De Bary's Comparative Anatomy of the Phanerogams and Ferns (1877) supplied an admirable presentation of the facts so far known.
This is the case in the stems of must Phanerogams and of some Pteridophytes.
The flower is a characteristic feature of the highest group of the plant kingdom - the flowering plants (Phanerogams) - and is the name given to the association of organs, more or less leaf-like in form, which are concerned with the production of the fruit or seed.
The Gymnosperms, with the Angiosperms, constitute the existing groups of seed-bearing plants or Phanerogams: the importance of the seed as a distinguishing feature in the plant kingdom may be emphasized by the use of the designation Spermophyta for these two groups, in contrast to the Pteridophyta and Bryophyta in which true seeds are unknown.
Leguminosae, the two most numerous orders of phanerogams, but in number of individual plants it probably far exceeds either; whilst from the wide extension of many of its species, the proportion of Gramineae to other orders in the various floras of the world is much higher than its number of species would lead one to expect.