Teosinte

• Teosinte plants are branched and produce many ears
• In teosinte, the leaves along the lateral branches are fully formed and composed of two parts —the sheath that clasps the stem and a well-developed blade that extends away from the stem. 
• Teosinte ear possesses about 5 to 12 kernels, each sealed tightly in a stony casing (fruitcase).
• Teosinte kernels can survive the digestive tracts of birds and animals (Wilkes, 1967).
• At maturity, the teosinte ear disarticulates and individual fruitcases become the dispersal units.
• Teosinte cupule is formed from an invaginated rachis segment (internode) and a glume (modified bract) that covers over the kernel sitting in the cupuleIn teosinte, the cupulate fruitcases are borne in two ranks on opposite sides of the longitudinal axis of the ear.
  • Each cupulate fruitcase holds a single-spikelet (kernel-bearing structure). Early in teosinte ear development, there are two spikelet primordia on each rachis segment; however, one is aborted early.
• In teosinte plants, each primary lateral branch is elongate and bears a tassel at its tip.
• In teosinte, there are secondary (and higher-order) lateral branches that are terminated by ears, each ear surrounded by a single husk.
• Terminal position of primary branch bears a tassel

Maize

• Maize plants produce a single upright stem with ears.
• In maize, blade of the lateral branch is small (or missing) and the sheath (husk) clasps around the ear rather than the stem per se, since the internodes of the branch are much shorter than in teosinte.
  • Maize ear can bear 500 or more kernels, each is attached to the central axis of the ear or cob.
  • The kernels are naked without adequate protection from predation and are easily digested by any animal that consumes them.
  • At maturity ear does not disarticulate. Whole cob falls on ground and several seedlings germinate and do not get proper nutrition. Hence dependent upon humans for survival.
  • The cupule and glume in maize are reduced in size and do not surround the kernel but form the cob. Thus, in maize rachis segments and glumes formed a cob rather than fruitcases
  • In maize, there are two mature spikelets (kernels) on each cupule because the one aborted in teosinte develops to maturity in maize. Thus, maize evolution involved the derepression of the second spikelet primordium.
  • In maize, the cupules are borne in four (or more) ranks. Thus, maize evolution involved a switch from two to four ranks of cupules.
  • In maize, each lateral branch is short and has an ear at its tip
  • In maize, secondary lateral branches terminated by ears are uncommon.
  • Terminal position of primary branch of maize bears ear