the fruits of the juglandaceae are often confused with drupes but are accessory fruit because the outer covering of the fruit is technically an involucre and thus not morphologically part of the carpel; this means it cannot be a drupe but is instead a drupe-like nut. these odd nuts fall into two different types: in the walnut genus (juglans), it is a pseudodrupe and in the hickory genus (carya), it is a tryma.