Phyllocladus
Encyclopedia
Phyllocladus is a small genus
of conifers
, now usually treated in the family
Podocarpaceae
. They are morphologically
very distinct from the other genera in that family, and some botanists treat them in a family of their own, the Phyllocladaceae. One molecular phylogenetic analysis found Phyllocladus to be sister to Podocarpus sensu stricto. Another was equivocal on its position
relative to Podocarpaceae s.s..
Phyllocladus is mainly a southern hemisphere
genus, occurring
in New Zealand
, Tasmania
and Malesia
, where one species crosses a short way north of the equator
in the Philippines
.
The five species are genetically
distinct, and probably arose
between 5 and 7 million years ago.
s, reaching 10-30 m tall, or sometimes small shrub
s. The main structural shoots are green for 2-3 years, then turn brown as the bark thickens. The leaves are sparse, tiny, scale-like, 2-3 mm long, and only green (photosynthetic) for a short time, soon turning brown. Most photosynthesis
is performed by highly modified, leaf-like short shoots called phylloclade
s; these develop in the axils of the scale leaves, and are simple or compound (depending on species). Simple phylloclades are rhombic, 2-5 cm long, and compound phylloclades are up to 20 cm long and subdivided into 5-15 'leaflet'-like phylloclades 1-3 cm long. The seed cones
are berry
-like, similar to those of several other Podocarpaceae genera, notably Halocarpus
and Prumnopitys
, with a fleshy white aril
; the seeds are dispersed by bird
s, which digest the soft fleshy aril as they pass the hard seeds in their droppings.
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 conifers
Pinophyta
The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...
, now usually treated in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Podocarpaceae
Podocarpaceae
Podocarpaceae is a large family of mainly Southern Hemisphere conifers, comprising about 156 species of evergreen trees and shrubs. It contains 19 genera if Phyllocladus is included and if Manoao and Sundacarpus are recognized....
. They are morphologically
Plant morphology
Plant morphology or phytomorphology is the study of the physical form and external structure of plants. This is usually considered distinct from plant anatomy, which is the study of the internal structure of plants, especially at the microscopic level...
very distinct from the other genera in that family, and some botanists treat them in a family of their own, the Phyllocladaceae. One molecular phylogenetic analysis found Phyllocladus to be sister to Podocarpus sensu stricto. Another was equivocal on its position
Phylogenetic tree
A phylogenetic tree or evolutionary tree is a branching diagram or "tree" showing the inferred evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical and/or genetic characteristics...
relative to Podocarpaceae s.s..
Phyllocladus is mainly a southern hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
genus, occurring
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...
in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
and Malesia
Malesia
Malesia is a biogeographical region straddling the boundaries of the Indomalaya ecozone and Australasia ecozone, and also a phytogeographical floristic region in the Paleotropical Kingdom.-Floristic province:...
, where one species crosses a short way north of the equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
.
The five species are genetically
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
distinct, and probably arose
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...
between 5 and 7 million years ago.
Description
They are small to medium-size treeTree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s, reaching 10-30 m tall, or sometimes small shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s. The main structural shoots are green for 2-3 years, then turn brown as the bark thickens. The leaves are sparse, tiny, scale-like, 2-3 mm long, and only green (photosynthetic) for a short time, soon turning brown. Most photosynthesis
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
is performed by highly modified, leaf-like short shoots called phylloclade
Phylloclade
Phylloclades are cladodes, i.e., flattened, photosynthetic shoots, which are modified branches. Phylloclades are cladodes that greatly resemble or perform the function of leaves, as in Butcher's broom as well as Asparagus and Phyllanthus species. Phyllocladus, a genus of conifer, is named after...
s; these develop in the axils of the scale leaves, and are simple or compound (depending on species). Simple phylloclades are rhombic, 2-5 cm long, and compound phylloclades are up to 20 cm long and subdivided into 5-15 'leaflet'-like phylloclades 1-3 cm long. The seed cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
are berry
Berry
The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....
-like, similar to those of several other Podocarpaceae genera, notably Halocarpus
Halocarpus
Halocarpus is a genus of conifers belonging to the Podocarp family Podocarpaceae. The genus includes three closely related species of evergreen trees and shrubs, all endemic to New Zealand. - External links :* At: At:...
and Prumnopitys
Prumnopitys
Prumnopitys is a genus of conifers belonging to the podocarp family Podocarpaceae. The eight recognised species of Prumnopitys are densely-branched, dioecious evergreen trees up to 40 metres in height. The leaves are similar to those of the yew, strap-shaped, 1-4 cm long and 2-3 mm broad, with a...
, with a fleshy white aril
Aril
An aril is any specialized outgrowth from the funiculus that covers or is attached to the seed. It is sometimes applied to any appendage or thickening of the seed coat in flowering plants, such as the edible parts of the mangosteen and pomegranate fruit, the mace of the nutmeg seed, or the...
; the seeds are dispersed by bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, which digest the soft fleshy aril as they pass the hard seeds in their droppings.
Species
- Phyllocladus alpinusPhyllocladus alpinusPhyllocladus alpinus is a species of conifer in the Podocarpaceae family. It is found only in New Zealand. The form of this plant ranges from a shrub to a small tree of up to seven metres in height. An example occurrence of P. alpinus is within the understory of beech/podocarp forests in the north...
(P. trichomanoides var. alpinus) - Mountain Toatoa (New ZealandNew ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
) - Phyllocladus aspleniifoliusPhyllocladus aspleniifoliusPhyllocladus aspleniifolius is an endemic gymnosperm of Tasmania, Australia. It is found in rainforest as a dominant, in eucalypt forest as an understorey species, and occurs occasionally as a shrub in alpine vegetation...
- Celery-top-pine (TasmaniaTasmaniaTasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
) - Phyllocladus hypophyllusPhyllocladus hypophyllusPhyllocladus hypophyllus is a species of conifer in the Podocarpaceae family.It is found in Brunei, Indonesia, Malaysia, Philippines, and Papua New Guinea.-References:* Conifer Specialist Group 1998. . Downloaded on 10 July 2007....
- Malesian Celery-pine (New GuineaNew GuineaNew Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
to BorneoBorneoBorneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
& PhilippinesPhilippinesThe Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
) - Phyllocladus toatoaPhyllocladus toatoaPhyllocladus toatoa is a species of conifer in the Podocarpaceae family.It is found only in New Zealand.-References:* Conifer Specialist Group 1998. . Downloaded on 10 July 2007....
- Toatoa (New ZealandNew ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
) - Phyllocladus trichomanoidesPhyllocladus trichomanoidesPhyllocladus trichomanoides is a coniferous tree native to New Zealand.Tanekaha is a medium-sized forest tree growing up to 20 m in height and 1 m trunk diameter. The main structural shoots are green for 2–3 years, then turn brown as the bark thickens...
- Tanekaha (New ZealandNew ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
)
Sources
- Quinn, C. J. & Price, R. A. 2003. Phylogeny of the Southern Hemisphere Conifers. Proc. Fourth International Conifer Conference: 129-136.
External links
- Gymnosperm Database - Phyllocladus