Who discovered Glyoxysomes?

Hint: A peroxisome (formerly known as a microbody) is a membrane-bound organelle found in the cytoplasm of virtually all eukaryotic cells. Peroxisomes are oxidative organelles. Molecular oxygen is frequently used as a co-substrate, followed by the formation of hydrogen peroxide. Glyoxysomes are specialized peroxisomes found in filamentous fungi and plant cells.

Complete Answer:
The discovery of glyoxysomes: the work of Harry Beevers in 1961. Glyoxysomes were discovered by Beevers and Breidenbach. Bill Breidenbach was Beevers’ postdoctoral fellow, he demonstrated that the enzymes for the glyoxylate cycle were found during a separate organelle, which they named as glyoxysomes.
Glyoxysomes are specialized peroxisomes found in plants (particularly within the fat storage tissues of germinating seeds) and also in filamentous fungi. Nucleus, plastids and mitochondria are bounded by a double membrane whereas lysosomes, sphaerosome, and glyoxysomes are bounded by one membrane.
Glyoxysomes are the microbodies that contain enzymes for the beta-oxidation of fatty acids and glyoxylate pathways. So, glyoxysomes are found within the endosperm of castor because it contains oil. In castor seeds, endosperm persists within the mature seed and may be used during seed germination.
Glyoxysomes are peroxisomes that contain the enzymes of the glyoxylate pathway additionally to flavine oxidases and catalase. Peroxisomes or glyoxysomes are found altogether in major groups of eukaryotic organisms including yeasts, fungi, protozoa, plants and animals.

Thus, Harry Beevers discovered Glyoxysomes.

Note:
Glyoxysomes are transient in the sense that they appear during brief periods in a plant's life cycle, such as when certain beans and nuts store fats in their seeds as energy reserves. Glyoxysomes appear in endosperm cells a few days after seed germination and are closely associated with lipid bodies.