| Ileostylus micranthus | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Santalales |
| Family: | Loranthaceae |
| Genus: | Ileostylus |
| Species: | I. micranthus |
| Binomial name | |
| Ileostylus micranthus | |
Ileostylus micranthus, commonly known as green mistletoe pikirangi; pirinoa; pirirangi; pirita; small-flowered mistletoe, [1] is a species of mistletoe in the family Loranthaceae.
Ileostylus micranthus is a mistletoe native to New Zealand and the Norfolk Islands. [2] In New Zealand it is also known by its Māori name Pirita. [3]
Mistletoes are stem hemiparasites that live on the limbs of a host tree or shrub and consume water, nutrients transported by water, and organic solutes. The Loranthaceae and Viscaceae are the two main groups of mistletoe. Loranthaceae contains 50 to 80 genera, which are primarily Southern Hemisphere-based. There are six endemic Loranthaceae species in New Zealand. Since European settlement, all have decreased in abundance. Loss of territory and the introduction of herbivores, particularly the Australian brushtail possum, have caused the decline. [4]
Ileostylus micranthus grows in clusters on their host plant with a diameter of at least 2 m. It has opposite pairs of thick, leathery leaves with a leaf length between 2 cm and 8 cm and a width of 1 to 3 cm. [5]
The leaves have smooth edges, no visible veining, and a rounded shape. Young branchlets are curved and green. The flowers are tiny (3–5 mm in diameter), greenish-yellow, and lightly scented. When the yellow fruit has matured, it is rounded with about a 6-mm diameter. The ripe fruit has green interior flesh and one sticky seed. [6]
Ileostylus micranthus is listed as endemic to Norfolk Island with a status of vulnerability under The Environment Protection and Biodiversity Conservation Act 1999. [7] There are only 13 records of Ileostylus on Norfolk Island, with a larger abundance in New Zealand. Ileostylus micranthus can be found throughout the North Island, South Island and Stewart Island. [8]
Ileostylus micranthus arrived in New Zealand in the 1930s presuming it was unaided. [9] From the 1930s onwards the distribution has increased throughout all the main islands of New Zealand. [9] Ileostylus micranthus can be founded in locations that include the Northland Podocarpus totara forests, the Rotorua/Taupō area of the Taupō Volcanic Zone's regenerating scrub and forest, as well as the grey-scrub communities of Marlborough-Kaikōura, Banks Peninsula, Central Otago (the Lake District), and Dunedin. [10] Ileostylus is also frequently connected to Cook Strait's coastal forests, saline marches, and portions of Nelson and Westland.
Ileostylus micranthus occurs mostly in the lowland districts in the North Island, South Island and Stewart Island. The distribution of this species indicates that it prefers lowland environments and that there is no clear national correlation between it and any host.
Ileostylus micranthus compared to other parasitizing mistletoes within New Zealand is newly introduced. The variability of spatial and temporal host availability since its arrival has appeared to have the most favored host generalization. There are two modes of important evolutionary variety for parasites which are co-speciation and host-switching. [10] Ileostylus micranthus appears to have no host specialization due to having records of parasitizing taxa over 209 species including 92 exotic species and three species that are restricted to Norfolk Island. [11]
Ileostylus micranthus has unique physiological characteristics and morphological structures that assist them to develop connections with its host plants. Water, organic acids, ions, sugars, minerals and amino acids can be easily transported through the connections made by the vascular connection points. The nutrients required for attachment and the growth of the first photosynthetic structures are supplied by maternal reserves when an Ileostylus micranthus seed is dispersed by birds to the host branch. Ileostylus micranthus has viscous seeds meaning that it has a thick residue surrounding the exterior of the seed. [12] This is an adaptation to adhere to the host species and the parasite then needs to establish a connection with the host in order to continue functioning. Once the parasite has become established, the hypocotyl straightens and pulls the two cotyledons out of the endosperm. The first pair of true leaves usually develop around four weeks after the initial pair of small green cotyledons, which function as leaves. [4]
Fully developed Ileostylus micranthus plants have a high use of water and nutrients (N and P), wide stomata and low stomatal density. [13] Low stomatal density impacts and influences the plant's characteristics for plant growth which can be calculated by the stomata number per unit leaf area. [14] Ileostylus micranthus accumulates the host plant species’ nutrients (C, K, N, P, Ca, and Mg) into their own tissues by making them soluble. This process takes the host plant species’ reserves of non-structural carbohydrates, negatively impacting the efficiency of the host plant processes.
Silvereyes, bellbirds, and tui are the three most significant avian dispersers of the Ileostylus micranthu seeds. [4] The fruits are swallowed whole, and the seeds later became defecated in a germinal state. These birds tend to frequent plants for only 1-2 minutes, eating a few mistletoe fruits each time. Seeds fail to germinate unless the fruit exterior, or exocarp, is removed, either manually or by passing through the gut of a bird. The only method of exocarp removal that is successful in the field is bird dispersal, even though hand removal of the exocarp can result in a germination rate that was equal to or higher than that of bird removal. [4]
If the fruit of the Ileostylus micranthus has not been consumed by avian dispersers, the fruit will overripen and fall off the fruit stalk and rot, negatively impacting the germination and success of the seed. [15] Ileostylus micranthus have unspecialized flowers which means that native and or introduced insect species can pollinate. [10] Flowering occurs between September to December and Fruiting occurs between the months of April to June. [5]
Native Loranthaceae are less prevalent than they were a century ago in many parts of New Zealand. The traditional explanation for this decline is that habitat destruction and, more recently, possum browsing is to blame. [4] Native avian species (and the self-introduced silvereye) almost entirely carry out dispersal. Introduced frugivorous birds, like blackbirds and thrushes, eat scant amounts of mistletoe fruit and cannot make up for the decline in native bird populations brought on by the arrival of mammalian predators. [4]
Fruit production is partially limited to the dispersal of the amount of bird availability. This could be related to a number of factors such as the competitive interactions being increased by the introduction of new insect species which are using resources such as honeydew for the intention of food supply. As well as the overall densities of avian dispersers to fulfil the mutual relationship that the Ileostylus micranthus creates with birds (Tui, bellbird, Silvereye and introduced birds).
Predators can impact the Ileostylus micranthus indirectly and directly. Indirectly, mammalian introduced species can negatively impact the population of seed dispersers (native and introduced birds). Ileostylus micranthus relies heavily on the seed dispersers to reach their host species and to be able to attach to the host species (removal of the exocarp).
Tui and other native bird species fluctuate in population densities, which the change in population can be a strong influence on Ileostylus micranthus success. [16] Due to impacting the rate of reproduction and survival for Ileostylus micranthus. [4] Avian seedvdispersers are facing an increase in habitat loss and non-native mammalian predators including the Norway rat ( Rattus norvegicus), Polynesian rat ( Rattus exulans) and the Ship rat ( Rattus). Other species that are predators include the Brushtail possums ( Trichosurus vulpecula), Cats ( Felis catus), Mustlelids and Mice (Mus musculus) which all prey on the dependable Ileostylus micranthus seed dispersers. [17]
The direct effect of these mammalian introduced species is the predation of the Ileostylus micranthus flowers and seeds, These predators impact the reproduction and survival rate due to the disturbance of the germination process (avian dispersers are unable to digest the seeds to remove the exocarp for germination). To be able to conserve and maintain the Ileostylus micranthus population, measures need to be implemented to ensure that the avian seed dispersers maintain or increase population densities to increase the survival and reproductive rate of Ileostylus micranthus.
Mistletoe is the common name for obligate hemiparasitic plants in the order Santalales. They are attached to their host tree or shrub by a structure called the haustorium, through which they extract water and nutrients from the host plant.
A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance and nutritional composition of fruits. Frugivores can benefit or hinder fruit-producing plants by either dispersing or destroying their seeds through digestion. When both the fruit-producing plant and the frugivore benefit by fruit-eating behavior the interaction is a form of mutualism.
Coprosma robusta, commonly known as karamū, is a flowering plant in the family Rubiaceae that is endemic to New Zealand. It can survive in many climates, but is most commonly found in coastal areas, lowland forests, or shrublands. Karamū can grow to be around 6 meters tall, and grow leaves up to 12 centimeters long. Karamū is used for a variety of purposes in human culture. The fruit that karamū produces can be eaten, and the shoots of karamū are sometimes used for medical purposes.
In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, such as the wind, and living (biotic) vectors such as birds. Seeds can be dispersed away from the parent plant individually or collectively, as well as dispersed in both space and time. The patterns of seed dispersal are determined in large part by the dispersal mechanism and this has important implications for the demographic and genetic structure of plant populations, as well as migration patterns and species interactions. There are five main modes of seed dispersal: gravity, wind, ballistic, water, and by animals. Some plants are serotinous and only disperse their seeds in response to an environmental stimulus. These modes are typically inferred based on adaptations, such as wings or fleshy fruit. However, this simplified view may ignore complexity in dispersal. Plants can disperse via modes without possessing the typical associated adaptations and plant traits may be multifunctional.
The pale-billed flowerpecker or Tickell's flowerpecker is a tiny bird that feeds on nectar and berries, found in India, Sri Lanka, Bangladesh and western Myanmar. The bird is common especially in urban gardens with berry bearing trees. They have a rapid chipping call and the pinkish curved beak separates it from other species in the region.
Fuchsia excorticata, commonly known as tree fuchsia, New Zealand fuchsia and by its Māori name kōtukutuku, is a New Zealand native tree belonging to the family Onagraceae. It is commonly found throughout New Zealand and as far south as the Auckland Islands. It grows from sea level up to about 1,000 m (3,300 ft), particularly alongside creeks and rivers. It is easily recognised in its native environment by the characteristic appearance of its bark, which peels spontaneously, hanging in red papery strips to show a pale bark underneath. Its scientific name, excorticata, reflects this distinctive property.
Phoradendron is a genus of mistletoe, native to warm temperate and tropical regions of the Americas. The center of diversity is the Amazon rainforest. Phoradendron is the largest genus of mistletoe in the Americas, and possibly the largest genus of mistletoes in the world. Traditionally, the genus has been placed in the family Viscaceae, but recent genetic research acknowledged by the Angiosperm Phylogeny Group shows this family to be correctly placed within a larger circumscription of the sandalwood family, Santalaceae.
The mistletoebird, also known as the mistletoe flowerpecker, is a species of flowerpecker native to most of Australia and also to the eastern Maluku Islands of Indonesia in the Arafura Sea between Australia and New Guinea. The mistletoebird eats mainly the berries of the parasitic mistletoe and is a vector for the spread of the mistletoe's seeds through its digestive system.
Tristerix is a genus of mistletoe in the family Loranthaceae, native to the Andes, ranging from Colombia and Ecuador to Chile and Argentina. They are woody perennials usually occurring as aerial parasites, are pollinated by hummingbirds and flowerpiercers, with seed-dispersal generally by birds but occasionally by mammals (Dromiciops). The genus is distinguished from other New World Loranthaceae by its simple, terminal, racemose inflorescences, together with its of 4- or 5-merous flowers, versatile anthers, and the presence of endosperm. Further differences include fused cotyledons and the absence of epicortical roots.
Amyema miquelii, also known as box mistletoe, is a species of flowering plant, an epiphytic hemiparasitic plant of the family Loranthaceae, found attached to several species of Australian eucalypt and occasionally on some species of Acacia. It is the most widespread of the Australian Mistletoes, occurring mainly to the west of the Great Dividing Range. It has shiny leaves and red flowers arranged in groups of 3. It is distinguished from the similar Amyema pendula through the individual stalks of the flowers.
Peraxilla tetrapetala, or red mistletoe, is a parasitic plant in the family Loranthaceae, endemic to New Zealand and found on both the North and South Islands. The Māori names for the plant are pikirangi, pirirangi and roeroe.
Myrsine australis, commonly known as māpou, red matipo, tīpau, and mataira is a species of shrub within the family Myrsinaceae. It is endemic to New Zealand, found throughout both the mainland and offshore islands.
Amyema quandang is a species of hemi-parasitic shrub which is widespread throughout the mainland of Australia, especially arid inland regions, sometimes referred to as the grey mistletoe.
Phoradendron tomentosum, the leafy mistletoe, hairy mistletoe or Christmas mistletoe, is a plant parasite. It is characterized by its larger leaves and smaller berries than dwarf mistletoe. Leafy mistletoe seldom kill but they do rob their hosts of moisture and some minerals, causing stress during drought and reducing crop productions on fruit and nut trees. Leafy mistletoe has the ability to photosynthesize on its own but it relies on other plants in order to obtain its nutrients. It attaches itself to a tree and then grows haustoria, in order to get the food and water it needs.
Amyema preissii, commonly known as wireleaf mistletoe, is a species of mistletoe, an epiphytic, hemiparasitic plant of the family Loranthaceae. It is native to Australia where it has been recorded from all mainland states. The flowers are red and up to 26 mm long. The fruits are white or pink, globose and 8–10 mm in diameter. Its habitat is sclerophyll forest and woodland where it is often found on wattles. On Victoria's Bellarine Peninsula its hosts include coast wirilda, golden wattle and drooping sheoak. Its sticky seeds are eaten and dispersed by mistletoebirds.
Lysiana exocarpi, commonly known as harlequin mistletoe, is a species of hemiparasitic shrub, endemic to Australia. It is in the Gondwanan family Loranthaceae and is probably the most derived genus of that family with 12 pairs of chromosomes. The Loranthaceae is the most diverse family in the mistletoe group with over 900 species worldwide and including the best known species in Australia. Mistletoes are notable for their relationships with other species. In an early reference to the group in Australia Allan Cunningham explorer and first Director of the Royal Botanic Gardens, Sydney, wrote in 1817: "The Bastard Box is frequently much encumbered with the twining adhering Loranthus aurantiacus which 'Scorning the soil, aloft she springs, Shakes her red plumes and claps her golden wings'."
Victoria Forest Park, is situated on the West Coast of the South Island of New Zealand. At 2,069 square kilometres (799 sq mi) it is New Zealand's largest forest park. The park is administered by the Department of Conservation (DOC).
Psittacanthus schiedeanus G.Don is a species of Neotropical mistletoe in the family Loranthaceae, which is native to Panamá, Costa Rica, Honduras and Mexico.
Peraxilla colensoi, the scarlet mistletoe, is a shrubby parasitic plant composed of broad, leathery leaves that grow up to 8 cm long and have a red edge. The common name is derived from the scarlet petals of the plant that bloom every October to January. These mistletoes are parasitic plants whose seeds attach themselves to host plants. The most common host for these plants is the silver beech. The plant can grow up to 3 meters tall and are often located in low altitudes throughout the North and South Islands of New Zealand.
Amyema miraculosa, also known as the fleshy mistletoe and the round-leaf mistletoe, is an Australian native mistletoe found in all states except Tasmania. It is a woody, hemiparasitic plant, in the Loranthaceae family. Being hemiparasitic, it draws water and minerals from its host, however it photosynthesises to manufacture its own supply of carbohydrates.
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