The milkweed, scientifically known as Euphorbia peplus, is described in the article as a fresh and vibrant plant found throughout the streets of Spain. Its striking green color and unique inflorescences bring a sense of joy and brightness to the urban landscape. The plant thrives in cracks on sidewalks and other urban spaces, illustrating its adaptability and persistence in a human-altered environment.

The article highlights the close relationship between the milkweed and local ants, which play a role in the plant's ecosystem. Despite its beauty, the milkweed is referred to as 'poisonous basil' in some countries due to its toxic properties, which can be hazardous if ingested. This duality of being both aesthetically pleasing and potentially dangerous adds to the intriguing nature of the plant.

Furthermore, the article situates the milkweed within the wider context of the Euphorbia genus, which contains more than 2,100 species. By examining its characteristics and growing habits, the article invites readers to appreciate the subtle beauty and ecological importance of this commonly overlooked flora amidst urban development in Spain.