Tuesday, February 26, 2008

Burger's Onion

The genus Conophytum comprises about 100 species of compact succulents (or “sphaeroids”) in the mesemb family (Aizoaceae), native to dry areas in South Africa and Namibia. Possibly because the plants tend to be slow growing and a bit finicky in cultivation, “conos” are never available from The Home Depot or local nurseries, where one can often find their cousins, Lithops, for sale. Conos aren’t much known at the species level even among succulent plant enthusiasts, except by specialists (such as me; I wrote a dissertation on the little guys), and so far as I’m aware, only one species has ever earned itself a widely known common name: Conophytum burgeri, a.k.a. Burger’s Onion.

Conophytum burgeri is an oddity among oddities. Plants of the species consist of rounded conical masses of translucent, gelatinous tissue (actually a fused pair of succulent leaves), colored pink, reddish, and green, attached to a shallow root system. One rarely sees the gumdrop-like plant body itself, however, because it hides inside of a sheath—like the skin of an onion—composed of the papery remains of leaves from past years. Burger’s Onion can grow to be the size of the pointed half of an egg, but that takes a decade or longer.

Conophytum burgeri in cultivation at the University of Connecticut, October 2007.

Burger’s Onion grows naturally on a patch of white and rose quartz pebbles, outside of the mining town of Aggeneys, in Bushmanland in northwestern South Africa. The pale sheathing that surrounds the plants blends in with the pebbles, and undoubtedly reflects excess light and slows water loss. Seedlings, which start out smaller than pinheads, actually germinate underneath bits of quartz, which apparently allows in enough light to support growth, while shielding the delicate young plants from the harsh Bushmanland climate. This sort of behavior has been reported from time to time for C. burgeri and other sphaeroid mesembs from arid quartz fields, but I almost didn’t believe the reports until I witnessed it in person while gently turning over bits of rock on a visit to Aggeneys in August of 2000.

Aggeneys (pronounced something like Ahk-ken-ays, to the ears of this Afrikaans language poseur) is one of the driest corners of a dry country. Regional natural history expert Irma Burger (daughter-in-law of Abraham Burger, after whom the onion is named), grew up in the area, and tells me that there was a stretch of several years when she never saw rain. Showers and thunderstorms are rare and scattered, occurring mostly in summer. Burger’s Onion tends to be active in winter, when cooler temperatures and shallow moistening of the soil from dew apparently create the most favorable conditions for growth.

The native range of C. burgeri is literally the size of a couple of tennis courts; fortunately it seems to be situated away from mineral resources that might inspire digging and blasting, yet well within mining company territory that is fenced off, with locked gates that exclude the elsewhere all-too-common enemies of delicate dwarf succulents: goats, sheep, unscrupulous collectors and drunks with 4X4s. The mining company is also responsible for coining, or at least popularizing, the name Burger’s Onion: years ago, the mine used the plant as the subject for a poster in an environmental awareness campaign.

Next month, I’ll write a bit about growing Conophytum burgeri in New England. It’s doable, but not exactly easy.

Monday, February 18, 2008


Last year, I was elected/conscripted to be vice president of the Connecticut Cactus and Succulent Society, a fine organization which everyone living in southern New England, with an interest in desert plants, should join. As part of my duties, I've taken to writing a monthly column for the CCSS newsletter. The newsletters are available to download as PDFs at the CCSS website, but I thought it might be useful to post some of my more general-interest columns in a more accessible format.

The backbone of this blog will be my newsletter writings, possibly padded out with extra text or photos that didn't make the cut for the newsletter itself. So, while it won't be worth checking every day, there should be new material here at the beginning of each month, at least. In addition, I'll probably have a random post now and then dealing with other botanical topics, when the urge strikes to write something that doesn't fit in with the contents of a cactus club newsletter.

I'll try to keep the jargon to a level suitable for the amateur grower or armchair botanist, but there may be occasional outbursts dealing with the evolution and epidermal micromorphology of the Mesembryanthemoideae, or some such. Overall, though, Burger's Onion should be accessible to the interested layman. Welcome!