The most important flower and leaf use in the worship and puja of Hanuman is Arka leaves.
Arka in various languages:
English: Bowstring Hemp, Calotrope, Crown Flower, Giant Milkweed, Swallow-Wort
Hindi: Ak, Akua, Arka, Akwan, Fudhar, Madar, Safed Aak
Marathi: Arka, Arki, Rui, Ruiti
Sanskrit: Alarka, Arka, Arki, Sadapushpa
Tamil: Erukku, Malaiyerukku