Winter is the season for citrus fruit, and January is the month for breaking out of old routines, so stop staring at your navel and learn about one of the weirder citrus varieties.
I’ll never forget the day one of my general botany students brought to class a Buddha’s hand citron, pulled from a tree right outside our classroom. I had only recently moved to northern California from Indiana, and I’d never seen anything like it: it was a monstrous mass of a dozen pointed twisted fingers splayed irregularly from a stout base. It had the firm heft and girth of a grapefruit and the unmistakable pebbled skin of a citrus fruit, so I wondered whether my student had found a grossly deformed grapefruit; but the oil in the peel smelled heavenly and not at all like a grapefruit. In class we cut through a big finger and found no juicy segments, just white citrus pith all the way through.
Immature Buddha’s hand on the tree
We eventually discovered that this fascinating fruit was a Buddha’s hand citron, Citrus medica variety sarcodactylis, meaning fleshy (sarco-) fingered (-dactyl) citron. Since that day many years ago I’ve become an unapologetic (if surreptitious) collector of the fruits from that same campus tree. The citrons do not drop from the tree on their own, yet I often find one or two lying nearby, probably torn off by a curious tourist or student and then abandoned. Obviously these fruits need a good home, and where better than the window sill in my office?
The first time I left one closed up in my office over a weekend, I opened the door on Monday morning to a waft of fruity floral aroma. It turns out that many people in China and India use the fruit to scent the air, although in west Asia and Europe the fleshy fingers are more often candied or used to flavor alcohol. I do both: the fruits make my office smell nice until they are fully yellow, and then I cook them.
It can be difficult or expensive to get your own hands on a fingered citron, but it’s easy to find a navel orange almost any time of the year. Fortunately, the patterns underlying the morphology of the fingered fruit can also be seen in an everyday navel orange. Between our photos of Buddha’s hands and your own navel orange, you should be able to follow along at home.Continue reading →
Yerba maté, the popular herbal tea from South America, is a species of holly. It’s also caffeinated, a characteristic shared by only a small number of other plants.
English holly. Photo by K. Bills
Along with conifer trees and mistletoe, hollies are a botanical hallmark of the winter holiday season in Europe and the United States. Most hollies are dense evergreen shrubs or small trees and produce beautiful red fruits that stay on the plant through the cold winter months. Sprays of the dark green foliage grace festive decorations, and wild and cultivated hollies punctuate spare winter landscapes. Especially popular in winter, too, are warm beverages. One of the most popular, at least in South America but increasingly elsewhere, is yerba maté. It is a seasonally appropriate choice because the maté plant is a holly. Unlike the decorative hollies, usually American (Ilex opaca) or English (Ilex aquifolium) holly, maté (Ilex paraguariensis) is caffeinated. This puts it in rare company, not only among hollies, but among all plants. Continue reading →
A batch of lemon balm-lemon verbena syrup reminds Jeanne of the multiple evolutionary origins of lemon flavor.
The citrus lemon itself is only one of many plant species that lends its namesake flavor or fragrance to our food and drinks. Lemon flavor primarily comes from a few terpenoid essential oils: citral (also called geranial, neral, or lemonal), linalool, limonene, geraniol, and citronellal. The production of one or more of these essential oils has independently evolved multiple times in species on widely separated branches of the plant phylogeny (see figure).
Phylogeny of plant taxonomic orders with edibles (click the tree to enlarge). Orders with species with lemony essential oils are highlighted in red. For a refresher on reading this phylogeny, please see our food plant tree of life page.