ABSTRACT
Nucellus (Latin nucellus)—a major ovular structure wherein initiation and development of sporogenous cells and female gametophyte occurs. Synonyms: megasporangium, macrosporangium (Plate 38). Brown (1826b) established the presence in the ovule of a central body, or 'nucleus' (core), and integuments. Mirbel (1829) was the first to apply the term 'nucellus' (French nucelle) to the central part of the ovule. Hofmeister (1851) convincingly demonstrated the nucellus of angiospermous ovule to be homologous to the megasporangium of other higher plants. This assumption was supported by some outstanding botanists (Warming, 1878; Schnarf, 1929; Takhtajan, 1964,1980b; and others). Aspects of nucellus genesis were described for the first time by Warming (1878) in his seminal paper 'De l'ovule', based on results of studies of a great number of plant species.
