Pulcinculo is one of the names you may come across for the grape variety Pignoletto, a white wine grape with roots in northern Italy's Emilia-Romagna. Here it belongs in particular to the hills around Bologna in the part of the region called Emilia, where it features, among other things, in DOC categories such as Colli Bolognesi. The variety was historically also cultivated in Romagna, but is rare there today, even though it appears in appellations like Colli di Rimini. In fact, the grape was first described precisely in the landscape around Rimini, all the way back in 1876.
One of the more confusing aspects of Pignoletto is its many names. Genetically, the grape is identical to Grechetto di Todi, and it is worth being precise about that full name. Grechetto di Todi is a particular biotype and therefore not the same as Grechetto in the broad sense. That explains why you find the grape further south under that name, primarily in Umbria, where it forms an important component in the classic Orvieto blends. To a more limited extent it is also cultivated in Marche and Lazio.
Pignoletto produces white wine, and the variety exists in several clones, including CAB 3, CAB 5, VCR 3 and ICA PG. The latter is known for its good resistance to fungal diseases such as powdery mildew and grey mould, but can on the other hand lose acidity quickly if the grapes become overripe. This applies especially to tartaric acid in warm and humid vintages, which underlines how much timing in the vineyard means for the freshness that characterises the variety.
If you want to understand Pulcinculo, it is therefore two worlds that meet. On the one hand Emilia-Romagna's home ground, where the grape is a local classic, and on the other hand Umbria, where as Grechetto di Todi it plays a central role in Orvieto. It is a grape that rewards curiosity, and that gives you a good insight into how a single genetic starting point can have several identities across the Italian regions.