THE ROLE OF EMBRYOLOGY IN PLANT TAXONOMY
Taxonomy is a branch of biological science which includes identification, Classification, and nomenclature of organisms. So, taxonomy is the lawful arrangement process of the living organisms.
Embryology is the study of structure and development of embryo, including the structure & development of male and female reproductive organs, fertilization and similar Other processes.
The role of embryology in solving taxonomic problems was first brought into prominence by a German Embryologist Schnarf in 1931.
BASIC EMBRYOLOGICAL CHARACTERS THAT USED TO SOLVING TAXONOMIC PROBLEMS :
According to Maheshwari, Bhojwani and Bhatnagar and Radford, some of these basic embryological characters, which have proved to be of special importance in taxonomic considerations include:
(i) Presence and type of anther tapetum, whether glandular or amoeboid.
(ii) Number and arrangement of anther loculi.
(iv) The arrangement of pollen tetrads after microsporogenesis - tetrahedral, isobilateral, linear, T-shaped or otherwise. 
(v) Development and organization of the pollen grains i.e., number and position of germ pores, exine stratification, number of cells at the time of anthesis, etc.
(vi) Development, structure, position, orientation of ovules.
(vii) Types of ovules.
(viii) Development of embryo sac.
(ix) Types of embryo sac.
(x) Number and distribution of nuclei inside the embryo sac.
(xi) Presence and absence of endosperm haustoria.
(xii) Growth and entry of Pollen tube into the embryo sac.
(xiii) Type of endosperm i.e., whether nuclear, cellular or helobial type.
(xiv) Nature of seed-coat.
(xv) Types of Fruits
APPLICATION OF EMBRYOLOGICAL DATA IN PLANT TAXONOMY :
1. Dicot & Monocot Plants –
Angiosperms are universally divided into dicotyledons and Monocotyledons. The primary classification of angiosperm is based on one major embryological character I.e; the number of cotyledons.
2. Helobiae –
This monocotyledonous order, treated as a subclass in some recent system of classification, is characterized by the presence of a helobial type of endosperm.
3. Orchidales –
This order is characterized by the presence of undifferentiated embryo and very little or no endosperm. 
4. Polygonales and Plumbaginales –
They are related to each other, and are also clearly related to Caryophyllales as they exhibit similar embryological features to a great extent.
5. Lecythidales –
This order, which was formerly considered, to be related to Myrtales, has been found to differ from the latter by the presence of alternate leaves, centrifugal stamens, lack of internal phloem and a series of embryological features in its various members.
6. Lemnaceae: Phylogenetic studies indicate that Lemnaceae have been derived either from the Helobiales or from the Araceae. But on the basis of the embryological studies, Maheswari suggested that Lamnaceae have been evolved from Araceae, not from Helobiales.
7. Crassulaceae: Embryological studies of Crassulaceae suggest that it should be placed in the order Rosales.
8. Peganum –
This genus has been variously treated as a member of Rutaceae or Zygophyllaceae. But its embryological details resemble those of Linaceae, and differs from those of Rutaceae and Zygophyllaceae. The recent embryological findings, therefore, suggest its inclusion in an independent family, Peganaceae near Linaceae.
9. Butomus –
Butomus of the family Butomaceae is characterized by the presence of the Polygonum type of embryo sac, while all the other genera under this family have the Allium type of embryo sac. This suggests that only Butomus should be retained in Butomaceae.
The other genera of this family should be transferred either to Alismataceae or to Limnocharitaceae. Cronquist and Takhtajan also retained only Butomus under Butomaceae and transferred the remaining genera to Limnocharitaceae.
10. Genus, Trapa –
*Some have placed it under Onagraceae
*Some have placed it as an isolated member of Haloragaceae, and
*Some have placed it as the only genus of the monotypic family Trapaceae.
Embryological evidence however strongly supports the last view. Trapa has a well- developed suspensor haustorium, in addition to the eight-nucleate embryo sac, which are absent in any other members of Onagraceae.
In Trapa, the ovary is semi-inferior, bilocular with one ovule in each locule and the fruit is a large one-seeded drupe, while in other members of Onagraceae, the ovary is inferior and tetralocular with numerous ovules on axile placentation and fruit is generally a loculicidal capsule.
