The evolutionary botany is the branch of botany that studies the evolution of plants trying to understand how the present diversity has arisen over time. This branch includes the study of change and subsequent genetic variation that can result in the formation of new species .

The synthetic theory of evolution was conceived during the years 30 and 40 of the twentieth century thanks to the contribution of tests and methods of mathematicians, geneticists, paleobiologists and naturalists. Genetic tests that determined the inheritance of traits were published much earlier by Gregor Mendel (1866) in his famous study of peas , ber Versuche Plflanzenhybriden ("Experiments on plant hybridization." 1 However, as has happened before in history of science, Mendel's Laws did not reach the scientific community until its rediscovery by three botanists: Hugo de Vries , Carl Correns , Erich von Tschermak in 1900 and translated into English in 1901.
Despite being just a plant geneticist Mendel were the scholars who interpreted the animals quickly and applied the results to the animal world. This new body of doctrine soon caught on among zoologists interested in variation and natural selection , so that during most of the twentieth century any textbook on evolution had a large number of examples from the animal world, while examples the plant world were much more limited. However, thanks to the publications of George Ledyard Stebbins (1950), Cyril Dean Darlington (1950) and Verne Grant (1963, 1971), among others, became known evolutionary mechanisms much more common in plants. A list of the most important works in the field of evolutionary botany provided below: 2
(1866) Gregor Mendel, ber Versuche Plflanzenhybriden .
(1937) Theodosius Dobzhansky, Genetics and the Origin of Species .
(1950) George Ledyard Stebbins, Variation and Evolution in Plants .
(1950) Cyril Dean Darlington and K. Mather. Genes, Plants, and People .
(1951) CLAUSEN, J. Stages in Evolution of Plant Species .
(1952) Wardlaw, CW Phylogeny and Morphogenesis .
(1953) Heslop-Harrison, J. New Concept in Flowering Plant Taxonomy .
(1955) CAIN, SA Foundations of Plant Geography .
(1956) GOOD, R. Features of Evolution in the Flowering plants .
(1963) GRANT, V. The Origin of Adaptations .
(1971) GRANT, V. Plant Speciation .

The bract , a term used in botany and introduced by Carl Linnaeus , is the body foliaceus in the vicinity of the flowers and different normal leaves and parts of perianth .
Despite being green, its main function is photosynthesis but to protect the flowers or inflorescences.
Are usually smaller than normal leaves and in some cases, as in the lime , are larger than the flower. In other cases, as in Compositae ( Asteraceae ), are very small, as for example in the bracts of dandelion ( Taraxacum officinale ) can be seen in the picture.

In botany , called braquiblasto a very short stem, defined growth and very short internodes. The flower of the angiosperms , for example, is a leading braquiblasto typical individual parts of a flower: sepals , petals , stamens and carpels . The pines and cedars , on the other hand, have their leaves , in varying numbers, embedded in brachyblast, which then are divided into the branches or stems.

The bulbs , as well as rhizomes , corms and tubers are underground storage organs of nutrients . Plants with this type of structures are collectively known bulbous plants .
The bulb is formed by thickening of the base of the leaves and consists of 5 main parts:
The basal plate is the bottom of the bulb from which to grow roots .
The cataphylls or scales, fleshy , which are the main storage organ, and in their parenchymatous tissue is where nutrients accumulate.
The tunic is a layer that surrounds and protects the scales from drying out.
The stem , which consists of a flower bud and other developing buds.
Buds lateral , which during the period of growth give rise to new bulbs, called bulbils.
The bulbs are classified into two types, tunicates , in which their bases are surrounded by layers, like onions , and scaly , in which the databases are interlinked (like shingles on a roof) and are more fleshy. Both types produce bulbils used to reproduce plants, once they have reached sufficient size. Among the tunicate bulbs include tulips (tulip), the daffodil ( Narcissus ), the hyacinth ( Hyacinthus ), the muscari ( Muscari ) , the onion and garlic ornamental ( Allium ). An example of imbricate bulb is the lily ( Lilium .) The bulb has no lap robe that protects the fleshy scales.

Some of the genera of plants that form bulbs are:
Allium
Amaryllis
Camasia
Chionodoxa
Crinum
Erythronium
Eucharis
Fritillaria
Galanthus
Galtonia
Haemanthus
Hippeastrum
Hyacinthus
Hymenocallis
Leucojum
Lilium
Lycoris
Muscari
Narcissus
Nerine
Oxalis
Polyanthes
Scilla
Tigridia
Tulipa
Veltheimia
Zephyranthes
Some orchids, epiphytes are bodies similar to the bulbs, not underground, called pseudobulbs .






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