Orchid flowers (Angraecum comorense). Angraecum orchids are tropical orchids that have green and white flowers. They have a complex structure with pointed sepals (green), petals (white) and a spur (a long tubular extension that usually contains nectar). The spurs are seen running downwards from the base of the flowers. The flowers are growing from a vine (horizontal). These orchids are found in Africa, Madagascar and the surrounding islands, including the Comoros Islands. There are more than 30,000 species of orchids worldwide, many of which are grown as ornamental flowers.