A Most Unusual Plant

My garden is arranged in geographic sections. One of those sections is devoted to plants of the Channel Islands, primarily Anacapa, Santa Cruz and Catalina. These island plants are interesting for several reasons. They tend to be a bit more garden-friendly, especially for coastal gardens, because they are more tolerant of supplemental water. Some island plants are exactly the same as their mainland counterparts. Other species have evolved differences from mainland ancestors as a result of their isolation. Still others are truly unique and have no close cousins on the mainland.

On a personal level, I grew up in Ventura and Santa Barbara Counties where I was able to see the islands often. As an adult I had the opportunity to visit Anacapa and Santa Cruz Islands several times. One of the plants I got to know on Anacapa Island was Leptosyne (formerly Coreopsis) gigantea. It's a member of the Asteraceae (sunflower) family, but a really odd one, primarily due to its main stem which is a stout, succulent (not woody) trunk up to 6 ft. high and 3-5 in. in diameter. The trunk can go straight up like the one in the photo, or it could slump to the ground or even twist itself around in a curl. The trunk serves as water storage. A few branches may be produced near the top.

Leaves are produced in a tight cluster at the stem tip. In summer they dry out and hang limply like shaggy hair, as shown above. The next photo shows new leaves emerging right now.

The inflorescence is the typical sunflower type of both disk and ray flowers. The photo below shows a dry seed head. Lots of seeds are produced and they germinate readily, typical of Asteraceae.

The trunks of tall plants like the one in the first photo can break easily, in which case they will sometimes sprout from the top of the stump.

This species grows wild in only one spot on the mainland, on coastal bluffs in the Pt. Mugu part of Ventura County. However, Caltrans has used it in seed mixes for freeway slopes in various spots, so it may be seen in unlikely locations. Thus, it is not native to Encinitas or even San Diego County, but it is doing well in my garden and it is a foundation of the Channel Islands theme.