Most species in this phylum typically grow on moist soil in shaded areas, but some are found growing in … Anthocerotophyta is the least diverse phylum of the bryophytes, however its distribution is widespread, with Antarctica being the only continent in which they are not found. The last phylum, Gnetophyta, is a diverse group of plants that produce vessel elements in their wood. Welwitschia produces extremely long leaves and is found in the deserts of southwestern Africa (Figure below). Visual Connection Questions. Conifers are the dominant phylum of gymnosperms, with the most variety of species. After fertilization, the ovary thickens and forms a fruit. Ginkgo biloba is considered to be dioecious, or (possessing) male and female organs on different trees; because of this we will take a careful look at both the male and female plants. GNETOPHYTA- gymnosperm 1. Double fertilization, which leads to formation of polyploid endosperm tissue. Gymnosperms: Cycad Cones. Reproduction. Maxfocus/iStock/Getty Images Plus. COMPARISON OF STRUCTURES IN GYMNOSPERMS Coniferophyta Cycadophyta Ginkgophyta Gnetophyta LEAVES Needle-like (small, long & narrow) Compound leaves (resembles palms or ferns) Fan-shaped leaves Broad leaves like angiosperms SEEDS Seeds in cones Seeds in cones Seeds are completely exposed Seeds in cones arranged in clusters … The gnetophytes are reduced to three far-flung and remarkably different genera (each genus in its own order). However, these three phyla are not closely related phylogenetically to each other. Coniferophytes. The fourth phylum (the Gnetophyta) are considered the closest group to angiosperms because they produce true xylem tissue. However, the similarities in reproductive structures serve to unite the taxa (see the description below). The gnetophytes are a small group of vascular seed plants composing the phylum Gnetophyta, which is one of four phyla of gymnosperms that have living representatives. Simple microgametophytes and megagametophytes. INTRODUCTION TO THE GNETOPHYTA. At what stage does the diploid zygote form? Ephedra is an important member of this group, since this desert shrub produces the ephedrine used to treat asthma and other conditions. They have very few vegetative synapomorphies except decussate leaves. Examples of conifers include pines, sequoias, firs, hemlock, and spruces. Stamens with two pairs of pollen sacs. Gnetophyta is heterosporous and, in addition, produce highly specialized, complex reproductive and dispersal structures called seeds. Reproductive structures are located in a flower. Flowers, the means of reproduction; Ovules surrounded by two integuments. The Gnetophyta include only three genera Ephedra, Gnetum, and Welwitschia—each of which belongs to a … Gnetophyta seeds are said to be "naked" since they lack a particular sort of protective covering characteristic of Anthophyta. The microgametophyte is a three‐nucleate structure, the megagametophyte an eight‐nucleate one. Female Plant A female Ginkgo biloba produces seeds that are covered by an outer layer, sometimes referred to … Gnetophyta – Evolution • Share features with gymnosperms AND angiosperms – Gymno: seeds not enclosed in ovary – Angio: vessels in wood, somewhat flower-like structures, double fertilization • BUT some primitive angiosperms do not have vessels (e.g., Winteraceae) • Recent data suggest a … Gnetophytes, in the phylum Gnetophyta, are a very small and unusual group of plants. Gnetophyta are therefore said to be "gymnospermous." The Coniferophyta division contains conifers, which have the greatest variety of species among gymnosperms.Most conifers are evergreen (retain their leaves throughout the year) and include some of the largest, tallest and oldest trees on the planet. 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