Dear Twig: What's the glop inside pumpkins called? Well, Iâve always called it glop, too. But I checked with my scientist friends and they told me the technical term is âendosperm.â Endosperm is the flesh around fruit seeds. What does that mean? It means that a pumpkin is a fruit. Yep! Specifically, itâs a type of fruit called a pepo (âpee-poeâ). Pepoes are fleshy with a hard rind and many seeds, which, if you add âorange,â describes a pumpkin to a T. The part of the rind that you cut through when carving a jack oâ lantern is the mesocarp. The inner part of the rind is the endocarp. The endocarp is where the seeds and the endosperm are produced. Juice is made here, too. The juice makes things slimy. The slime makes things gloppy. The result is sticky fingers. What does endosperm actually do? It might protect and nourish the seeds, an important job. And it might make the fruit more attractive to animals, who, in eating the fruit, help spread the seeds around. Not all pumpkins are gloppy inside. Ripe ones are pretty dry. And some varieties are gloppier than others. How do you know which is which, since all of them are orange? Cut one open and reach inside. If the sound you hear is âsplortâ youâll know! Twig Hey Editor! Bob Precheur, associate professor, and Matt Kleinhenz, assistant professor, Department of Horticulture and Crop Science, Ohio State University, provided information for and reviewed this column. "Smart Stuff with Twig Walkingstick," a service of The Ohio State University College of Food, Agricultural, and Environmental Sciences, is a weekly science column for kids. "Twig" is a bow tie-wearing cartoon walkingstick, a type of insect. He's the voice of the column and appears at the left in the hard-copy version. "Bob the Bug," Twig's pal, is a bald-headed bug of an unidentified type who doesn't say much and appears in the bottom-right corner. For more information or to receive "Twig" columns by mail or e-mail, contact Kurt Knebusch, 1680 Madison Ave., Wooster, OH 44691, (330) 263-3776, email@example.com.