The Pipestem Clematis (Clematis lasiantha) is a creamy-white flowering liana, belonging to subgenus Clematis of the large Clematis genus. It is found on the Pacific coast of North America, from the San Francisco Bay Area southwards into Baja California. It extends as far east as the western foothills of the Sierra Nevada mountains, but does not grow in the Central Valley, nor at heights greater than about 2000 metres. It grows on hillsides, in chaparral, and in open woodland.
The Pipestem Clematis flowers from January to June. Its leaves are 3-lobed, and generally grow groups of three to five leaflets, the largest leaves on the plant normally being between 3 and 5 cm in size. The Pipestem Clematis can be distinguished from the similar (but much more widely ranging) Virgin's Bower (Clematis ligusticifolia) by the fact that Pipestems normally only have one flower on each stalk, and at most three, whereas the Virgin's Bower has multiple flowers on each stem. The Pipestem also has more pistils in each flower, but since both species have many, this is not an easy criterion to apply. The Virgin's Bower is more likely to be found along streams or in other wet places, whereas the Pipestem tolerates more open, drier places.