What often runs lengthwise separating the theca?

Step-by-step solution

Careful observation of each stamen under a dissecting microscope and making neat diagrams would elucidate the range in shape and attachment of anthers in different flowers. A typical angiosperm anther is bilobed with each lobe having two theca, i.e., they are dithecous Often a longitudinal groove runs lengthwise separating the theca. Let us understand the various types of tissues and their organisation in the transverse section of an anther The bilobed nature of an anther is very distinct in the transverse section