Hypnodendron comosum | |
---|---|
Scientific classification | |
Kingdom: | Plantae |
Division: | Bryophyta |
Class: | Bryopsida |
Subclass: | Bryidae |
Order: | Hypnodendrales |
Family: | Hypnodendraceae |
Genus: | Hypnodendron |
Species: | H. comosum |
Binomial name | |
Hypnodendron comosum (Labill.) Mitt. | |
Varieties | |
Hypnodendron comosum var. comosum Contents |
Hypnodendron comosum, commonly known as palm moss or palm tree moss, is a ground moss which can be divided into two varieties: Hypnodendron comosum var. comosum and Hypnodendron comosum var. sieberi. [1] Both Hypnodendron varieties most commonly grow in damp locations in the temperate and tropical rainforests of New South Wales, Victoria, and Tasmania in southern Australia and in New Zealand. [2] [1] [3]
This "miniature forest" dendroid species is viewed by David Meagher and Bruce Fuhrer in their publication A Field Guide to the Mosses and Allied Plants of Southern Australia as one of the most beautiful and unique species of mosses in the southern region of Australia. [4] While both varieties are extremely similar, they are easily identified by their elevation above other moss and lichen species within their ecosystem. Positioned atop an erect stem, the branches form an umbrella shape, the source of the common name "palm tree moss". [2] [5] [4]
The appearance for both varieties is similar with both sharing many of the same features. Resembling the trunk of the tree, the stems are elongated and narrow growing between 2–9 cm (0.79–3.54 in) in length. They are black or brown in colour and covered in trichome hairs and small leaves. The stem reaches up to a green umbrella shaped arrangement of fronds at the top. The horizontally spreading fronds are shaped umbellate to pinnate and grow up to 5 cm (2.0 in) in diameter. Each spreading frond forms many small branches each reaching 2–5 mm (0.079–0.197 in) in length. This gives the umbrella shape a clumpy, palm-like look. The branch leaves are triangular-ovate and yellow-green in colour. The costa is green or brown and margins are serrate toward the tip. [2] The sporophyte arises from the centre of the female gametophyte and forms a long seta on which a capsule is borne. H. comosum bares anywhere between 4–12 sporophytes. The seta is long and thin and reaches between 2–4 cm (0.79–1.57 in) in length. The capsule is orange or brown in colour and reaches around 2–5 mm (0.079–0.197 in) in length. They are cylindrical in shape. The operculum is the cap or covering to the spores, and once this falls off, the spores are passively dispersed via the peristome. [2] While both species are similar, Hypnodendron comosum var. comosum is unique in that it is the smaller, more compact of the two. Most commonly located in Tasmania, its branches are compactly arranged, making this variety seem clumped and tightly packed. Located on mainland Australia, Hypnodendron comosum var. siberi is taller in form and the branches are much more loosely arranged. [2]
Like all bryophyte species, Hypnodendron species are non-vascular, meaning the vasculature or ducts within the tissues in which water, nutrients and sugars are transported around the plant are non-existent. [3] Bryophytes also lack true roots but are anchored to the substrate by rhizoids. Unlike vascular plants that use their roots to exchange gas and extract nutrients and water from the soil, bryophytes are able to do this over the leaf surface, depositing nutrients and water where they are required. [4] [3]
The plant is commonly located in wet forests and rainforests consisting of moist humeric layerings with loamy soil composition. Favouring wet rocks, tree roots, the base of live trees and tree ferns, it is most commonly located in areas with large amounts of decaying logs and decomposing matter. [2] [1] This species forms clumps like colonizing patterns in dry conditions and, when conditions are moist, H.comosum forms small forest mats with large numbers, indicating wetter environments are preferable. [1] [4]
Hypnodendron comosum is endemic to the Australian states of New South wales, Victoria, and Tasmania and to New Zealand, Stuart Island, and the Campbell Islands.
Since it is located in New Zealand as well as Australia, this indicates that the species predates Gondwanaland, suggesting that this species may be included as one of the earliest species to diverge from water to land and may give vital insight toward how vascular plants evolved. [2] [1] [3] Hypnodendron comosum var. sieberi is more commonly located on mainland Australia and the northern South Island of New Zealand, whereas H. c. var. comosum is more commonly located in Tasmania, the southern South Island of New Zealand, and the islands located in the southern ocean. [2]
Like all mosses, Hypnodendron comosum has an alternation of generations. This means that there are two generations that exist in a full life cycle of this plant. Those generations are named the sporophyte stage and the gametophyte stage. [4] The gametophyte stage is the fertilization event of the lifecycle and involves female and male gametangia. In this stage the antheridium fertilizes the haploid egg within the archegonia with haploid sperm producing a diploid zygote. This zygote then divides via mitosis and forms the sporophyte. [3] The sporophyte stage is the spore-forming event of the lifecycle. Once the zygote has begun to enlarge, the seta elongates and develops a sporangium on the end in the form of a capsule. This capsule consists of sporogenous tissue, a peristome to regulate the dispersal of spores, and an operculum to protect early release. [3] Once spores are released, they germinate and grow into a narrow long rhizoid-like form named a protonema. This protonema develops buds which grow to become either a male or female gametophyte. The male gametophyte is named the antheridium and the female the archegonium. This is the gametophyte stage. [3]
A gametophyte is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the sexual phase in the life cycle of plants and algae. It develops sex organs that produce gametes, haploid sex cells that participate in fertilization to form a diploid zygote which has a double set of chromosomes. Cell division of the zygote results in a new diploid multicellular organism, the second stage in the life cycle known as the sporophyte. The sporophyte can produce haploid spores by meiosis that on germination produce a new generation of gametophytes.
Alternation of generations is the predominant type of life cycle in plants and algae. In plants both phases are multicellular: the haploid sexual phase – the gametophyte – alternates with a diploid asexual phase – the sporophyte.
Bryophytes are a group of land plants, sometimes treated as a taxonomic division, that contains three groups of non-vascular land plants (embryophytes): the liverworts, hornworts, and mosses. In the strict sense, the division Bryophyta consists of the mosses only. Bryophytes are characteristically limited in size and prefer moist habitats although some species can survive in drier environments. The bryophytes consist of about 20,000 plant species. Bryophytes produce enclosed reproductive structures, but they do not produce flowers or seeds. They reproduce sexually by spores and asexually by fragmentation or the production of gemmae. Though bryophytes were considered a paraphyletic group in recent years, almost all of the most recent phylogenetic evidence supports the monophyly of this group, as originally classified by Wilhelm Schimper in 1879. The term bryophyte comes from Ancient Greek βρύον (brúon) 'tree moss, liverwort' and φυτόν (phutón) 'plant'.
The Marchantiophyta are a division of non-vascular land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information.
A sporophyte is the diploid multicellular stage in the life cycle of a plant or alga which produces asexual spores. This stage alternates with a multicellular haploid gametophyte phase.
Hornworts are a group of non-vascular Embryophytes constituting the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. As in mosses and liverworts, hornworts have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information; the flattened, green plant body of a hornwort is the gametophyte stage of the plant.
Fissidens adianthoides, the maidenhair pocketmoss, is a moss in the family Fissidentaceae. It was first collected by Hedwig in 1801.
Plant reproduction is the production of new offspring in plants, which can be accomplished by sexual or asexual reproduction. Sexual reproduction produces offspring by the fusion of gametes, resulting in offspring genetically different from either parent. Asexual reproduction produces new individuals without the fusion of gametes, resulting in clonal plants that are genetically identical to the parent plant and each other, unless mutations occur.
Hymenophyllum australe, commonly known as austral filmy fern, is a relatively large rupestral and epiphytic fern, indigenous to eastern Australia and New Zealand. It belongs to the unique Hymenophyllum genus, which are characterised by their thin membranous fronds that are seldom more than one cell thick, with the exception of regions over and around veins. Hymenophyllum australe is distinctive in that the fronds are typically thicker than other Hymenophyllum species, often being up to 2-3 cells thick.
Tetraphis pellucida, the pellucid four-tooth moss, is one of two species of moss in the acrocarpous genus Tetraphis. Its name refers to its four large peristome teeth found on the sporophyte capsule.
Splachnaceae is a family of mosses, containing around 70 species in 6 genera. Around half of those species are entomophilous, using insects to disperse their spores, a characteristic found in no other seedless land plants.
Pogonatum urnigerum is a species of moss in the family Polytrichaceae, commonly called urn haircap. The name comes from "urna" meaning "urn" and "gerere" meaning "to bear" which is believed to be a reference made towards the plant's wide-mouthed capsule. It can be found on gravelly banks or similar habitats and can be identified by the blue tinge to the overall green colour. The stem of this moss is wine red and it has rhizoids that keep the moss anchored to substrates. It is an acrocarpous moss that grows vertically with an archegonium borne at the top of each fertilized female gametophyte shoot which develops an erect sporophyte.
Climacium dendroides, also known as tree climacium moss, belongs in the order Hypnales and family Climaciaceae, in class Bryopsida and subclass Bryidae. It is identified as a "tree moss" due to its distinctive morphological features, and has four species identified across the Northern Hemisphere. The species name "dendroides" describes the tree-like morphology of the plant, and its genus name came from the structure of the perforations of peristome teeth. This plant was identified by Weber and Mohr in 1804. They often have stems that are around 2-10 cm tall and growing in the form of patches, looking like small palm-trees. They have yellow-green branches at the tip of stems. The leaves are around 2.5-3 mm long, with rounder stem leaves and pointier branch leaves. Their sporophytes are only abundant in late winter and early spring, and appears as a red-brown shoot with long stalk and cylindrical capsules.
Polytrichum strictum, commonly known as bog haircap moss or strict haircap, is an evergreen and perennial species of moss native to Sphagnum bogs and other moist habitats in temperate climates. It has a circumboreal distribution, and is also found in South America and Antarctica.
Buxbaumia viridis, also known as the green shield-moss, is a rare bryophyte found sporadically throughout the northern hemisphere. The gametophyte of this moss is not macroscopically visible; the large, distinct sporophyte of B. viridis is the only identifying structure of this moss. This moss can be found singularly or in small groups on decaying wood, mostly in humid, sub-alpine to alpine Picea abies, Abies alba, or mixed tree forests. This moss is rare and conservation efforts are being made in most countries B. viridis is found in.
Andreaea rupestris is a species of moss in the class Andreaeopsida, are commonly referred to as the "lantern mosses" due to the appearance of their dehisced sporangia. It is typically found on smooth, acidic, exposed rock in the Northern hemisphere. It exhibits the common features of the genus Andreaea such as being acrocarpous, having dark pigmentation, lacking a seta, and bearing 4 lines of dehiscence in its mature sporangia, but can be further identified upon careful examination of its gametophytic leaves which have an ovate base to a more blunt apex compared to other similar species.
Tortula muralis, commonly known as wall-screw moss, is a species of moss in the family Pottiaceae. T. muralis is found throughout the world.
Polytrichastrum formosum, commonly known as the bank haircap moss, is a species of moss belonging to the family Polytrichaceae.
Podomitrium phyllanthus is a thalloid liverwort in the family Pallaviciniaceae. It is found in wet forests and rainforests of Australia, New Zealand and New Caledonia.
Dicranoloma billardierei is a species of bryophyte in the genus Dicranoloma. This moss is extremely common in wet rainforest habitats. In the field, Dicranoloma billardierei, is often confused with Dicranoloma robustum and Dicranoloma fasciatum. However, the short and obtuse nature of the leaves make this moss normally very distinctive.