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Plants also have vestigial parts, including functionless stipules and carpels, leaf reduction of Equisetum, paraphyses of Fungi. [35] Well known examples are the reductions in floral display, leading to smaller and/or paler flowers, in plants that reproduce without outcrossing, for example via selfing or obligate clonal reproduction. [36] [37]
Evidence for common descent comes from the existence of vestigial structures. [72] These rudimentary structures are often homologous to structures that correspond in related or ancestral species. A wide range of structures exist such as mutated and non-functioning genes, parts of a flower, muscles, organs, and even behaviors.
Areoles represent highly specialized branches on cacti. They evolved as abortive branch buds while their spines evolved as vestigial leaves. [2] In branched cacti, such as Opuntioidiae and the saguaro, new branches grow from areoles, because that is where the buds are. The development of the areole seems to have been an important element in the ...
[3] [4] The flowers on the lower parts of the plant are cleistogamous (self-pollinating) while the tops of the stems have chasmogamous (cross-pollinating) flowers which may be sterile. [5] Beechdrops contain very small alternate, scale like leaves, which are a vestigial structure from an ancestor which was photosynthetic. [6]
The male flowers have 9 to 15 fertile stamens; the innermost circle of stamens can be found at the base of the stamen glands. Usually the stamens are longer than the anthers, which in turn consist of two chambers and are directed inwards or sideways. The vestigial ovary is negligible or absent. The base of the flower is small and flat.
Plants of the World: An Illustrated Encyclopedia of Vascular Plants. Chicago, Illinois: Kew Publishing and The University of Chicago Press. ISBN 978-0-226-52292-0. Coombes, Allen (2012). The A to Z of Plant Names: A Quick Reference Guide to 4000 Garden Plants. Portland, Oregon: Timber Press. ISBN 978-1-60469-196-2. Cullen, Katherine E. (2006).
Here is a list of examples in which unrelated proteins have similar functions with different structure. The convergent orientation of the catalytic triad in the active site of serine and cysteine proteases independently in over 20 enzyme superfamilies. [254] The use of an N-terminal threonine for proteolysis.
A relationship exists between the anatomy of the stem node and the presence or absence of stipules: most plants with trilacunar nodes have stipules; species with unilacunar nodes lack stipules. [ 3 ] Stipules are morphologically variable and might appear as glands , scales, hairs , spines , or laminar (leaf-like) structures.