caducous
adjective
ca·du·cous kə-ˈdü-kəs 
-ˈdyü-
: falling off easily or before the usual time —used especially of floral organs
Word History
Etymology
Latin cadūcus "on the verge of collapsing, ready to fall (of fruit), transitory" (from cadere "to fall" + -ūcus "performing the action [of the verb specified]") + -ous — more at chance entry 1
First Known Use
1775, in the meaning defined above