In the inner part of Osafjorden, the mountainside plunges nearly a thousand metres right into the fjord. The narrowness of the fjord makes the plunge extra dramatic. There is not really room for stable sediments on the steep slope, since the landscape is dominated by bare rock faces and rock slides. Under such conditions it is difficult for the forest to get a foothold. Therefore, the sun gets good access to the ground. Because the fjord sides face south and south-east in an area with a warmer summer climate than is usual for these parts, it is both warm and dry on these slopes. Therefore, a number of warm-loving plants that are usually found in eastern Norway thrive here. Almost no other place in the county has so much wild marjoram (left), sticky catchfly, dark mullein (right) and other species associated with dry slopes and outcrops. The best time to see this flora is in early summer, before the middle of July. Then, they decorate the roadsides of Osa. By late summer the plants have probably withered, especially in dry years.