Complex sentence: The names of many of these vineyards do not appear on wine labels because of an INAO allowance that permits the use of "umbrella names"-where smaller, lesser known vineyards are allowed to use the name of a nearby more famous Premier cru vineyard.
Split into simpler sentences: The names of many of these vineyards do not appear on wine labels. An INAO allowance permits the use of "umbrella names": in other words smaller, lesser known vineyards are allowed to use the name of a nearby more famous Premier Cru vineyard.