Abulais Shomrat

Abulais Shomrat

Lycopodium: The Creeping Pines

Systematic Position Division: Lycophyta / Lepidophyta Class: Eligulopsida Order: Lycopodiales Family: Lycopodiaceae Genus: Lycopodium Also known as club mosses, Lycopods, creeping pines or tailing pines. Ligule: A membranous outgrowth projecting from the leaf sheath. On the basis of ligule, Lycophyta has 2 classes: Eligulopsida: Lycopodium phylloglossum Liqulopsida – Isoetales, Selaginellales …

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Psilotum: The Whisk Fern

Psilotum commonly known as Whisk-fern. Salient features of Pilotum The sporophytes are dichotomously branched with an underground trhizome and upright branches. The upright branches are leafless. Rhizoids present instead of root. Stem has a relatively simple vascular cylinder. The sporangia are born in groups (trilocular) and form synangioa. Spores produced …

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Introduction to Pteridophyta

The word cryptogams is a synthesis of two Greek terms kruptos meaning ‘hidden’ and gamos meaning ‘wedded’. This single term encompasses all plants that reproduce by means of spores and, do not produce seeds. The algae, fungi, bryophytes and pteridophytes are all cryptogams. The pteridophyta are treated as vascular cryptogams …

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Classification of Pteridophytes

The term Pteridophyta was first coined by Haeckel. Eichler (1883) divided the plant kingdom into Cryptogamia and Phanerogamia. The Cryptogamia was further divided into Thallophyta. Bryophyta and Pteridophyta. Engler (1909) included the Bryophyta and Pteridophyta under Embryophyta. Due to discovery of the fossil plants, the classification of Pteridophytes has undergone …

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Origin of Pteridophytes

They are the earliest known vascular plants which originated in the Silurian period (400 million years ago) of Palaeozoic Era and subsequently diversified and formed the dominant vegetation on earth during Devonian to Permian period. There are controversies regard­ing their origin and evolution. There are two broad theories about their …

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Telome Theory

A telome is defined as “branch having no leaves but dichotomous branching at either apex or at base or both” i.e., it is the point of the most distal dichotomy to the tip of a branch. The connecting axes between dichotomies are called mesomes. Functionally, telomes are of two types …

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Polyembryony: Multiple Embryos in a Seed

The phenomenon of polyembryony, i.e., the occurrence of mo re than one embryo in a seed, has attracted much attention ever since its initial discovery in the orange by Leeuwenhoek (1719). Ernst (1918) and Schnarf (1929), who have reviewed the older literature, classify it into two types—”true” and “false”—depending on …

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Apomixis: A Subistitution for Sexual Reproduction

Apomixis maybe defined (Winkler, 1908, 1934) as the substitution for sexual reproduction (amphimixis) of an asexual process which does not involve any nuclear fusion. For the sake of convenience it may be subdivided into four classes. Non-recurrent apomixis Recurrent apomixis Adventive embryony Vegetative propagation Non-recurrent apomixis In the first, or …

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