<P> The true fruit of the cashew tree is a kidney or boxing - glove shaped drupe that grows at the end of the cashew apple . The drupe develops first on the tree , and then the pedicel expands to become the cashew apple . Within the true fruit is a single seed , which is often considered a nut , in the culinary sense . The seed is surrounded by a double shell containing an allergenic phenolic resin , anacardic acid , a potent skin irritant chemically related to the better - known allergenic oil urushiol which is also a toxin found in the related poison ivy . Properly roasting cashews destroys the toxin , but it must be done outdoors as the smoke ( not unlike that from burning poison ivy ) contains urushiol droplets which can cause severe , sometimes life - threatening , reactions by irritating the lungs . People who are allergic to cashew ( or poison ivy ) urushiols may cross-react to mango or pistachio which are also in the Anacardiaceae family . Some people are allergic to cashews , but cashews are a less frequent allergen than tree nuts or peanuts . </P>
<P> The true fruit of the cashew tree is a kidney or boxing - glove shaped drupe that grows at the end of the cashew apple . The drupe develops first on the tree , and then the pedicel expands to become the cashew apple . Within the true fruit is a single seed , which is often considered a nut , in the culinary sense . The seed is surrounded by a double shell containing an allergenic phenolic resin , anacardic acid , a potent skin irritant chemically related to the better - known allergenic oil urushiol which is also a toxin found in the related poison ivy . Properly roasting cashews destroys the toxin , but it must be done outdoors as the smoke ( not unlike that from burning poison ivy ) contains urushiol droplets which can cause severe , sometimes life - threatening , reactions by irritating the lungs . People who are allergic to cashew ( or poison ivy ) urushiols may cross-react to mango or pistachio which are also in the Anacardiaceae family . Some people are allergic to cashews , but cashews are a less frequent allergen than tree nuts or peanuts . </P>
what part of the plant is a cashew
what part of the plant is a cashew
seed
seed