Earlier this year I planted some Shanghai Green Pac Choy (Brassica rapa var. chinensis) seeds in a container outside. I harvested and ate them as they became ready, and they were delicious. However, I was a little slow at harvesting one of them and it began to bolt. I decided to go ahead and let it bloom so that I could admire its flowers and possibly collect its seeds. Unfortunately, seed collecting may be out of the question because, even though the flowers on this species are perfect (having both male and female parts), the plants may be self-sterile, meaning I would need a second plant for cross-pollination in order to get viable seed. We’ll see.
Pac Choy is in the Mustard Family (Brassicaceae), which is a relatively easy family to identify. The flowers have four petals and six stamens, and the four petals form a cross, which explains the old family name, Cruciferae. The inflorescence is a raceme, and the fruits are capsules called siliques or silicles. The walls of the capsules dry and break away to reveal the seeds of the fruit housed in a translucent sheet. There are several species in the mustard family that are common vegetable crops, including radish (Raphnus), turnip (Brassica spp.), horseradish (Armoracia), and cabbage, cauliflower, kohlrabi, Brussels sprouts, broccoli, and kale, which are all cultivars of the same species, Brassica oleracea. There are also several annual and biennial weeds in the mustard family, as well as a very common ornamental flower, sweet alyssum (Lobularia maritima).