Noun
English Wikipedia has an article on:phytomelaninWikipedia
phytomelanin (uncountable)
(botany) A hard, black material that forms a crust on the surface of some seeds
The seeds characteristically have the external epidermis either obliterated (in most species bearing fleshy fruit), or if present, have a layer of black carbonaceous phytomelanin in species with dry fruits (nuts). Source: Internet
The inner part of the seed coat is generally collapsed, in contrast to Liliales whose seeds have a well developed outer epidermis, lack phytomelanin, and usually display a cellular inner layer. Source: Internet