Daucus carota, budding out.
Don't look like carrots? But they do; like garden carrot plants magnified and gone to seed. These are biennial plants, just like our domestic carrot, which is a subspecies of this ancestor plant. The first year, they produce leaves and roots. The second year (but by then we've harvested and eaten our tame carrots) they produce stems, flowers and seeds. The wild carrots' stems can reach a couple of metres tall or more; we saw one on Reifel a couple of years ago, flowering well over our heads.
"Wild carrot" is too tame a name for it, though, so it has been called Birds Nest Weed, Bishop's Lace, Bees' Nest, and Devil's Plague, depending, I think, on whether the emphasis was on its ability to out-reproduce, out-endure, out-elbow garden plants, or on the beauty of the flower and seed heads. We know it here as Queen Anne's Lace, which suits it. The flower head, or umbel, would make a good pattern for the lace that Queen Anne was accustomed to wearing as a half-collar. (See the series of photos in this Wikipedia article, starting here.)
New flower umbels.
The flower heads start as a disorderly green clump, slightly indented in the centre. As the flowers open, the clump opens out into an umbrella shape, each one made up of many smaller "umbrellas", or umbels.
Small flower head.
Once the flowers are pollinated, the umbrella folds in upon itself again, this time more neatly, making a pretty green cup, or nest, which tightens down until it's almost a ball. When the thousands of seeds ripen (they turn purple, then brown), it opens up again and scatters them far and wide.
The "bird's nest" stage. Last summer.
(Fertile garden carrots do this, too, but the next generation from those seeds will be woodier and less flavourful than the parents. They're reverting back in the direction of the original stock.)
The seed heads often break off, and roll in the wind, spreading seeds as they go. Or the bristly seeds snag passing animals or human clothing and hitchhike to new areas. They'll grow almost anywhere; in disturbed ground, roadsides, clay, open fields, or your carefully-tended vegetable garden. Once it's in the garden, it will take years of constant weeding to eradicate it; then you'll start calling it the Devil's Plague.
It's welcome on Reifel Island. The birds eat the insects they attract, and later on, the seeds. And the other local plants are well-equipped to hold their ground. In the second and third photos above, the leaves of the equally-tough Himalayan blackberry are mingling with the lace leaves. I don't know which will end up in possession of the patch.
Wikipedia, and many other sites, warn us about the danger of mistaking Poison Hemlock for Queen Anne's lace, and they are similar plants. But they are not identical; the Lace has bracts (those spiky collars) around the base of the large flower umbels; hemlock has them only on the upper umbels. The stems and leaves of the Lace are hairy, and it smells like carrots.
I found a site with a beautiful series of photos of Queen Anne's Lace, from macro- to microscopic views. Go see!
*Update and correction: I just found out that my info was correct, but the photos weren't. The photos we have are of cow parsnip, which is similar but not identical. Queen Anne's Lace does grow here, but the leaves are different; they are more carrotty, and don't have those "wraps" on the stems. And it will not grow as tall as the cow parsnip.
I'm not so sure about the last photo. It has the characteristic "bird's nest" shape of Queen Anne's Lace, and was from some shorter plants, I think on the North Shore. The leaves aren't visible, but the sharp bracts at the base of the flower are.
You can compare the two plants on E-Flora BC, here (cow parsnip) and here (Queen Anne's Lace).