The hibiscus, especially Hibiscus rosa-sinensis, the Chinese hibiscus, is a tropical shrub of large, brilliant, short-lived trumpet flowers, most strikingly a deep scarlet. In Hindu worship the red hibiscus holds a special place: it is the flower above all offered to the goddess Kali, the fierce dark aspect of the Divine Mother, and to Ganesha, its blazing red answering to Kali's power and to the colour of blood and life. Garlands of hibiscus are laid before her images, and the flower is bound up with the worship of the goddess in her most intense forms.
A different hibiscus species, Hibiscus sabdariffa, or roselle, is grown across the tropics specifically for its tart, deep-red calyces, brewed into the drink known as karkade in Egypt and Sudan, agua de jamaica in Mexico and bissap in West Africa, a beverage tradition entirely separate from the ornamental red hibiscus offered to Kali. Several modern clinical trials have examined hibiscus tea for its effect on blood pressure and found a modest reduction in some studies, one of the more genuinely evidence-supported traditional beverage claims in this atlas, though it is not a substitute for prescribed treatment of high blood pressure.