with its finely patterned leaves, are also suitable as indoor pot plants. Unsustainable logging of tropical primary forests is threatening a number of peppers. The extent of the effect of such wholesale habitat destruction on the genus is unknown, but in the forests of Ecuador – the only larger region for which comprehensive data exists – more than a dozen species are known to be on the brink of extinction. On the other hand, other Piper species (e.g. spiked pepper, P. aduncum) have been widely distributed as a result of human activity and are a major invasive species in certain areas. The most significant human use of Piper is not for its looks however, but ultimately for the wide range of powerful secondary compounds found particularly in the fruits. As spice and vegetable Culinary use of pepper plants is attested perhaps as early as 9,000 years ago. Peppercorn remains were found among the food refuse left by Hoabinhian artisans at Spirit Cave, Thailand. It is likely that these plants were collected from the wild rather than deliberately grown. Use of peppercorns as pungent spice is significant on an international scale. By classical antiquity, there was a vigorous trade of spices including black pepper (P. nigrum) from South Asia to Europe. The Apicius, a recipe collection complied about 400 AD, mentions "pepper" as a spice for most main dishes. In the late Roman Empire, black pepper was expensive, but was available readily enough to be used more frequently than salt or sugar. As Europe moved into the Early Middle Ages, trade routes deteriorated and the use of pepper declined somewhat, but peppercorns, storing easily and having a high mass per volume, never ceased to be a profitable trade item. In the Middle Ages, international traders were nicknamed Pfeffersäcke ("pepper-sacks") in German towns of the Hanseatic League and elsewhere. Later, wars were fought by European powers, between themselves and in complex alliances and enmities with Indian Ocean states, in part about control of the supply of spices, perhaps the most archetypal being black pepper fruit. Today, peppercorns of the three preparations (green, white and black) are one of the most widely used spices of plant origin worldwide. Due to the wide distribution of Piper, the fruit of other species are also important spices, many of them internationally. Long pepper (P. longum), is possibly the second-most popular Piper spice internationally; it has a