Hypnodendron comosum

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Hypnodendron comosum
Hypnodendron comosum.JPG
Scientific classification OOjs UI icon edit-ltr.svg
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
Hypnodendron comosum var. sieberi

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]

Appearance

Hypnodendron comosum var.comosum (left) and Hypnodendron comosum var. sieberi (right) Hypnodendron comosum va.comosum and Hypnodendron comosum va. sieberi.png
Hypnodendron comosum var.comosum (left) and Hypnodendron comosum var. sieberi (right)
Labeled features of Hypnodendron comosum var. sieberi Hypnodendron comosum va. sieberi.png
Labeled features of Hypnodendron comosum var. sieberi

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]

Physiology

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]

Habitat

This image shows the filtered amounts of light, distribution and other communities of moss and the different levels of understory. This is a rainforest located in Tasmania. Habitat of Hypnodendron comosum.JPG
This image shows the filtered amounts of light, distribution and other communities of moss and the different levels of understory. This is a rainforest located in Tasmania.
Hypnodendron comosum community taken in Tasmania's wilderness Hypnodendron comosum community.jpg
Hypnodendron comosum community taken in Tasmania's wilderness

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]

Geographical distribution

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.

Distribution of both varieties of Hypnodendron comosum, H. c. var. comosum and H. c. var. sieberi Distribution of both varieties of Hypnodendron comosum.png
Distribution of both varieties of Hypnodendron comosum, H. c. var. comosum and H. c. var. sieberi

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]

Phylogeny

Phylogenetic tree of Hypnodendron comosum Phylogeny tree of Hypnodendron comosum.png
Phylogenetic tree of Hypnodendron comosum

Life cycle

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]

Related Research Articles

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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.

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Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophytasensu stricto. Bryophyta may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hornworts. Mosses typically form dense green clumps or mats, often in damp or shady locations. The individual plants are usually composed of simple leaves that are generally only one cell thick, attached to a stem that may be branched or unbranched and has only a limited role in conducting water and nutrients. Although some species have conducting tissues, these are generally poorly developed and structurally different from similar tissue found in vascular plants. Mosses do not have seeds and after fertilisation develop sporophytes with unbranched stalks topped with single capsules containing spores. They are typically 0.2–10 cm (0.1–3.9 in) tall, though some species are much larger. Dawsonia, the tallest moss in the world, can grow to 50 cm (20 in) in height. There are approximately 12,000 species.

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<i>Pogonatum urnigerum</i> Species of moss

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.

<i>Climacium dendroides</i> Species of moss

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.

<i>Polytrichum strictum</i> Species of moss

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.

<i>Buxbaumia viridis</i> Species of moss

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<i>Andreaea rupestris</i> Species of moss

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<i>Tortula muralis</i> Species of moss

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<i>Polytrichastrum formosum</i> Species of moss

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<i>Dicranoloma billardierei</i> Non-vascular plant

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References

  1. 1 2 3 4 5 Frey, W.; Dalton, Patrick J. (1996). "Hypnodendron comosum - community in Tasmania". Nova Hedwigia. 62 (1–2): 215–220. ISSN   0029-5035.
  2. 1 2 3 4 5 6 7 8 "Australian Mosses Online". Department of Agriculture, Water and the Environment . Retrieved 9 March 2014.{{cite web}}: CS1 maint: url-status (link)
  3. 1 2 3 4 5 6 7 Raven, Peter H.; Evert, Ray F.; Eichhorn, Susan E. (2005). Biology of Plants (Seventh ed.). New York: W.H. Freeman. ISBN   0-7167-1007-2.[ page needed ]
  4. 1 2 3 4 5 Meagher, David; Fuhrer, Bruce (2003). A Field Guide to the Mosses and Allied Plants of Southern Australia. Flora of Australia Supplementary Series. Vol. 20. Melbourne: Australian Biological Resources Study/The Field Naturalists Club of Victoria. ISBN   978-0-642-56828-1.[ page needed ]
  5. Bell, Neil E.; Newton, Angela E. (January–March 2005). "The Paraphyly of Hypnodendron and the Phylogeny of Related Non-Hypnanaean Pleurocarpous Mosses Inferred from Chloroplast and Mitochondrial Sequence Data". Systematic Botany . 30 (1): 34–51. doi:10.1600/0363644053661896. JSTOR   25064039. S2CID   86280908.