• Theca are separated by a longitudinal groove running lengthwise. explain please

Thecae are locules of anther, each containing two microsporangia. Anther is dithecous and the two thecae are separated by a column of sterile tissues (connective tissues), running lengthwise which is externally visible as deep longitudinal groove (narrow cut or depression). These types of partition also exist between sporangia in a theca.