Tag Archives: kale

Greens: why we eat the leaves that we do

Jeanne reveals which branches of the evolutionary tree of plants bear edible leaves and speculates about why that is.

Giant coconut palm (Cocos nucifera) fronds dwarf me

Giant coconut palm (Cocos nucifera) fronds dwarf me

Most of the 300,000 + plant species have leaves, and the function of all of them is to perform photosynthesis.  They are the ultimate source for all of the oxygen and food for the rest of the food chain and help regulate the global carbon and water cycles.  They are also nutrition superstars.  To figure out why greens are good for you and whether all leaves are equal in this regard, we need to take quick look at global leaf structural variability and broad evolutionary patterns in the species that make their way onto our tables. Continue reading

The extraordinary diversity of Brassica oleracea

Before the caterpillars attacked: Red Russian kale seedlings

Jeanne turns her frustration with caterpillars in her garden into an exploration of the botany behind an extraordinary species:  Brassica oleracea.

White cabbage butterflies (Lepidoptera: Pieris rapae) decimated the fall kale crop in our garden.  To be fair, the abundant green caterpillars did not consume the entire blade of every leaf.  The remaining nibbled leaves, however, in my husband’s view, no longer resembled food so much as a caterpillar farm that would be tedious to turn into food.  He ripped out the caterpillar farm, threw it on the compost bin, and replaced it with lettuce.  Unlike kale, which is in the mustard family (Brassicaceae), lettuce is in the sunflower family (Asteraceae) and is therefore not even remotely attractive to white cabbage butterflies.

Caterpillar damage on young green curly kale in the garden at Monticello

I was tempted to save the hole-riddled leaves from their compost fate, in part because I know that the munching of the caterpillars actually increased the foliar concentration of some of the compounds that contribute to kale’s nutritious reputation, and also because plummeting autumn temperatures impart an extraordinary sweetness to kale and the other cruciferous vegetables that are all actually varieties of the same species, Brassica oleracea: cauliflower, cabbage, kohlrabi, Brussels sprouts, Chinese broccoli, and collard greens.  The details of the chemical consequences of caterpillar consumption will soon get a post all their own.  This post is dedicated to the botany and evolutionary biology behind the amazing diversity of B. oleracea. Continue reading