MORPHOLOGY OF PLANT VEGETATIVE ORGANS

6. Analogous and homologous plant organs

In The process of adapting to environmental conditions, plants undergo modifications of certain Organs, forming metamorphoses that perform specific Functions atypical of the original organ. At the same time, modified organs may perform the same function while having different evolutionary origins. In this regard, C. Darwin introduced The concepts of ANALOGOUS AND HOMOLOGOUS organ modifications.

Analogous organs are defined as those that perform the same function and have a similar outward appearance, yet differ in origin. Examples of analogous organs include spines and tendrils. In gleditsia, hawthorn, and wild pear, spines are of SHOOT origin; in cacti and barberry, they are of leaf origin; and in black locust (Robinia pseudoacacia), spines are modified stipules. In grapes, tendrils are of shoot origin, whereas in peas and vetch, they are of leaf origin.

Homologous organs are those that share a common origin, but differ in Structure AND FUNCTIONS performed. For example, a potato tuber, a gleditsia spine, an onion bulb, and a grapevine tendril are homologous organs because they are all modified shoots, yet they perform different functions and exhibit distinct structures.



Last update: 07/08/2026

Editorial and Educational Adaptation: This material has been compiled based on the primary/original source text. The project team performed an editorial review, corrected technical inaccuracies, structured sections, and adapted the content for an educational format.

What was processed:

  • elimination of formatting defects (OCR errors, structural breaks, corrupted characters);
  • editorial organization of content;
  • standardization of terminology in accordance with academic sources;
  • verification of factual statements against the original source text.

All mentions of the author, publication year, and origin of the primary text have been preserved in accordance with the source.