Pinophyta | Article about Pinophyta by The Free Dictionary Pinophyta | Article about Pinophyta by The Free Dictionary Related to Pinophyta: Coniferophyta Pinophyta (pī'nŏf`ətə), division of the plant kingdom consisting of those organisms commonly called gymnosperms. The gymnosperms, a group that includes the pine, have stems, roots and leaves, and vascular, or conducting, tissue (xylem and phloem). In these plants the ovules, or young seeds, are exposed to the air at the time of pollination, hence the term gymnosperm, meaning naked seed. Pollination is always by wind. Because the seed-bearing structures of many gymnosperms are organized into a cone, or strobilus, these plants have been called conifers conifer [Lat.,=cone-bearing], tree or shrub of the order Coniferales, e.g., the pine, monkey-puzzle tree, cypress, and sequoia. Most conifers bear cones and most are evergreens, though a few, such as the larch, are deciduous. ..... Click the link for more information.

; because the leaves of many species are perennial, they have also been called evergreens. Class Cycadopsida The class Cycadopsida, or cycads, are only the small evolutionary vestige of a large and varied group of plants that flourished in late Paleozoic and Mesozoic time. The only order of living cycads, the Cycadales, is dioecious, i.e., male and female cones are borne on separate plants. Although cycads resemble the palms in form and usually have erect stems that reach 50 ft (15 m) in height, they have very little wood; rather, they are supported largely by a hard outer layer of the stem. They have large, fernlike leaves and produce seeds in terminal cones. In their reproduction, pollen grains, or microspores, are transported by wind to the female spore case, or megasporangium. Within the microspore wall, motile flagellated sperms are produced, unlike the nonmotile sperms of the higher gymnosperms. Class Pinopsida The class Pinopsida is characterized by generally small, always simple leaves and by the active secondary growth of stem and root.

Many members of this group flourished from Lower Carboniferous times to the Permian age. Plants of the order Pinales (conifers) occur in the Northern Hemisphere; a few species occur within the tropics at sea level. Conifers are the most numerous of living gymnosperms and form large and relatively pure forests. Common examples of conifers are the pines, firs, spruces, redwoods, cedars, junipers, hemlocks, and larches. The wood of conifers is used extensively for construction of all kinds. It has no vessels and thus differs from the wood of angiosperm trees. Although conifers are called softwoods and angiosperm trees hardwoods, the wood of some pines is much harder than that of some angiosperms. Most conifers are monoecious, i.e., the male and female cones occur on the same tree. The microspores, or pollen grains, are produced in such vast abundance that clouds of pollen, carried on the wind, have settled on ships far at sea.

In plants of the order Taxales ( yews yew, name for evergreen trees or shrubs of the genus Taxus, somewhat similar to hemlock but bearing red berrylike fruits instead of true cones. Of somber appearance, with dark green leaves, the yew since antiquity has been associated with death and funeral rites. ..... Click the link for more information. ) the seeds, produced individually on short shoots, are surrounded by a conspicuous, fleshy covering. Other Classes Gymnosperms Gymnosperms Evolutionary development of the seed Seeds consist of an embryo already packaged within the seed, and nutritive tissue surrounded by a protective coat. 1. A seed contains a well-developed multicellular young plant with embryonic root, stem, and leaves already formed, whereas a plant spore is a single cell. 2. The parent plant protects and supports the young plant in the seed during its development; spores do not receive such attention. 3. A seed contains a food supply. After germination, in which the young plant begins to grow and establish itself as an independent plant, it is nourished by food stored in the seed until it becomes self-sufficient.

Because a spore is a single cell, minimal food reserves exist to sustain the plant that develops from a germinating spore. 4. The seed is protected by a multicellular coat. Seeds (and spores) can survive for extended periods of time at reduced rates of metabolism and then germinate when conditions become favorable. 5. Seeds and seed plants have been intimately connected with the development of human civilization. From prehistoric times, early humans collected and used seeds for food. The food supply stored in seeds contains proteins, oils, carbohydrates, and vitamins that are nourishing for humans as well as for germinating plants. 6. Because seeds are easy to store, provided they are kept dry, humans could collect seeds during times of plenty, and save them for times of need. Few other foods can be stored as conveniently or for as long as seeds. 7. The elimination of the necessity of water to transport the sperm grom the microgametophyte to the megagametophyte for fertilization to occur. 8. This development made it possible for seed plants to complete their life cycles in relatively dry environments, compared to those of non-seed-producing vascular plants.

Seed production is an adaptation of great significance for the survival and dispersal of plants. In fact, this was part of the competititve advantage that allowed the gymnosperms to supercede the other vascular plants as the dominant type of vegetation on land. Only the later evolution of flower and fruit allowed another group of seed plants (the angiosperms) to displace the gymnosperms from their preeminent position. Gymnosperms are seed-bearing plants that lack the combination of specialized features that characterize the flowering plants. The name gymnosperm, means naked seed. (e.g. gymnasium); that is, the seeds are not enclosed within fruits. Gymnosperms, then, are all fruitless seed plants. And they are made up of a heterogeneous group of plants characterized by the production of naked seeds. Estimates form fossil records indicate that gymnosperms must have evolved approximately 300 million years ago from non-seed producingï¿½ ancestors of the extinct division of Progymnospermophyta, which were fern-like in appearance.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ ï¿½ 1.ï¿½ They lack the folded, marginally-sealed carpels that characterize the flowering plants. 2.ï¿½ The pollen-receptive structures are the ovules rather than the stigmatic portion of the carpels. ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ 3.ï¿½ Most gymnosperms lack vessels in their xylem (unlike flowering plants which have both vessels and tracheids), except for the gnetophytes, which have vessels. Considering the relatively small number of living gymnosperms (about 720 species in 65 genera), they are remarkably diverse in their reproductive structures and leaf types. Gymnosperms, like angiosperms (the flowering plants), differ from seedless plants (like mosses and ferns) in not requiring water for sperm to swim in to reach the egg.

This means that the movement of pollen (male gamete) to ovule (female gamete) in seed plants relies on airborne transport, not water transport. Consequently, most gymnosperms produce huge amounts of pollen. ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ 1.ï¿½ In gymnosperms, pollen is found (located) in stamen-like structures called strobili (various types of cones).ï¿½ (strobilus = singular). ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ 2.ï¿½ The pollen grains of Pinus and several other genera have bladder-like wings. ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ 3.ï¿½ Each male of a pine tree cone annually releases an estimated 1-2 million pollen grains.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ 4.ï¿½ Pollination in gymnosperms involves a pollination droplet that protrudes from the micropyle when pollen grains are being shed. The droplet provides a large, sticky surface that catches the normally wind-borne pollen grains of gymnosperms so that the ovule is more likely to be fertilized. After pollination the droplet evaporates and contracts, carrying the pollen grains into the pollen chamber and into contact with the ovule. The most dramatic differences between gymnosperms and other plants involve pollen and seeds and the organs that bear them. These features differ significantly from those of comparable organs of flowering plants. Strobilus (cone) ï¿½ the reproductive structure in gymnosperms. In conifers, this consists of an ovoid, cylindrical, or spherical cluster of sporophylls (cone scales) arranged around a central axis. The place where seeds of gymnosperms are produced; essentially, an evolutionarily modified branch. There are 4 major divisions of plants within the gymnosperms: 1.

Ginkgophyta (Ginkgo: maidenhair tree), 2. Cycadophyta (Cycads), 4. Pinophyta or Coniferophyta (the conifers). A. Ginkgo 1. Ginkgo biloba, or maidenhair fern because of the resemblance of its fan-shaped leaves to those of maidenhair ferns, is the only living representative of the division. It is the oldest known genus (and species) of living trees. Fossil ginkgo leaves and wood have been discovered that date back 200 million years, and are nearly identical to those of the modern-day ginkgo. 2. It is exclusively dioecious and deciduous. 3. It has distinctive fan-shaped leaves with dichotomous venation; it is deciduous. Both attributes resemble angiosperms. However, the fleshy seed coat of Ginkgo can easily be mistaken for a fruit. 4.

The seeds of Ginkgo include a massive integument (outer coating of an ovule; later becoming testa of a seed) that consists of a fleshy outer layer, a hard, stony middle layer, and an inner layer that is dry and papery. a. Mature seeds have the size and appearance of small plums, but the fleshy integument has a nauseating odor (like a vomitorium) and irritates the skin of some people. (Nevertheless, pickled Ginkgo seeds are a delicacy in some parts of Asia ). b. Paired ovule, not in cones, produced at the tips of short branches on the female trees. 5. They are a popular cultivated tree, but it is apparently extinct in nature. a. All living Ginkgo trees are descendants of plants that were grown in temple gardens of China Japan . b. Most of the genetic diversity of Ginkgo has probably been lost in cultivation, because most nurseries propagate only cuttings of microsporangiate trees (male trees) to avoid the stinky and messy seeds. c. Introduced to the American continent and Europe as an ornamental tree, a fact credited with saving it from extinction. d.

Part of its popularity has to do with its putative resistance to many types of air pollution common around industrial sites. B. Cycads (from the Greek kykas, ï¿½a palmï¿½). Cycadophyta 1. Very important plant group during the Triassic period, which occurred aprox. 250 million years ago, and is sometimes referred to as ï¿½the age of the cycadsï¿½. 2. In the few surviving cycads, there are about 10 genera and 100 spp., distributed primarily in the tropical and subtropical regions of the world. a. There only 2 species of cycads native to the U.S. ï¿½ both are in the genus Zamia, and neither lives in the wild outside Florida . 3. All spp. of cycads are dioecious, producing microsporangial (male) cones and ovulate (female) cones at the terminal end of the trunk (which is unbranched). 4. Cycads have palm-like leaves that bear no resemblance to leaves of other living gymnosperms. a. Under favorable conditions, cycads usually produce one crown of leaves each year. b.

The roots of some cycads may grow at the surface of the soil and contain nitrogen-fixing cyanobacteria. c. Very slow growing; in one case, a plant reached the height of 6ï¿½ only after 1,000 years of growth. 5. Seeds of cycads are like those of Ginkgo, except the inner layer is soft instead of papery. 6. Whereas Ginkgo has rather loose microstrobili and single-seeded stalks, and deciduous simple leaves, cycads have large strobili and persistent palm-like leaves. C.ï¿½ Conifers (Coniferophyta or Pinophyta) 1. The informal name of the group, conifers, signifies plants that bear cones, even though other members of the gymnosperms also include cone-bearing species. 2. Members of the genus Pinus, considered typical for the Pinophyta, fare the most abundant trees in the Northern Hemsisphere ; many of the species in conifer forests are pines. 3. In Nevada , genera that are included within Pinophyta are Pinus (pine), Picea (spruce).

Pseudotsuga (Douglas-fir),a nd Abies (fir) from the Pianceae; Juniperus (juniper) and Calocedrus (incense-cedar) from the Cupressaceae (cypress family). 4. Pines a. The genus Pinus, by far the largest genus within the conifers, consists of about 100 spp. b. Pines actually have 2 kinds of leaves. The more obvious leaf is the pine needle, a simple leaf, which is produced singly or clustered in definite numbers, called fascicles, of generally 2 to 5 needles c. A fascicle always forms a cylinder or collar when the leaves are held together. (They are actually short shoots that are surrounded at their base by small, nonphotosynthetic, scalelike leaves that usually fall off after 1 year of growth). d. Needle-bearing fascicles are shed a few at a time, usually every 2-5 years, so that any pine tree, while appearing evergreen, has a complete change of leaves every 5 years or so. (Bristlecone pines are an exception: their needles last an average of 25-30 years).

All genera of Pinophyta are evergreen except the larches, bald cypress (Taxodium distichum), and the dawn redwood (Metasequoia glyptostroboides) which are deciduous. e. Pines produce 2 kinds of cones (strobili). 1. Male cones, usually 1 cm or less in length, are smaller than female cones, and generally occur in dense clusters on the ends of the lower branches each spring. 2. The more familiar female cones, which are on the tree year-round, are usually located on the upper branches on the pine tree, and bear seeds after sexual reproduction has occurred. Female cones vary considerably in size among pine species: about 2ï¿½ in bristlecone pine to over 2ï¿½ in sugar pine. f. So, pines are monoecious; male and female cones are produced separately, but on the same tree. g. Unlike other gymnosperms, in which pollination, fertilization, and seed maturation occur within the same year, the pines have an extended reproductive cycle of 14-20 months.

(The period elapsed between the appearance of the ovulate cone and the maturation of pine seeds in those cones. Fertilization takes place about 1 year after pollination, and seed maturation takes several additional months). Some seeds are shed as soon as they mature, whereas others remain within the female cones for weeks, months, or even years before being shed. h. Other members of Pinophyta in the Northern Hemisphere also have narrow leaves that have a small point at the tip, but they are not held together in a fascicle like those in Pinus. These include yews (Taxus), fir (Abies), larches (Larix), redwoodsï¿½ (Sequoia sempervirens), and spruces (Picea). 5. Leaves of Cypresses (Cupresses) and juniper (Juniperus) are scalelike at maturity. 6. Diversity within Pinophyta is reflected in the wide variety of reproductive structures and variations of the reproductive cycle. a. Pines, firs, Douglas-firs, spruces, etc bear cones (stobili) of different sizes and shapes. b.

Seed cones may be absent entirely, as in the yews, which bears seeds surrounded by a fleshy, cuplike covering that is an outgrowth from the base of the seed. The seed covering is red and attracts birds, which eat them and disperse the seeds. c. Junipers have stobili, fleshy cones, with a berry-like appearance. The fleshy scales are fused together and completely envelop the seed. Cones at maturity may be orange, red, brown, purple, or black, depending on the species. Birds eat the cones and swallow the seeds, which are then dispersed in their droppings. Pinaceae is monoecious; Cupressaceae is monoecious or dioecious. 7. Vegetative features of Pinaceae are important in their ecological success. a. Most species have a strongly dominant central axis and grow with a characteristic spire-like habit, which helps to maximize photosynthesis when the solar angel is low, and enables the tree to shed snow. b. The stems, leaves, and cones have resin ducts that contain substances that seal damaged surfaces and are somewhat insect-resistant. c.

The needle-like leaves have sunken stomata and a thick epidermis to retard water loss. d. Members of Pinaceae have small, ephemeral pollen cones and small to large woody ovulate (seed) cones. i. A pollen cone consists of a central axis and numerous small, flat, microsporophylls, each with two microsporangia on its lower surface. Scales of pollen cones remain small and soft. They are usually produced in clusters near the tips of lower branches (ovulate cones are produced either singly or in pairs on the younger branches). Within the same species the mature pollen cones are always small, commonly less that 1ï¿½ long, whereas the ovulate cones are large, measuring up to 2ï¿½ long in the sugar pine. The pollen cone develops during early spring. ii. Ovulate cones are more complicated. The cone has a woody axis to which are attached spirally arranged cone scales (ovuliferous scales), each of which is subtended by a scale-like bract. Two ovules are attached to the upper surface of each scale.

These mature in most members of the family as winged seeds that break free from the cone scale at the time the woody cone scales are dry and separate. iii. The transfer of pollen from the pollen cone to the ovulate cone is called pollination. After the release of pollen grains, the pollen cone dries up and falls off. A pine tree produces a prodigious amount of pollen, most of which never lands on the female cones, but instead settles on any stationary object as a fine yellow powder. iv. Ovulate cones usually remain on the tree for about 2 years. v. Pine seeds are usually dispersed during autumn when the scales of the ovulate cones separate. vi. Cones of some pines so not open so gracefully or easily: these cones often require a fire to cause them to open and release their seeds (serotiny). The cones of some pines explode like popcorn when heated. e. Economically the Pinaceae is the most important gymnosperm family. Many species are important lumber trees. In much of the world the Pinaceae is the principal source of wood pulp for paper (white spruce, Picea glauca).

Some are economically valuable as sources of resins (sticky, aromatic substance in resin canals of conifers), turpentine (volatile liquid used in solvents as paint thinner and varnishes), rosin (used in the manufacture of floor waxes and paper coating; on bows of stringed instruments, and baseball pitchers use it for better grip on the ball(, amber (hard, yellowish to brown translucent substance, is fossilized resin, used chiefly in jewelry),and other extracts. i. Douglas fir and Hemlock/Douglas fir mix used in construction. Strong wood, relatively free of knots as a result of rapid growth with less branching than other conifers. ii. Redwoods (Sequoia sempervirens) are prized for their wood, which contains substances that inhibit the growth of fungi and bacteria. iii. Spruce wood is important to the music industry. Tracheids of spruces have spiral thickenings on the inner walls, which apparently give the wood a resonance that makes it ideal for use as soundboards in violins and guitars. 1. This group includes some of the most distinctive, and bizarre, seed plants. 2.

There are 3 clearly defined, morphologically dissimilar genera of theseï¿½ gymnosperms: Ephedra (40 spp.), Gnetum (30 spp.), and Welwitschia (1 sp). 3. One feature they all share, in addition to being gymnosperms, is the presence of vessel elements in their wood, a cell type absent in other gymnosperms. 4. Ephedra (Mormon tea, ma huang, joint fir ï¿½ the first two names referring to its use as a stimulating or medicinal tea. Ma huang is an Asian species, E. sinica, which contains chemicals that are similar to those of human neurotransmitters, like ephedrine, a drug used for the relief of allergic symptoms because of its ability to constrict blood vessels. It is also a heart stimulant and hass been sold over-the-counter in weight-c0ntrol medications and herbal energy-boosters. (In 1996 at least 15 deaths were attributed to chronic use or overdose of products containing Ephedra, as were the two athletes who recently died).

Joint fir refers to the leafless appearance of Ephedra stems, which resemble the jointed stems of Equisetum, horsetail.) a. Ephedra is not actually leafless; its leaves are small and lose their photosynthetic capability as they mature. Most photosynthesis in Ephedra occurs in green stems. b. They are restricted to desert or semi-desert habitats, the arid southwest in the U.S. 5. Ephedra are either monoecious or dioecious. 6. Most spp of Gnetum are tropical and dioecious, either climbing vines of trees, all with broad leaves similar to those of woody dicots. 7. Welwitschia mirabilis is the sole living representative of its genus and looks more like something out of a science fiction movie than a real plant. c. This slow-growing species is confined to the Namib Desert Africa . d. Most of its moisture is derived from fog that rolls in from the ocean at night. e. The woody stem is concave and bark-encrusted, maybe as much as 1.5 meters in diameter, and connected to a very large taproot. Much of the stem is underground. f.

Mature plants have a pair of strap-shaped leaves (up to 9ï¿½ long), which persist throughout the life of the plant. Each leaf has a meristem at its base, which constantly replaces tissue that is lost at its drier, aging tip. g. As the plant ages, the leaves periodically split lengthwise giving the plant the appearance of having many leaves. h. Welwitschia is dioecious, producing male and female strobili in different plants, originating from the axils (angle formed between upper side of petiole and stem) of leaves. i. Growth of these plants is unusually slow die to the dry environment. Gnetophytes are the most distinctive of gymnosperms because of their similarities with angiosperms. a. They have flower-like compound strobili. b. They have vessels in secondary xylem. c. They have double fertilization. (However, this double fertilization does not result in the formation of endosperm. Instead, the diploid cell from fertilization by the second sperm disintegrates).

Conifers | Tentative Plant Scientist Tentative Plant Scientist A gardener's exploration into the world of botany Menu Plant Divisions: Conifers What makes conifers different to other plants? All conifers, from pine trees to leylandii to yew trees, are within the Division Pinophyta (aka Coniferophyta). The number of species in this division is quite small, approximately 570 (although some estimates are higher), compared to 12,000 in the Bryophyta Division (mosses) or several hundred thousand in the Magnoliophyta Division (flowering plants). However, conifers make up a significant proportion of plant matter – about 34% of the total forest area – most of this is in the Northern hemisphere. All conifers are woody, either shrubs or trees, and they are largely well adapted to cold conditions and acid soils. Most are evergreen; exceptions include the larch (Larix), two species of Cypress (Taxodium distichum, Taxodium ascendens) and the Dawn Redwood (Metasequoia glyptostroboides).

Leaves are usually needle-like or scale-like, but there are a few with more strap shaped leaves. All are wind pollinated, evolving, as they did, long before brightly coloured flowers with nectar designed to attract insects. Some modern defining characteristics of conifers were not true of early conifers. For example in the Mesozoic era (252-66mya – a time when conifers were dominant and diverse) there were many deciduous conifers, some of which were not woody at all. No conifers grow in lowland tropical rainforest, salt deserts or salt marshes, however they grow just about everywhere else; on mountains and in rainforests, deserts and arctic tundra. One conifer, Retrophyllum minus, is aquatic. None are epiphytes and only one is a parasite, Parasitaxus usta (Podocarpaceae). Reproduction 3 Types of Cone on Pinus armandii Conifers do not have flowers or fruits, but, do have pollen, unlike pteridophytes which reproduce by spores (see previous blog).

Most conifers are monoecious which means they contain both male and female sexual organs on the same plant, but separately, as different cones. The male cones release pollen, the female cones receive the pollen and form seeds. As the female cone matures, it opens and the seeds are released, however this will only happen when it is dry so that the seeds will travel further not weighed down by rain. It is sometimes possible to see three different types of cone on one branch, the male, the juvenile female and the mature female containing the seeds. (The pictures below are close ups on the many individual seeds that make up the matured female cone.) Pine Cone Pinophyta Family Tree Pinophyta contains six to eight families, with a total of 65–70 genera. Originally there were 4 different orders, but three are now extinct. The extinct orders are Cordaitales, Vojnovskyales and Voltziales; the extant order is Pinales. Podocarpus and Pinus are the largest genera (but not that large) with Podocarpus having 108 species and Pinus having 109.

Pinophyta Families There is some dispute as to how the division should be divided into families, I will concentrate on the seven most distinct families Pinaceae—Pine family Pinus montezumae Pinaceae is the second largest family after Cupressaceae and is the last coniferous family to evolve, appearing approximately 150 million years ago, still a good 50 million years before flowering plants. It is mostly found in the northern hemisphere, in tropical to arctic environments. Pines have whorled branches and long needle-like leaves. The female cones are large and the male cones small. Larix and Pseudolarix are deciduous, the rest are evergreen. Whereas most conifers have two cotyledons (seed leaves), pines can have up to fifteen. Pines are aromatic and resinous – resin is a gum exuded from under the bark of the tree to seal over wounds or protect it from marauding insects as they damage the trunk. For the most part only conifers produce resin.

Larch Cones Monkey Puzzle Tree – Araucaria araucana Araucaria araucana Auracaceae is the second oldest family in Pinophyta, appearing 220mya. It contains very tall evergreen trees and is no longer native to the Northern hemisphere. The male cones are the largest of all conifer cones. This family contains both the Monkey Puzzle Tree, Araucaria araucana and the Wollemi Pine, Wollemia nobilis. Wollemi pine – Wollemia nobilis Parque Villarica – The Monkey Puzzle Forest Parque Villarica is in the Andes in Chile, it contains a spectacular section of forest at high altitude, consisting of almost entirely the Araucaria araucana and Nothofagus dombeyi – a deciduous tree, here without leaves, only white trunks. Parque Villarica Podocarpaceae—Yellow-wood family Podocarpus acutifolius This is the oldest family of conifers, appearing 240 million years ago. It contains both trees and shrubs that have a variety of different leaf types from flat to scale-like to needle-like.

Most are found in the Southern hemisphere, in the Oceana region and mostly in tropical environments. This family contains the world’s smallest conifer, Lepidothamnus fonkii which may be only 10cm tall when mature, although some can reach 60cm. Sciadopityaceae—Umbrella-pine family This family contains only one living species, Sciadopitys verticillata, known as the umbrella pine. This tree is native to Japan, a country with an especially diverse conifer population. While there is only one species, the tree has been cultivated and there are variagated, golden and columnar cultivars. The Umbrella Pine has cladodes instead of leaves, cladodes are modified stems and take the place of leaves on many cacti and on Butcher’s Broom. Japanese Umbrella Pine Sciadopitys verticillata Japanese Umbrella Pine Sciadopitys verticillata Cupressaceae—Cypress family Cupressus This is the largest conifer family and they are found throughout the world, it contains cypresses, junipers and leylandii. Trees in this family may have up to six cotyledons.

For most plants in this family the leaves start out needle like on the juvenile plants and then become scale like as the plant matures. Cephalotaxaceae—Plum-yew family Cephalotaxus harringtonia A small family with only three genera, found only in Asia and the USA. There is some debate about where it fits in the Pinophyta Division and it may eventually be combined with Taxaceae with which it has much in common. It has flat pointed leaves that sometimes curl a little and purple plum-like ‘fruits’ (see below for explanation of what these really are.) Taxaceae—Yew family Cunninghamia komshii A family of evergreen trees with flat, sometimes curving leaves. This family contains the yew tree, which has seeds covered in red, berry-like flesh to attract animals, but while these are edible, the seeds are poisonous. In autumn it is common to see patches of red liquid containing yew seeds, these are where foxes have eaten the ‘fruits’ and thrown the seeds back up to prevent poisoning.

Dawn Redwood – Metasequoia glyptostroboides Anicent Conifers Thucydia mahoningensis The oldest conifer family is Thucydiaceae, which first appeared 300mya, but is now extinct. An early conifer was Thucydia mahonigensis (see left). Conifers first evolved during an ice age and this explains why they are so adapted to cold – needles and scales allow snow to slide off them easily and since there is little sun with which to make new leaves, being evergreen is an efficient way of surviving. Why some conifers have berries Taxus baccata As has been mentioned above, a number of conifers have fruit-like flesh surrounding their seeds, however, these are not real fruits. The botanical definition of a fruit is a matured ovary, usually with a seed inside it, but only Magnoliophyta Division (Angiosperms) plants have ovaries. The ovary, predictably, contains the egg, and when this egg is fertilised the ovary expands with sugars making it appealing to passing animals, the animals eat the fruit, carry the seed in their guts away from the parent plant and deposit it.

This is highly advantageous for the plant since it allow the species to spread, but without ovaries, conifers had to find a different way to create tasty fruit-like organs to entice animals. The conifer families that have acheived this are: Taxaceae, Podocarpaceae, Cephalotaxaceae and Cupressaceae, and in the relevant trees, cones have been reduced, often producing only one seed and this is surrounded by enlarged bracts, that provide the colour and flavour. This distinction is irrelevant to the animals that eat the bracts and to the plants that succeed in spreading their seed, but is significant when understanding the difference between conifers and flowering plants. The Parasitic Conifer: Parasitaxus usta Parasitaxus usta Parasitaxus usta is a woody shrub, less than 2m tall, that grows on the roots of only one other conifer, Falcatifolium taxoides, but has no roots of its own. Both are in the Podocarpaceae family and only grow in New Caledonia. Parasitaxus has purple scale leaves growing from small woody stems, like branches sticking out of the ground.

Although the foliage and shoots of Parasitaxus have chloroplasts which are usually used for photosynthesis, the plant does not photosynthesize and instead extracts sugars from the host plants by means of a fungus. There may even be a direct connection between the vascular systems of each plant, since the parasite actually grows into the roots of the host. This parasitism is unlike any seen in angiosperms. Further reading Gymnosperms The Division Pinophyta are part of a larger plant group called the Gymnosperms. Gymnosperms consist of four different divisions: Pinophyta, Cycadophyta, Ginkgophyta and Gnetophyta. Unlike more primitive plants such as mosses and ferns, gymnosperms have seeds rather than spores, but they do not have flowers or fruits like more recently evolved plants, the angiosperms (aka Flowering plants or Magnoliophyta Division). Gymnosperm means ‘naked seed’, because the seeds are not contained in a matured ovary, or fruit.

Most gymnosperms are wind pollinated, one exception being Welwitschia mirabilis (not a conifer, instead it is in the Gnetophyta Division, it will feature in a later blog) Coniferous Trees Follow Us Coniferous Trees Coniferous trees are characterized by needle or scale like leaves and the presence of cones in matured trees. The naked seeds (not encased in fruits) of coniferous trees, reveal that they are more primitive than hardwood. Advertisement Also known as softwoods, coniferous trees are taxonomically classified under the order Coniferales and phylum Pinophyta. Since conifers are non-flowering, but seed producing plant, they are included in the plant group, gymnosperms . Besides cones, another characteristic feature of these trees are the needle or scale like leaves, which are very different from the broad shaped deciduous trees. Interesting Facts According to the evolutionary theory, coniferous trees are more primitive than the flowering plants. Fossil data reveals the evolution of conifers in the carboniferous period. Nevertheless, all of them have a well-developed vascular system. Despite the common name softwood, some coniferous trees have very hard woods.

In fact, they are more tough and hard than the hardwood tree varieties. Discussed below are some of the amazing facts about coniferous trees, which you may find interesting: Identification of coniferous trees is done based on the leaves and cone. Say for example; pines and cedars have needle-shaped leaves, whereas scale like leaves are borne on matured cypress trees. Majority of the coniferous trees are evergreen, meaning they retain their green foliage throughout the year. While a very few species (e.g., tamarack and bald cypress) shed their leaves annually (deciduous habit). Coniferous trees are very diverse in their growth. There are coniferous shrubs as well, but the number of trees is higher than that of shrubs and bushes. The tallest tree species, redwood (about 300 feet tall and 8 feet wide) belongs to conifers. As mentioned already, the reproductive structure of conifers is cone. Pollination in coniferous trees is of anemophilous type, wherein wind transfers the pollens from male cone to the female cone for fertilization. Types Coming to types of coniferous trees, there are eight families under Pinophyta.

In total, more than 600 species of conifers are identified till date. The reduced leaf structure is one character shared by all coniferous trees. This serves as an adaptive feature for surviving in the cold climatic conditions. Leaves may be retained for as long as 15 years, depending upon the species. Mentioned below are some common coniferous trees: Pine: The pine family consists of more than 100 species. Four types of leaves are borne in pine trees, viz. seed leaves, juvenile leaves, scale leaves, and needle leaves. These conifers are long-lived, some of which are known to survive for more than 1000 years. Fir: It is grown for creating a privacy screen and defining landscape. Some cultivars of firs can grow up to 12 inches per year. The variety balsam fir is known to survive for about 200 years and more. Like other common conifers, fir trees have soft wood that are used for making plywood. Cypress: The most widely distributed conifers are cypresses. This family comprises shrubs, while a few of them are trees.

The leaves of cypress trees are needle like, but change to scales once the tree matures. Some varieties replace a portion of their leaves every year. Spruce: A commonly grown coniferous tree species, the spruce tree is remarkable for its rapid growth rate (about 12 inches per year). The branches are developed in a whorled pattern. Spruce has an attractive, conical-shaped canopy. Cedar: Native to very high altitudes and mountainous areas, cedar tree grows to a height of about 30-40 m. It is a popular ornamental plant in temperate regions. The wood has a mild scent and attractive texture, which makes it a valuable timber. Coniferous trees are commercially important, in terms of food source, resin extraction, and timber production. As per researches, they are the largest carbon sink available naturally. Hence, these trees play a crucial role in the overall balancing of global climatic condition.

Ningthoujam Sandhyarani Gymnosperms Gymnosperms About this site Gymnosperms: ~1,100 species Gymnosperms and Angiosperms together comprise the seed plants, which are heterosporous and keep their spores and gametophytes embedded within parental diploid tissue. Female gametophytes grow from the megaspore and are comprised of a few cells contained within diploid ovule tissue. Male gametophytes are even smaller and are packaged inside of diploid tissue as pollen. The male gametophyte is delivered to within a short distance of the female gametophyte through pollination, and when a sperm nucleus from the pollen fuses with the egg cell within the ovule, the resulting zygote develops into a diploid embryo packaged with a food source inside the seed. A miniature version of the next generation of diploid sporophyte thus already exists within the seed before it is released from the parent sporophyte. Although most of land plant and seed plant species diversity is found within flowering plants (Angiosperms), the Gymnosperms are vascular seed plants that dominate ecosystems over significant portions of the planet (particularly conifers in the northern hemisphere).

Gymnosperm means "naked seed," referencing that the ovules of these plants are not enclosed in a true fruit, as in Angiosperms. Gymnosperms include familiar evergreen trees such as pines and other Conifers as well as a few eccentric groups with low species diversity- the Gnetophytes, the Cycads, and Ginkgo. Molecular studies have supported the position of Cycads alone as the basal lineage among modern Gymnosperms, although support isn't great with some studies joining Ginkgo+Cycads. The Gnetophytes were once thought to be more closely related to Angiosperms rather than Gymnosperms, a hypothesis known as the anthophyte hypothesis, because they share the traits of double fertilization and vessel elements (scattered wide xylem cells) with angiosperms but not other Gymnosperms. However, most molecular studies find Gnetophytes to be part of a monophyletic Gymnosperm clade, although their placement within the Gymnosperms varies. The "Gnetifer" hypothesis places Gnetophyes as a sister group to the Conifers (shown in the tree at the top of the page).

Some molecular studies have actually placed Gnetophytes within Conifers as sister to the order Pinales, a hypothesis known as the "Gnepine" hypothesis, although neither hypothesis is strongly supported. The major issue clouding the placement of the Gnetophytes is that they are on a long, divergent branch with many mutations relative to other Gymnosperms. Regardless of whether the Gnepine or Gnetifer hypothesis is correct, it indicates the double fertilization and vessel elements seen in Gnetophytes and Angiosperms evolved independently (convergent evolution). Cycadophyta (Cycads): ~300 species Cycads are dioecious, with pollen and seeds often borne in cone-like structures. In some cases, the seeds are produced on structures that are more leaflike, known as megasporophylls. Cycads have pinnately compound leaves, and they are sometimes referred to as Sago "Palms" even though they are not closely related to that family of flowering plants. Some cycad species are commonly cultivated as ornamental plants.

Cycadales Zamiaceae: Zamia furfuracea (female cones) Ginkgophyta (Ginkgo): 1 species Ginkgo is a dioecious, broad-leaved, deciduous tree originally native to China. No known natural populations exist, though it has been cultivated for centuries. The "fruits" are actually fleshy seed coats (gymnosperm ovules are not contained in ovaries, which form the true fruits of angiosperms). Ginkgo seeds are considered a delicacy in some oriental cultures, although the rotting seeds release a rank smell around fruiting female trees. The fragrance comes from butyric acid, the same compound produced by rancid butter. For this reason, male trees are usually preferentially selected for ornamental purposes. Ginkgoales Ginkgoaceae: Ginkgo biloba (female in "fruit") Ginkgo, Maidenhair Tree Pinales Pinaceae (Pine Family): ~255 species In Georgia, only 3 families of Gymnosperms are present, and the most diverse by far is Pinaceae.

Pine species are particularly diverse in the state relative to other gymnosperms, although there are still only 10 native species here. Pinaceae have needle-like leaves and female strobili that resemble typical "Pine Cones," although cone size is highly variable. The scales on the cones are imbricate in Pinaceae, meaning they overlap in a spiral formation from the base to the apex. Pines are among the most economically important plants in the state, particularly Loblolly Pine (Pinus taeda), which is widely planted for timber and is much more common in the state now than it was historically. Slash Pine (Pinus elliotii) is often more widely planted on the outer coastal plain. The coastal plain of GA was once dominated by Longleaf Pine (Pinus palustris) savannah, and Longleaf extended commonly along the dryer ridges well into the piedmont and areas of NW GA.

Longleaf Pine tolerates fire much better than our other native pines, but once all the large trees were logged in the 1800s and early 1900s, fire suppression and conversion of most of the coastal plain to agriculture or plantations of other faster-growing pine species has left Longleaf Pine habitat as only tiny scattered remnant fragments. The christmas tree industry also gives Pinaceae added ecomomic significance. Historically, hemlock bark was collected for its concentrations of tannin, used for tanning leather. Turpentine is another historically important Pinaceae product. Examples: Abies fraseri ( female cones ), (leaves) Fraser Fir; Larix laricina American Larch, Tamarack; Picea rubens ( female cones ), (male strobili) , (leaves) Red Spruce; Pinus pungens Table Mountain Pine; Tsuga canadensis (male strobili) , ( female strobilus ), ( population ) Cupressaceae (Cypress Family): ~166 species Cupressaceae typically differ from Pinaceae in having cones with opposite, or at least, non-spirally-imbricate cones.

Some cones in Cupressaceae may be woody like Pinaceae, some are round/circular, and some have the cone scales highly modified and fleshy rather than woody, leading to a berrylike cone that is dispersed by birds in the same way as many angiosperm seeds are dispersed in fleshy ovary tissue (fruits). Cupressaceae usually have more scale-like leaves rather than linear needles, although one of our most common species, Baldcypress, has distinctly needle-like leaves that are deciduous in winter. Cupressaceae are popular ornamental conifers due to their dense foliage. Some are large enough to be very important timber trees (redwoods, sequoia, Western Red Cedar), and cedar wood is valuable due to its resistance to rot and pleasant, long-lasting fragrance. The fruit-like cones of Junipers are used in the production of gin. Coniferous tree | Article about coniferous tree by The Free Dictionary Coniferous tree | Article about coniferous tree by The Free Dictionary Also found in: Dictionary , Thesaurus , Wikipedia .

Pinophyta (pī'nŏf`ətə), division of the plant kingdom consisting of those organisms commonly called gymnosperms. The gymnosperms, a group that includes the pine, have stems, roots and leaves, and vascular, or conducting, tissue (xylem and phloem). In these plants the ovules, or young seeds, are exposed to the air at the time of pollination, hence the term gymnosperm, meaning naked seed. Pollination is always by wind. Because the seed-bearing structures of many gymnosperms are organized into a cone, or strobilus, these plants have been called conifers conifer [Lat.,=cone-bearing], tree or shrub of the order Coniferales, e.g., the pine, monkey-puzzle tree, cypress, and sequoia. Most conifers bear cones and most are evergreens, though a few, such as the larch, are deciduous. ..... Click the link for more information. ; because the leaves of many species are perennial, they have also been called evergreens.

Class Cycadopsida The class Cycadopsida, or cycads, are only the small evolutionary vestige of a large and varied group of plants that flourished in late Paleozoic and Mesozoic time. The only order of living cycads, the Cycadales, is dioecious, i.e., male and female cones are borne on separate plants. Although cycads resemble the palms in form and usually have erect stems that reach 50 ft (15 m) in height, they have very little wood; rather, they are supported largely by a hard outer layer of the stem. They have large, fernlike leaves and produce seeds in terminal cones. In their reproduction, pollen grains, or microspores, are transported by wind to the female spore case, or megasporangium. Within the microspore wall, motile flagellated sperms are produced, unlike the nonmotile sperms of the higher gymnosperms. Class Pinopsida The class Pinopsida is characterized by generally small, always simple leaves and by the active secondary growth of stem and root. Many members of this group flourished from Lower Carboniferous times to the Permian age.

Plants of the order Pinales (conifers) occur in the Northern Hemisphere; a few species occur within the tropics at sea level. Conifers are the most numerous of living gymnosperms and form large and relatively pure forests. Common examples of conifers are the pines, firs, spruces, redwoods, cedars, junipers, hemlocks, and larches. The wood of conifers is used extensively for construction of all kinds. It has no vessels and thus differs from the wood of angiosperm trees. Although conifers are called softwoods and angiosperm trees hardwoods, the wood of some pines is much harder than that of some angiosperms. Most conifers are monoecious, i.e., the male and female cones occur on the same tree. The microspores, or pollen grains, are produced in such vast abundance that clouds of pollen, carried on the wind, have settled on ships far at sea. In plants of the order Taxales ( yews yew, name for evergreen trees or shrubs of the genus Taxus, somewhat similar to hemlock but bearing red berrylike fruits instead of true cones.

Of somber appearance, with dark green leaves, the yew since antiquity has been associated with death and funeral rites. ..... Click the link for more information. ) the seeds, produced individually on short shoots, are surrounded by a conspicuous, fleshy covering. Other Classes Species- Taxus baccata L. Etymology: The name "Taxus baccata" is derived from the ancient Greek term "taxis" meaning "order or arrangement" and "baccata" meaning "carrying berries". The words "toxic" and "textile" are derived from the the root "taxus" due to the tree's toxicity and its bark's utility as a weaving material. The most common names for Taxus baccata are "English Yew," "Common Yew," or "European Yew." As these names suggest, Taxus baccata is found predominantly throughout England and the rest of Europe (See Habitat and Distribution ). "Yew" comes from Old English "iw" and can be traced back to Germanic and Gallic origin.

Taxus baccata was first classified in 1753 by Carl Linnaeus, who is credited as "the Father of Taxonomy" for his use of a binomial naming system, which we still use today. If you're interested in learning more about Carl Linnaeus, click here Method of Classification: Domain Euakrya: English yew is classified as a Eukaryote due to the presence of membrane bound organelles and a true nucleus within its cells. All other plants, animals (us included), protists, and fungi belong to the domain Eukarya. A couple specific examples of this broad group include the microscopic Saccharomyces cerevisiae (bread yeast) and the worlds largest land mammal Giraffa Camelopardalis (Giraffe) Kingdom Plantae: As you might have guessed by the name, the kingdom Plantae contains all of the plants of the world. Distinguishing characteristics from other kingdoms are cell walls composed of cellulose, and autotrophy, or the the ability to produce sugar by the process of photosynthesis. Other organisms that are members of kingdom Plantae include the apple tree and licorice fern .

For more information on photosynthesis and how the English yew gets its food check out: nutrient acquisition . Phylum Pinophyta: Organisms of this division are classified as gymnosperms, meaning "naked seeds." So these plants reproduce via seeds that are not contained in fruits, thus "naked". These naked seeds are usually contained in cones, but this is not always the case, as seen with reproduction in the yew trees. Along with having naked seeds , there are a few other obvious characteristics that define this group. Members of division Pinophyta are typically located in areas with cold winters. They also are the tallest, most massive, and longest living of any plants. Class Pinospida: These are all of the same organisms that are included in Pinophyta. So this taxanomic category isn't a smaller group within Pinophyta. Orders within phylum Pinophyta and class Pinospida include the Pinales (conifers) and Taxales (Yews). Order Taxales: This is the order of gymnosperms that include includes the yew family only. This is a morphological classification.

Genetic similarities between yew trees and other conifers may lead to a combining of Pinales and Taxales. Family Taxaceae: This family contains the genus Taxus, to see other organisms within this family see Phylogenetic Trees at the bottom of the page. Genus Taxus L.: Taxus refers to the seven or eight species of yew. The taxi are so similar that it is hard to distinguish between the different species. If one species were to be planted in the habitat of any other, the species would likely survive. In addition, these species vary in distribution but there are reproducing hybrids that exists between some species, further proving that some may actually be the same species. One other species of yew is the pacific yew , which can be found along the west coast of North America. For an even greater amount of info on the genus Taxus, click here Species Taxus baccata L.: Also called the European yew, English yew, or common yew, this species is the most widely known of all of the yew species. This slow growing and long lived tree is sparsely located across the continent of Europe.

Phylogenetic Trees: Phylogeny of Land Plants (constructed by Chad Kahles): The phylogenetic tree above shows where the conifers (coniferophyta or pinophyta) fit into the overall classification of land plants. The English yew is a conifer (highlighted in green), which means that it is vascular, has seeds, and a member of the gymnosperms. This tree is based on morphological characteristics. See below for a phylogenetic tree for family Taxaceae. Phylogeny of Taxaceae (constructed by Chad Kahles): The phylogenetic tree above where Taxus baccata fits within the family Taxaceae and genus Taxus. You can see Taxus baccata along with the other seven species of yew which it is closely related to. These species of yew are so similar that they are often only classified as separate species due to their geographic isolation rather than by morphological or genetic characteristics. There is great debate as to if there are more or less actual species of yew because they are so similar. For instance, all species of yew can flourish in another yew species habitat and yew species can readily form hybrids.

Check out one of the English yew's closest relatives: Taxus brevifolia . Pinophyta facts, information, pictures | Encyclopedia.com articles about Pinophyta The Columbia Encyclopedia, 6th ed. Copyright The Columbia University Press Pinophyta (pī´nŏf´ətə), division of the plant kingdom consisting of those organisms commonly called gymnosperms. The gymnosperms, a group that includes the pine, have stems, roots and leaves, and vascular, or conducting, tissue (xylem and phloem). In these plants the ovules, or young seeds, are exposed to the air at the time of pollination, hence the term gymnosperm, meaning naked seed. Pollination is always by wind. Because the seed-bearing structures of many gymnosperms are organized into a cone, or strobilus, these plants have been called conifers ; because the leaves of many species are perennial, they have also been called evergreens. Class Cycadopsida The class Cycadopsida, or cycads, are only the small evolutionary vestige of a large and varied group of plants that flourished in late Paleozoic and Mesozoic time.

The only order of living cycads, the Cycadales, is dioecious, i.e., male and female cones are borne on separate plants. Although cycads resemble the palms in form and usually have erect stems that reach 50 ft (15 m) in height, they have very little wood; rather, they are supported largely by a hard outer layer of the stem. They have large, fernlike leaves and produce seeds in terminal cones. In their reproduction, pollen grains, or microspores, are transported by wind to the female spore case, or megasporangium. Within the microspore wall, motile flagellated sperms are produced, unlike the nonmotile sperms of the higher gymnosperms. Class Pinopsida The class Pinopsida is characterized by generally small, always simple leaves and by the active secondary growth of stem and root. Many members of this group flourished from Lower Carboniferous times to the Permian age. Plants of the order Pinales (conifers) occur in the Northern Hemisphere; a few species occur within the tropics at sea level. Conifers are the most numerous of living gymnosperms and form large and relatively pure forests.

Common examples of conifers are the pines, firs, spruces, redwoods, cedars, junipers, hemlocks, and larches. The wood of conifers is used extensively for construction of all kinds. It has no vessels and thus differs from the wood of angiosperm trees. Although conifers are called softwoods and angiosperm trees hardwoods, the wood of some pines is much harder than that of some angiosperms. Most conifers are monoecious, i.e., the male and female cones occur on the same tree. The microspores, or pollen grains, are produced in such vast abundance that clouds of pollen, carried on the wind, have settled on ships far at sea. In plants of the order Taxales ( yews ) the seeds, produced individually on short shoots, are surrounded by a conspicuous, fleshy covering. Other Classes The class Ginkgoopsida contains the contains the ginkgo , Ginkgo biloba, the last surviving species of a once large and flourishing group of gymnosperms. The class Gnetopsida contains three genera in separate orders, all of great botanical and evolutionary interest.

Gnetum is a tropical tree or shrub with broad leaves much like those of an angiosperm. Ephedra is a low shrub with scalelike leaves that grows in arid regions of western North America and in China; from it is produced the traditional Chinese herbal medicine ma huang and the drug ephedrine . Welwitschia, a desert plant of SW Africa, typically has only two large, leathery leaves that persist for the life of the plant, which can be as long as 1,500 years. Cite this article Pick a style below, and copy the text for your bibliography. MLA A Dictionary of Biology © A Dictionary of Biology 2004, originally published by Oxford University Press 2004. Coniferophyta A phylum of seed-bearing plants comprising the conifers, including the pines, firs, and spruces. Conifers have an extensive fossil record going back to the late Devonian. The gametes are carried in male and female cones , fertilization usually being achieved by wind-borne pollen.

The ovules and the seeds into which they develop are borne unprotected (rather than enclosed in a carpel, as are those of the Anthophyta ). Internal tissue and cell structure of these species is not as advanced as in the angiosperms. Conifers are typically evergreen trees inhabiting cool temperate regions and have leaves reduced to needles or scales. The wood of conifers, which is called softwood in contrast to the hardwood of angiosperm trees, is widely used for timber and pulp. See also gymnosperm . Cite this article A Dictionary of Plant Sciences © A Dictionary of Plant Sciences 1998, originally published by Oxford University Press 1998. Coniferophyta (Pinophyta) The biggest division of gymnosperms , with a long fossil history, comprising trees and shrubs, nearly all of which are evergreen, commonly with monopodial crowns. Most are resinous. The wood lacks vessels (see TRACHEA and VESSEL ELEMENT ). Conifers are extremely important for timber and paper production. The leaves are often needle- or scale-like. Fertile parts occur in unisexual cones, variously containing sterile scales.

Stamens are borne on commonly peltate scales. The ovule and seed are naked and borne on a scale. They first appear as fossils in Carboniferous rocks. There are about 550 extant species. Cite this article

Question: Pinophyta trees are characterized by what reproductive fruit?
Answer: Cones