Flora (Plants)

Angiosperms

The sanctuary harbors more than 951 taxa belonging to 150 families (Sasidharan-1997). This represents nearly 25% of the total flowering plants estimated from Kerala (3800 species). Of the 951 species of flowering plants, dicotyledons dominate with 715 species belonging to 432 genera and 100 families. Monocotyledons are represented by 236 species under 149 genera and 18 families. The top ten families with respect to species richness are Orchidaceae (70 species and 44genera), Leguminacea (70,43), Poaceae (66,49), Rubiaceae (66,32), Euphorbiaceae (49,25), Asteraceae (29,21), Cyperaceae (29,10), Acanthaceae (28,16), Anoniaceae (19,13), and Lauraceae (19,8).

About 45% of the species belong to the above-mentioned families. Among the 118 families, 23 dicots and 7 monocots are represented by one species each.

The Shendurney Wildlife Sanctuary is the type locality of many of the endemics lying along the Aryankavu-Kulathupuzha valley. Of the 951 species recorded from the sanctuary, 309 are Western Ghats endemic, ie. 32% endemicity. This represents 24% of the endemic plants of Kerala (1272). Rubiaceae has the highest number of endemics with 29 species, followed by Orchidaceae (22), Lauraceae (16), Euphorbiaceae (15), Annonaceae and Legumincseae (13 each) and Aracaceae (8).

Of the reported 951 species, 100 species belong to the threatened categories representing 22% of the total threatened plants of Kerala (490). Two new species viz. Polyalthia shendurnii and Ardisia stonei are reported from the sanctuary (Sasidharan-1997). Five species are collected from the sanctuary as new records of occurrence for Kerala.

Floristic wealth

  1. Angiosperms – 951 species – 309 (Endemic) – 100 (Threatened) – Sasidharan 1997
  2. Gymnosperms – 3 species – Mohan, TBGRI
  3. Bryophytes – 13 species – Muktesh, 2001
  4. Pteridophytes – 78 species – Muktesh, 2001
  5. Lichens – 16 species – Muktesh, 2001
  6. Algae – 22 species – Unnithan. et.al 2000
  7. Desmids – 6 species – Unnithan. et.al 2000
  8. Diatoms – 15 species – Unnithan. et.al 2000

Flora (Lower Groups) in Shendurney Wildlife Sanctuary.

Lichens

Although lichens are often treated as a separate plant division, lichenologists now consider these as a part of the fungi. Over 20,000 species of lichens have been described so far. Lichen-fungi differ little from other parasitic fungi, except that the lichen-fungal hyphae and algal cells are so mutually dependent that the resulting association behaves as a single plant. Lichens probably illustrate the most perfect example of symbiosis, in which each partner is dependent on the other for existence. This association (lichen) reproduces as an association rather that as an algae or a fungus. The mycobiont (fungal partner) cannot reproduce itself or live independently. Most instances the algal partner is also unable to survive except as an algal component of lichen. However, under pure cultural condition the mycobiont or fycobiont can reproduce sexually. The mycobiont usually gives the lichen its growth morphology and does not exist in a non-lichenised state. The sexual reproductive structures are essentially fungal.

Most lichens contain a single species of algae coming under either green algae or blue green algae. The mycobiont is generally an ascomycete but a few tropical basidiomycetes, some deuteromycetes and reportedly a single phycomycete lead a lichenised existence.

The lichen thallus may be unstratified or stratified. In the unstratified type the algal cells are scattered throughout. The growth form of a lichen thallus is constant for a given species. A crustose thallus may be unstratified or stratified. In stratified crustose form the lichen is a thin crust closely adherent to the substrate. The hyphae in the upper portion of the crust form an upper cortex. These hyphae are usually tightly compacted and highly gelatinized. The cells of the algal layer, which underlies the cortex are surrounded by a loose network of hyphae. Below the algal layer is medulla of varying thickness composed of loosely arranged hyphae. The lowermost hyphae act as rhizoidal attaching the thallus to the substratum.

The folios thallus possess an upper cortex an algal layer and a medulla. The thallus can be carefully pealed intact from the substrate. In some foliose lichens the thallus may be attached by a single bundle of hyphae forming a central cord. The rest of the thallus expands over the single point of attachment. In others, the thallus is attached by a number of hyphal bundles. Depending upon the species, the foliose thallus may possess or may lack a lower cortex of densely packed hyphae beneath the medulla.

The squamulose thallus is structurally similar to the foliose type, however, the squamulose thallus is made up of many small lobes which may be loosely attached to each other. In some species of Cladonia these lobes (squamules) form colonies in which each squamule is free of its neighbour.

The fruiticose thallus is shrub like with cylindrical or flattened branches. Branching is either simple or complex. The thallus may be stiffy, erect or pendulous, some pendulous forms. Most fruiticose thallii are stratified.

The gelatinous thallus is essentially unstratified with a blue green alga dominating the structure, the fungus is scarcely apparent.

These lichens are either black or bluish. The name is derived from the texture of the moist lichen.

Bryophytes

The mosses and moss allies belong to a single division, the bryophytes. They are generally divided into three classes. Hepaticae (liverworts), anthocerotales (hornworts) and mosci (mosses). This division includes the most primitive of the green land plants.

The bryophytes are archeogoniate plants like the primitive vascular plants, bryophytes posses a peculiar multicellular female sex organ the archeogonium which is always flask shaped and the male sex organ antheridium which is spherical or elongate. All bryophytes are small, the largest erect forms are less than 60cm tall; some creeping or aquatic mosses are more than a meter long and some epiphytic mosses reach lengths of more than 60 meters.

Most bryophytes are strictly terrestrial and grow in humid environment, some grow in arid sites and a few are essentially aquatic.

The hepaticae is separated into six well-differentiated orders. The most primitive of hepaticae is generally considered to be the calobryales and the most advanced the marchantiales.

Anthocerotales

These resemble the thallus liverworts but number of significant features separates this class from other bryophytes. Over 100 species under 5 genera have been included under one order anthocerotales containing a single family. All members of the order have a thallus gametophyte that normally forms a rosette. Six organs are sunk deep in the upper layer of the bisexual thallus. The sporophyte is an elongate spindle attached to the gametophytes by its swollen hostorian like base, the foot. The sporangium generally ruptures along two preformed lines of weakness.

Mosci (mosses)

The mosses are readly distinguished from the hepaticaes and hornworts by having a leafy gametophyte, leaves are in three to five tiers. The leafy gametophyte arises from a filamentous protonema. The sporophyte is of firm tissue, spores are produced in a capsule which is covered by a calyptra (cap). The capsules open by means of small lid (operculum) that breaks off the top of the capsule.

Pteridophytes.

This division of vascular plants encompasses the ferns and several plants of the Devonian, referred to as preferns. The ferns are distinguished from most other plants by large, feathery leaves that in most cases unroll from the tip during growth, and the possession of sporangia on the undersurface of the leaf or occasionally on special fronds.

During the present preliminary survey of the lower groups of plants in the Shendurney Wildlife Sanctuary area 16 species of Lichens, 13 species of mosses and 78 species of pteridiphytes were collected and enumerated.

Phytoplankton

The total number of plankton (density) was relatively very high in the reservoir. The green algae had a poor contribution (av. 16.6%) among the plankton groups. On the contrary, the desmids had a very high percentage [76.7%] with a density as high as 1.03million units/m2 indicating an oligotrophic nature for the reservoir. Such high density for the desmids is unusually high compared to that of other reservoirs in the region.

The poor productive nature of the reservoir is also reflected in the low density (3.42%) of blue green algae. Only Anacystic species had a reasonable count among the blue greens. Other blue green algal species such as Anabaena, Lyngbya, and Nostoc, which are strong indicators of eutrophication and pollution, were virtually absent in this water body. Even the Oscillatoria has a negligible contribution of 0.18%. The pattern of distribution and abundance of the phytoplankton supported the argument that the reservoir had a low inherent capacity for biological production.

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