Introduction

Angiosperms, the flowering plants, show an enormous range of external form — yet however different two flowering plants may look, each is still built from the same handful of organs: roots, stems, leaves, flowers and fruits. This chapter turns to that external structure, or morphology, in detail.

Earlier chapters looked at how plants are classified on the basis of their morphological and other characteristics. Making sense of that classification — and correctly describing any higher plant, or indeed any living organism — depends on a shared vocabulary of technical terms and precise definitions for each part. It also means recognising how much these parts can vary, since many of the differences seen from one plant to another are adaptations to a particular habitat or role, such as structures modified for climbing, for storing food, or for protection.

This kind of careful, structure-first description has a long tradition in botany. The plant anatomist Katherine Esau (1898-1997) is one of its best-known figures: her research traced how the food-conducting phloem tissue carries plant viruses through the plant body, and her books on plant anatomy, written with a developmental, cause-and-effect approach rather than mere description, reshaped how the internal and external structure of plants is studied and taught. Her career — recognised with election to the National Academy of Sciences and the National Medal of Science — is a reminder that the plant body's structure, the subject of this chapter, is not just a list of parts to memorise but a record of how a plant works.