Philcoxia
Encyclopedia
Philcoxia is a genus
of three rare plant species in the Plantaginaceae
that are endemic to Brazil
and resemble terrestrial species of the genus Utricularia. The genus, formally described in 2000, consists of the species P. bahiensis
, P. goiasensis, and P. minensis, each named for the Brazilian state to which it is endemic. The species are characterized by subterranean stems, peltate
leaves at or below the soil surface, and five-lobed calyces. Their habitat has been reported as areas of white sand in the midst of cerrado
vegetation at an elevation
between 800 and 1450 m. Initial descriptions of the genus included suspicions that the plethora of stalked capitate glands on the upper surfaces of leaves was an indication that these species may be carnivorous
. A study published in 2007 tested P. minensis for protease
activity, a typical test for the carnivorous syndrome, and could detect none. The genus epithet honors David Philcox, a botanist at Kew Gardens
who worked extensively in tropical Scrophulariaceae
.
or annual
herbs that reside in oases of deep white sand surrounded by the typical vegetation of the cerrado
ecoregion. They are no more than 26 cm tall with 5-10 leaves. Zigzag-shaped raceme
s are produced from upright stems and account for the height of the species. These monotelic inflorescence
s are leafless and produce pale blue to lilac flowers (P. goiasensis has a yellow corolla tube). The flowers possess monothecous, glabrous anthers, which are unusual in the family. The upper surface of the leaves are covered with stalked capitate glands that are also seen in many carnivorous plant genera.
. Peter Taylor et al. later noted in the 2000 description of the genus that its affinities should include the genera Gratiola
and Dopatrium in the tribe Gratioleae of the Scrophulariaceae. The Angiosperm Phylogeny Group
later changed the circumscription of the Scrophulariaceae so that the tribe Gratioleae is now within the Plantaginaceae
. In 2004, E. Fischer also placed in tribe Gratioleae, but also placed it within the informally recognized subtribe Dopatriinae, which was described as also containing the genera Deinostema, Dopatrium, Hydrotriche, and Limnophila, which consist mostly of aquatic species. In 2007, an extensive study and phylogenetic analysis by Peter Fritsch et al. confirmed that Philcoxia should be placed in the tribe Gratioleae, but it is in fact not as closely related to Gratiola and the Dopatriinae as was previously assumed.
of Bahia
. One collection was sent to Kew Gardens
for naming. Because of its placentation
, the specimen was determined to be a member of the Scrophulariaceae (later Plantaginaceae sensu APG II) despite its appearance close to that of terrestrial Utricularia. Material of this specimen had been sent to Vinícius Souza, who was working on the Scrophulariaceae of Brazil. Souza recognized the material as congeneric with a plant collected in 1981 from the Serra do Cabral of the Brazilian state Minas Gerais
. The collection was made by a group from the University of São Paulo
. The site location of that collection was not identified and subsequent expeditions were unable to relocate the species until 2007.
However, an even earlier specimen now recognized as P. goiasensis had been collected in 1966 near Posse
in the northeastern state of Goiás
by a group from the New York Botanical Garden
. Initially, the specimen had been determined to be a member of the Lentibulariaceae
. Peter Taylor and David Philcox later concluded that this represented an undescribed genus of Scrophulariaceae. A description and illustration was completed and set aside for over twenty years. Then, in 1994, Taylor showed the specimen and description to Ray Harley in preparation for publication. Harley, who had been involved in the early 1990s discovery of P. bahiensis, recognized Taylor's materials as another species of the as of yet undescribed genus.
s. In Taylor's publication, the authors noted that field observations had not indicated that there was any carnivorous function of the leaves, citing a lack of captured prey as evidence.
Peter Fritsch and his coauthors decided to do a more comprehensive test for carnivory on P. minensis after they observed nematode
worms on leaf surfaces. The similarity between the habitat for Philcoxia species and that of Genlisea
and their similar subterranean leaves and stems spurred the team's decision to test for potential carnivory in the field and in situ. They tested for a protease
enzyme that is one of the enzymes found in other carnivorous plants and is responsible for breaking down captured prey. They hypothesized that Philcoxia could be carnivorous, capturing nematodes and possibly soil microbes like Utricularia and Genlisea do. Ultimately, Fritsch's study concluded that while no protease activity was detected, this fact does not rule out the possibility that the genus may be carnivorous in some other way. They note that there are many possibilities, such as seasonal carnivory or the unusual growth form being an adaptation to the heat and sun, and more study is needed before precise conclusions can be reached.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of three rare plant species in the Plantaginaceae
Plantaginaceae
Plantaginaceae Juss. or plantain family, are a family of flowering plants in the order Lamiales. The type genus is Plantago L..In older classifications it used to be the only family of the order Plantaginales, but numerous phylogenetic studies, summarized by the Angiosperm Phylogeny Group, have...
that are endemic to Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
and resemble terrestrial species of the genus Utricularia. The genus, formally described in 2000, consists of the species P. bahiensis
Philcoxia bahiensis
Philcoxia bahiensis is a rare plant species in the Plantaginaceae that is endemic to the Brazilian state of Bahia. It was first discovered collected by a local resident, Wilson Ganev, in August 1992 from the Serra do Atalho in the Piatã municipality. That collection was sent to Kew Gardens for naming...
, P. goiasensis, and P. minensis, each named for the Brazilian state to which it is endemic. The species are characterized by subterranean stems, peltate
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
leaves at or below the soil surface, and five-lobed calyces. Their habitat has been reported as areas of white sand in the midst of cerrado
Cerrado
The Cerrado, is a vast tropical savanna ecoregion of Brazil, particularly in the states of Gioas and Minas Gerais...
vegetation at an elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
between 800 and 1450 m. Initial descriptions of the genus included suspicions that the plethora of stalked capitate glands on the upper surfaces of leaves was an indication that these species may be carnivorous
Carnivorous plant
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...
. A study published in 2007 tested P. minensis for protease
Protease
A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....
activity, a typical test for the carnivorous syndrome, and could detect none. The genus epithet honors David Philcox, a botanist at Kew Gardens
Royal Botanic Gardens, Kew
The Royal Botanic Gardens, Kew, usually referred to as Kew Gardens, is 121 hectares of gardens and botanical glasshouses between Richmond and Kew in southwest London, England. "The Royal Botanic Gardens, Kew" and the brand name "Kew" are also used as umbrella terms for the institution that runs...
who worked extensively in tropical Scrophulariaceae
Scrophulariaceae
Scrophulariaceae, the figwort family, are a family of flowering plants. The plants are annual or perennial herbs with flowers with bilateral or rarely radial symmetry. Members of the Scrophulariaceae have a cosmopolitan distribution, with the majority found in temperate areas, including...
.
Description
Members of the genus are small perennialPerennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
or annual
Annual plant
An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...
herbs that reside in oases of deep white sand surrounded by the typical vegetation of the cerrado
Cerrado
The Cerrado, is a vast tropical savanna ecoregion of Brazil, particularly in the states of Gioas and Minas Gerais...
ecoregion. They are no more than 26 cm tall with 5-10 leaves. Zigzag-shaped raceme
Raceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
s are produced from upright stems and account for the height of the species. These monotelic inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
s are leafless and produce pale blue to lilac flowers (P. goiasensis has a yellow corolla tube). The flowers possess monothecous, glabrous anthers, which are unusual in the family. The upper surface of the leaves are covered with stalked capitate glands that are also seen in many carnivorous plant genera.
Taxonomy
The nature of Philcoxias highly specialized morphology has led to confusion about its proper taxonomic placement. In 1996, before Philcoxia was even formally published as a taxon, it had been placed by Vinícius Souza in the tribe Scrophularieae of the ScrophulariaceaeScrophulariaceae
Scrophulariaceae, the figwort family, are a family of flowering plants. The plants are annual or perennial herbs with flowers with bilateral or rarely radial symmetry. Members of the Scrophulariaceae have a cosmopolitan distribution, with the majority found in temperate areas, including...
. Peter Taylor et al. later noted in the 2000 description of the genus that its affinities should include the genera Gratiola
Gratiola
Gratiola is a genus of plants in the Plantaginaceae family. Most species are known generally as hedgehyssops. The genus was previously included in the Scrophulariaceae .Species include:...
and Dopatrium in the tribe Gratioleae of the Scrophulariaceae. The Angiosperm Phylogeny Group
Angiosperm Phylogeny Group
The Angiosperm Phylogeny Group, or APG, refers to an informal international group of systematic botanists who came together to try to establish a consensus on the taxonomy of flowering plants that would reflect new knowledge about plant relationships discovered through phylogenetic studies., three...
later changed the circumscription of the Scrophulariaceae so that the tribe Gratioleae is now within the Plantaginaceae
Plantaginaceae
Plantaginaceae Juss. or plantain family, are a family of flowering plants in the order Lamiales. The type genus is Plantago L..In older classifications it used to be the only family of the order Plantaginales, but numerous phylogenetic studies, summarized by the Angiosperm Phylogeny Group, have...
. In 2004, E. Fischer also placed in tribe Gratioleae, but also placed it within the informally recognized subtribe Dopatriinae, which was described as also containing the genera Deinostema, Dopatrium, Hydrotriche, and Limnophila, which consist mostly of aquatic species. In 2007, an extensive study and phylogenetic analysis by Peter Fritsch et al. confirmed that Philcoxia should be placed in the tribe Gratioleae, but it is in fact not as closely related to Gratiola and the Dopatriinae as was previously assumed.
Botanical history
The first recognized specimens of Philcoxia (P. bahiensis) were collected by local resident Wilson Ganev in August 1992 from the Serra do Atalho in the municipality of PiatãPiatã, Bahia
Piatã is a municipality in the state of Bahia in Brazil. The population in 2003 is 19,320 and the area is 1,513.8 km² The elevation is 1,268 m.-External links:*http://www.citybrazil.com.br/ba/piata/...
of Bahia
Bahia
Bahia is one of the 26 states of Brazil, and is located in the northeastern part of the country on the Atlantic coast. It is the fourth most populous Brazilian state after São Paulo, Minas Gerais and Rio de Janeiro, and the fifth-largest in size...
. One collection was sent to Kew Gardens
Royal Botanic Gardens, Kew
The Royal Botanic Gardens, Kew, usually referred to as Kew Gardens, is 121 hectares of gardens and botanical glasshouses between Richmond and Kew in southwest London, England. "The Royal Botanic Gardens, Kew" and the brand name "Kew" are also used as umbrella terms for the institution that runs...
for naming. Because of its placentation
Placentation
In biology, placentation refers to the formation, type and structure, or arrangement of placentas. The function of placentation is to transfer nutrients from maternal tissue to a growing embryo...
, the specimen was determined to be a member of the Scrophulariaceae (later Plantaginaceae sensu APG II) despite its appearance close to that of terrestrial Utricularia. Material of this specimen had been sent to Vinícius Souza, who was working on the Scrophulariaceae of Brazil. Souza recognized the material as congeneric with a plant collected in 1981 from the Serra do Cabral of the Brazilian state Minas Gerais
Minas Gerais
Minas Gerais is one of the 26 states of Brazil, of which it is the second most populous, the third richest, and the fourth largest in area. Minas Gerais is the Brazilian state with the largest number of Presidents of Brazil, the current one, Dilma Rousseff, being one of them. The capital is the...
. The collection was made by a group from the University of São Paulo
University of São Paulo
Universidade de São Paulo is a public university in the Brazilian state of São Paulo. It is the largest Brazilian university and one of the country's most prestigious...
. The site location of that collection was not identified and subsequent expeditions were unable to relocate the species until 2007.
However, an even earlier specimen now recognized as P. goiasensis had been collected in 1966 near Posse
Posse, Goiás
Posse is a small town and municipality in northeastern Goiás state, Brazil.-Geography:It is located northeast of Brasília, 24 km. from the state boundary with Bahia, on interstate highway BR-020...
in the northeastern state of Goiás
Goiás
Goiás is a state of Brazil, located in the central part of the country. The name Goiás comes from the name of an indigenous community...
by a group from the New York Botanical Garden
New York Botanical Garden
- See also :* Education in New York City* List of botanical gardens in the United States* List of museums and cultural institutions in New York City- External links :* official website** blog*...
. Initially, the specimen had been determined to be a member of the Lentibulariaceae
Lentibulariaceae
Lentibulariaceae is a family of carnivorous plants containing three genera, Genlisea, the corkscrew plants, Pinguicula, the butterworts, and Utricularia, the bladderworts....
. Peter Taylor and David Philcox later concluded that this represented an undescribed genus of Scrophulariaceae. A description and illustration was completed and set aside for over twenty years. Then, in 1994, Taylor showed the specimen and description to Ray Harley in preparation for publication. Harley, who had been involved in the early 1990s discovery of P. bahiensis, recognized Taylor's materials as another species of the as of yet undescribed genus.
Carnivory
Peter Taylor, in his 2000 description of the genus, suggested that the morphology Philcoxia resembles that of the carnivorous Lentibulariaceae and the relatively unrelated Droseraceae is some aspects. The upper surface of the leaves are also covered in stalked capitate glands similar to those seen in other carnivorous plantCarnivorous plant
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...
s. In Taylor's publication, the authors noted that field observations had not indicated that there was any carnivorous function of the leaves, citing a lack of captured prey as evidence.
Peter Fritsch and his coauthors decided to do a more comprehensive test for carnivory on P. minensis after they observed nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
worms on leaf surfaces. The similarity between the habitat for Philcoxia species and that of Genlisea
Genlisea
Genlisea is a genus of carnivorous plants also known as corkscrew plants. The 21 species grow in wet terrestrial to semi-aquatic environments distributed throughout Africa and Central and South America. The plants use highly modified underground leaves to attract, trap and digest minute...
and their similar subterranean leaves and stems spurred the team's decision to test for potential carnivory in the field and in situ. They tested for a protease
Protease
A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....
enzyme that is one of the enzymes found in other carnivorous plants and is responsible for breaking down captured prey. They hypothesized that Philcoxia could be carnivorous, capturing nematodes and possibly soil microbes like Utricularia and Genlisea do. Ultimately, Fritsch's study concluded that while no protease activity was detected, this fact does not rule out the possibility that the genus may be carnivorous in some other way. They note that there are many possibilities, such as seasonal carnivory or the unusual growth form being an adaptation to the heat and sun, and more study is needed before precise conclusions can be reached.
External links
- Plantaginaceae at the Angiosperm Phylogeny WebsiteAngiosperm Phylogeny WebsiteAngiosperm Phylogeny Website is a well-known web site dedicated to research on Angiosperm phylogeny and taxonomy.The site is hosted by the Missouri Botanical Garden website and maintained by researcher Peter F. Stevens, who is a member of the Angiosperm Phylogeny Group...
. Version 8, June 2007.