Ridge Peak and Observation Point. A second population was located in 1926 about 6.5 km (4 mi) away below the Slanghoek Peak near the headwaters of the Witte River. [4]

Stephens placed D. regia in section Psychophila Planch., which at that time included D. arcturi , D. stenopetala , and D. uniflora , though she noted that the many-flowered inflorescence was unusual for this group. [1] In 1970, the South African botanist Anna Amelia Obermeyer suggested that D. regia did not fit into any of the taxonomic groups established by Ludwig Diels in his 1906 monograph on the family. Obermeyer noted the unusual characteristics that set D. regia apart from any other Drosera species: the operculate pollen, circinate leaf vernation, undivided styles, and woody rhizomes. [2] In 1994, Rüdiger Seine and Wilhelm Barthlott proposed classifying D. regia as the sole species in a new subgenus, Drosera subg. Regiae, to "give adequate recognition to the isolated position of D. regia within the genus." [6] This taxonomic position was affirmed by Jan Schlauer in his dichotomous key and taxonomic revisions published in 1996. [18] Also in 1996 two Czech researchers, Jindřich Chrtek and Zdeňka Slavíková, proposed changes to the taxonomy of the genus by splitting D. regia off into its own, monotypic genus, Freatulina. Chrtek and Slavíková cited the many morphological differences between D. regia and every other member of the genus Drosera in support of their decision to make this taxonomic split. [19] They reaffirmed their taxonomic opinions in a 1999 article that also split the tuberous Drosera, members of the subgenus Ergaleium , to Johann Georg Christian Lehmann's resurrected genus Sondera. [20] These taxonomic revisions, however, have not gained any support, being rejected or largely ignored by recent publications on the genus. [14] [21]

Evolutionary relationships

The most parsimonious cladogram based on the combination of rbcL and 18S rDNA gene sequences from the taxa used in the analysis. Drosophyllum , which is sometimes placed in the family Droseraceae, was used as part of the outgroup. [22]

Phylogenetic analysis of morphological characteristics and gene sequences has supported the basal position within the genus long suspected of D. regia, often regarded as the most ancient of all extant Drosera species. [3] Its distinct morphology and unique relict characteristics, ones it likely shared with the common ancestor of all Drosera such as the operculate pollen, led early researchers to suggest its ancient position in the genus. The first cladistic analysis based on rbcL and morphological data confirmed these ideas and suggested that D. regia formed a clade sister to all other Drosera surveyed, with Dionaea muscipula forming a sister clade to all Drosera. [23] Further analysis in 2002 based on the nuclear 18S rDNA, plastid DNA (rbcL, matK, atpB), and morphological data confirmed these relationships, supporting the basal position of D. regia in the genus and its close relationship with Dionaea and Aldrovanda . [24] New analysis in 2003 revealed a close relationship between D. regia and D. arcturi, both of which clustered basally with respect to all other Drosera, suggesting a link between D. regia and all other Drosera through its relationship with D. arcturi. [22]

Evidence for the evolution of "snap-traps" of Dionaea and Aldrovanda from a flypaper trap like D. regia has also emerged and been argued for based on molecular data. The molecular and physiological data implies that the Venus flytrap (Dionaea) and Aldrovanda snap-traps evolved from the flypaper traps of a common ancestor with the Drosera; the living evidence of a link between Drosera and Dionaea is D. regia and its remnant characteristics. In this evolutionary model, pre-adaptations to evolution into snap-traps were identified in several species of Drosera, such as rapid leaf and tentacle movement. The model proposes that plant carnivory by snap-trap evolved from the flypaper traps of Drosera, driven by increasing prey size. Larger prey can easily escape the sticky mucilage of flypaper traps; the evolution of snap-traps would largely prevent escape and kleptoparasitism (theft of prey captured by the plant before it can derive any benefit from it). [24] [25]

Cultivation

D. regia in cultivation Drosera regia Darwiniana.jpg
D. regia in cultivation

Drosera regia cultivation was first attempted prior to the formal description of the species in 1926. The author, Edith Layard Stephens, reported the successful cultivation of D. regia, noting that such success required "a moist and comparatively cool atmosphere", similar to that of its native environment. [4]

Drosera regia is often described as being a difficult species to cultivate, [26] though modern reports on its cultivation have indicated which conditions have led to success for some. For optimal growth, D. regia appears to require good soil drainage and sufficient light levels, and prefers cooler temperatures. Cool nights and warm days have been reported to induce vigorous growth. Asexual propagation is frequently achieved through small root cuttings instead of leaf cuttings, which tend to rot before roots can form. [27] [28] [29] Seed germination occurs as early as 10 days to 3 or 4 weeks with fresh seed, faster than many other Drosera species. Germination is phanerocotylar (non-glandular cotyledons exposed, free from seed coverings), with the first true leaves being alternate in arrangement. [30]

In 2004, William Joseph Clemens registered the only cultivar of this species, D. regia 'Big Easy'. It is reputed to be more robust than other clones of the species and is also more compact with maximum leaf lengths of 23 cm (9 in). Under his culture conditions, 'Big Easy' has also never flowered or gone dormant. Clemens originally obtained his D. regia from a vendor at the International Carnivorous Plant Society conference held in 2000. After sufficient investigation, he registered the new cultivar in a 2004 issue of the Carnivorous Plant Newsletter , the quarterly publication of the International Carnivorous Plant Society. [26]

Related Research Articles

<i>Drosera</i> Genus of carnivorous flowering plants in the family Droseraceae

Drosera, which is commonly known as the sundews, is one of the largest genera of carnivorous plants, with at least 194 species. These members of the family Droseraceae lure, capture, and digest insects using stalked mucilaginous glands covering their leaf surfaces. The insects are used to supplement the poor mineral nutrition of the soil in which the plants grow. Various species, which vary greatly in size and form, are native to every continent except Antarctica.

<span class="mw-page-title-main">Droseraceae</span> Family of carnivorous flowering plants

Droseraceae is a family of carnivorous flowering plants, also known as the sundew family. It consists of approximately 180 species in three extant genera, the vast majority being in the sundew genus Drosera. The family also contains the well-known Venus flytrap and the more obscure waterwheel plant, both of which are the only living species of their respective genera. Representatives of the Droseraceae are found on all continents except Antarctica.

<span class="mw-page-title-main">Venus flytrap</span> Species of carnivorous plant

The Venus flytrap is a carnivorous plant native to the temperate and subtropical wetlands of North Carolina and South Carolina, on the East Coast of the United States. Although various modern hybrids have been created in cultivation, D. muscipula is the only species of the monotypic genus Dionaea. It is closely related to the waterwheel plant and the cosmopolitan sundews (Drosera), all of which belong to the family Droseraceae. Dionaea catches its prey—chiefly insects and arachnids—with a "jaw"-like clamping structure, which is formed by the terminal portion of each of the plant's leaves; when an insect makes contact with the open leaves, vibrations from the prey's movements ultimately trigger the "jaws" to shut via tiny hairs on their inner surfaces. Additionally, when an insect or spider touches one of these hairs, the trap prepares to close, only fully enclosing the prey if a second hair is contacted within (approximately) twenty seconds of the first contact. Triggers may occur as quickly as 1⁄10 of a second from initial contact.

<i>Drosophyllum</i> Genus of carnivorous plants

Drosophyllum is a genus of carnivorous plants containing the single species Drosophyllum lusitanicum, commonly known as Portuguese sundew or dewy pine. In appearance, it is similar to the related genus Drosera, and to the much more distantly related Byblis.

<i>Roridula</i> Insect-trapping shrublet from South Africa

Roridula is a genus of evergreen, insect-trapping shrubs, with two species, of about 1⅓–2 m. It is the only genus in the family Roridulaceae. It has thin, woody, shyly branching, upright, initially brown, later grey stems, with lance- to awl-shaped leaves crowded at their tips. The star-symmetrical flowers consist from the outside in of five, green or reddish, free sepals, alternating with five white, pink or purple, free petals. Further to the middle and opposite the sepals are five stamens with the anthers initially kinked down. These suddenly flip up if the nectar-containing swelling at its base is being touched. The center of the flower is occupied by a superior ovary. The leaves and sepals carry many sticky tentacles of different sizes, that trap insects. Roridula does not break down the insect proteins, but bugs of the genus Pameridea prey on the trapped insects. These later deposit their feces on the leaves, which take up nutrients from the droppings. The species can be found in the Western Cape province of South Africa. They are commonly known as dewstick or fly bush in English and vlieëbos or vlieëbossie in Afrikaans.

<i>Drosera capensis</i> Species of carnivorous plant

Drosera capensis, commonly known as the Cape sundew, is a small rosette-forming carnivorous species of perennial sundew native to the Cape in South Africa. Because of its size, easy-to-grow nature, and the copious amounts of seed it produces, it has become one of the most common sundews in cultivation, and thus, one of the most frequently introduced and naturalised invasive Drosera species.

<i>Drosera adelae</i> Species of carnivorous plant

Drosera adelae, commonly known as the lance-leaved sundew, is a carnivorous plant in the genus Drosera that is endemic to Queensland, Australia.

<i>Aldrovanda</i> Genus of carnivorous plants

Aldrovanda is a genus of carnivorous plants encompassing one extant species and numerous extinct taxa. The genus is named in honor of the Italian naturalist Ulisse Aldrovandi, the founder of the Botanical Garden of Bologna, Orto Botanico dell'Università di Bologna. Aldrovanda vesiculosa has been reported from scattered locations in Europe, Asia, Africa, and Australia.

<span class="mw-page-title-main">Thigmonasty</span> Undirected movement in response to touch or vibration

In biology, thigmonasty or seismonasty is the nastic (non-directional) response of a plant or fungus to touch or vibration. Conspicuous examples of thigmonasty include many species in the leguminous subfamily Mimosoideae, active carnivorous plants such as Dionaea and a wide range of pollination mechanisms.

<i>Drosera anglica</i> Species of carnivorous flowering plant in the family Droseraceae

Drosera anglica, commonly known as the English sundew or great sundew, is a carnivorous flowering plant species belonging to the sundew family Droseraceae. It is a temperate species with a circumboreal range, although it does occur as far south as Japan, southern Europe, and the island of Kauai in Hawaii, where it grows as a tropical sundew. It is thought to originate from an amphidiploid hybrid of D. rotundifolia and D. linearis, meaning that a sterile hybrid between these two species doubled its chromosomes to produce fertile progeny which stabilized into the current D. anglica.

<span class="mw-page-title-main">Carnivorous plant</span> Plants that consume animals

Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods, and occasionally small mammals and birds. They still generate all of their energy from photosynthesis. They have adapted to grow in waterlogged sunny places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic bogs. They can be found on all continents except Antarctica, as well as many Pacific islands. In 1875, Charles Darwin published Insectivorous Plants, the first treatise to recognize the significance of carnivory in plants, describing years of painstaking research.

<i>Drosera erythrorhiza</i> Species of carnivorous plant

Drosera erythrorhiza, the red ink sundew, is a perennial tuberous species in the carnivorous plant genus Drosera that is endemic to Western Australia. It grows in a rosette and is distinguished from the other species in section Erythrorhiza by its many-flowered cymose inflorescences with up to 50 individual flowers. D. erythrorhiza was first described by John Lindley in his 1839 publication A sketch of the vegetation of the Swan River Colony. In 1992, N. G. Marchant and Allen Lowrie described three new subspecies, thus also creating the autonym D. erythrorhiza subsp. erythrorhiza. The subspecies were separated from this variable species mostly by leaf morphology and distribution.

<i>Drosera hamiltonii</i> Species of carnivorous plant

Drosera hamiltonii, the rosy sundew, is a small, compact species in the carnivorous plant genus Drosera and is the only species in the monotypic subgenus Stelogyne. The glandular leaves are about 2 cm (0.8 in) long and arranged in a rosette. In November and December, pink flowers on 30 cm (12 in) tall scapes bloom. It is endemic to coastal swamps in south-west Western Australia. It was first described by Cecil Rollo Payton Andrews in 1903 and placed in section Stelogyne as the only species by Ludwig Diels in 1906. In 1994, Rüdiger Seine and Wilhelm Barthlott suggested D. hamiltonii belonged in their section Drosera, reducing section Stelogyne to synonymy with section Drosera. In 1996, Jan Schlauer revised the genus classification and elevated section Stelogyne to a subgenus, arguing that the unique fused styles requires segregation at more than a sectional rank.

<i>Drosera glanduligera</i> Species of carnivorous plant

Drosera glanduligera, commonly known as the pimpernel sundew or scarlet sundew, is a species of carnivorous plant endemic to southern Australia. It is an ephemeral annual plant that grows in the winter and flowers from August to November.

<i>Drosera uniflora</i> Species of carnivorous plant

Drosera uniflora is a species in the carnivorous plant genus Drosera that is native to southern Chile, Argentina, and the Falkland Islands. It is a tiny sundew with a solitary white flower as its name would suggest. Stalked glands on its leaves, which secrete sticky mucilage at the tips, are used to capture and hold insect prey, from which the plant derives the nutrients it cannot obtain in sufficient quantity from the soil. It was formally described in 1809 by botanist Carl Ludwig Willdenow.

<i>Drosera falconeri</i> Species of carnivorous plant

Drosera falconeri is a carnivorous plant in the family of Droseraceae. It is endemic to the Northern Territory of Australia.

Drosera viridis is a semi-erect or rosetted perennial species in the carnivorous plant genus Drosera. It is known only from Brazil, being found in eastern Paraná and São Paulo and central Santa Catarina at elevations from 550–1,100 m (1,800–3,610 ft). It may, however, also be found in adjacent Argentina, Paraguay, and Uruguay. It typically grows in waterlogged habitats among grasses in white-clayey, reddish lateritic, or humus-rich black-brown soils and is sometimes found submerged with only the leaves above water.

Drosera peruensis is a carnivorous plant of the genus Drosera, commonly known as the Peruvian sundew. This Drosera species was first identified in Peru in 2002 by Tânia Regina dos Santos Silva and Mireya D. Correa following work to update the genus Drosera for the reference text, Flora Neotropica..

<span class="mw-page-title-main">Steel trap (carnivorous plants)</span> Prey capture device of some carnivorous plants

Steel trap is an informal term in the study of comparative plant physiology of the carnivorous plants. "Steel trap", more particularly "active steel trap", refers to prey capture devices such as occur in some members of the family Droseraceae, and in particular in the genera Dionaea and Aldrovanda ("waterwheel"). The term apparently originated with the author Francis Ernest Lloyd in 1942, in which he adopted the overly general term "steel trap" rather than say, "gin trap" or a more adjectival form, for devices such as the lobed trap leaves of Dionaea.

<i>Drosera admirabilis</i> Species of carnivorous plant

Drosera admirabilis, commonly referred to as the "floating sundew", is in the carnivorous us plant family Droseraceae. The nickname "admirabilis" was first used in literature by Paul Debbert in 1987 and was derived from how "admirable" the plant appears when it reaches a fully matured specimen. Structurally similar to Drosera aliciae, and Drosera cuneifolia, the D. admirabilis grows in a single tight rosette-shaped leaf bundle. The leaves widen towards the end and have rounded tips. Leaves lay horizontally under proper lighting conditions. Like many other African sundews, D. admirabilis is a perennial. D. admirabilis has outer tentacles like those of Drosera glanduligera, Drosera sessilifolia and Drosera burmanni which briefly after stimulation bend towards the prey.

References

  1. 1 2 3 4 5 6 7 Gibson, R. 1999. Drosera arcturi in Tasmania and a comparison with Drosera regia. Carnivorous Plant Newsletter , 28(3): 76–80.
  2. 1 2 3 4 5 Obermeyer, A. A. 1970. Droseraceae. In L. E. Codd, B. Winter, D. J. B. Killick, and H. B. Rycroft [eds.], Flora of South Africa, 13: 187–201. Department of Agricultural Technical Services, Pretoria, South Africa.
  3. 1 2 3 McPherson, S. 2008. Glistening Carnivores: The Sticky-leaved Insect-eating Plants. Poole, Dorset, England: Redfern Natural History Productions. pp. 154–157. ISBN   978-0-9558918-1-6
  4. 1 2 3 4 5 Stephens, E. L. 1926. A new sundew, Drosera regia (Stephens), from the Cape Province. Transactions of the Royal Society of South Africa, 13(4): 309–312. doi : 10.1080/00359192509519615
  5. ↑ Takahashi, H. and Sohma, K. 1982. Pollen morphology of the Droseraceae and its related taxa. Science Reports of the Research Institutes Tohoku University, 4th Series, Biology, 38: 81–156.
  6. 1 2 Seine, R., and Barthlott, W. 1994. Some proposals on the infrageneric classification of Drosera L. Taxon, 43: 583–589. ISSN   0040-0262
  7. ↑ Behre, K. 1929. Physiologische und zytologische Untersuchungen über Drosera. Planta, 7: 208–306. (in German) doi : 10.1007/BF01916031
  8. ↑ Kondo, K. 1969. Chromosome numbers of carnivorous plants. Bulletin of the Torrey Botanical Club, 96(3): 322–328. doi : 10.2307/2483737
  9. ↑ Rivadavia, F. 2005. New chromosome numbers for Drosera L. (Droseraceae). Carnivorous Plant Newsletter , 34(3): 85–91.
  10. ↑ Fleischmann, A. 30 April 2009. Wild Drosera regia. CPUK Forum. Retrieved 21 December 2009.
  11. ↑ Rice, B. A. 2003. Appendix: Imperiled Carnivorous Plant Species List. Archived 2009-12-07 at the Wayback Machine International Carnivorous Plant Society. Retrieved 21 December 2009.
  12. ↑ Walter, K. S., and Gillett, H. J. [eds]. 1998. 1997 IUCN Red List of Threatened Plants. International Union for the Conservation of Nature and Natural Resources. p. 240. ISBN   978-2-8317-0328-2
  13. ↑ International Union for Conservation of Nature and Natural Resources. 2010. Red List Overview. Archived 2012-05-27 at the Wayback Machine The IUCN Red List of Threatened Species. Retrieved 9 January 2010.
  14. 1 2 3 4 Barthlott, W., Porembski, S., Seine, R., and Theisen, I. 2007. The Curious World of Carnivorous Plants: A Comprehensive Guide to Their Biology and Cultivation. Portland, Oregon, USA: Timber Press. pp. 94–106. ISBN   978-0-88192-792-4
  15. ↑ Hewitt, Peter (2016-11-04), Drosera regia in South Africa (forum thread), International Carnivorous Plant Society (ICPS), retrieved 2017-06-25
  16. ↑ Schlauer, J. 2009. World Carnivorous Plant List – Nomenclatural Synopsis of Carnivorous Phanerogamous Plants. Archived 2016-09-18 at the Wayback Machine . Retrieved 26 December 2009.
  17. ↑ "Drosera regia". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens . Retrieved 29 December 2009.
  18. ↑ Schlauer, J. 1996. A dichotomous key to the genus Drosera L. (Droseraceae). Carnivorous Plant Newsletter , 25(3): 67–88.
  19. ↑ Chrtek, J., and Slavíková, Z. 1996. Comments on the families Drosophyllaceae and Droseraceae. Journal of the National Museum (Prague), Natural History Series, 165: 139–141.
  20. ↑ Chrtek, J. and Slavíková, Z. 1999. Genera and families of the Droserales order. Novitates Botanicae Universitatis Carolinae, 13: 39–46.
  21. ↑ Rice, B. A. 2006. Growing Carnivorous Plants. Timber Press: Portland, Oregon, USA. pp. 84–85. ISBN   978-0-88192-807-5
  22. 1 2 Rivadavia, F., Kondo, K., Kato, M., and Hasebe, M. 2003. Phylogeny of the sundews, Drosera (Droseraceae), based on chloroplast rbcL and nuclear 18S ribosomal DNA sequences. American Journal of Botany, 90(1): 123–130. doi:10.3732/ajb.90.1.123
  23. ↑ Williams, S. E., Albert, V. A., and Chase, M. W. 1994. Relationships of Droseraceae: a cladistic analysis of rbcL sequence and morphological data. American Journal of Botany, 81(8): 1027–1037. doi : 10.2307/2445297
  24. 1 2 Cameron, K. M., Wurdack, K. J., Jobson, R. W. 2002. Molecular evidence for the common origin of snap-traps among carnivorous plants. American Journal of Botany, 89(9): 1503–1509. doi : 10.3732/ajb.89.9.1503
  25. ↑ Gibson, T. C., and Waller, D. M. 2009. Evolving Darwin's 'most wonderful' plant: ecological steps to a snap-trap. New Phytologist, 183(3): 575–587. doi : 10.1111/j.1469-8137.2009.02935.x PMID   19573135
  26. 1 2 Clemens, W. J. 2004. New Cultivars: Drosera regia 'Big Easy'. Carnivorous Plant Newsletter , 33(3): 83–89.
  27. ↑ Jacobs, P. 1981. On growing Drosera regia. Carnivorous Plant Newsletter , 10(1): 10.
  28. ↑ Ziemer, R. R. 1980. Drosera regia. Carnivorous Plant Newsletter , 9(1): 15.
  29. ↑ Mazrimas, J. 1996. Drosera. Carnivorous Plant Newsletter , 25(3): 95–96.
  30. ↑ Conran, J. G., Jaudzems, V. G., and Hallam, N. D. 1997. Droseraceae germination patterns and their taxonomic significance. Botanical Journal of the Linnean Society, 123: 211–223. doi : 10.1111/j.1095-8339.1997.tb01414.x

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