This lovely little yellow flower is Eranthis hyemalis, more commonly known as the winter aconite. Native to the woodlands of continental Europe, the winter aconite is a member of the sprawling & poisonous buttercup family (which includes beauties and horrors like the monkshood, the ranunculus, and the delphiniums). Eranthis hyemalis which is now blooming here in New York (in gardens which are eccentric enough to have it) is a quintessential spring ephemeral—it blossoms and grows in earliest spring before any trees are in leaf—or even in bloom. The plant flowers and puts out leaves and gathers sunlight and stores energy all before the other plants even start. Then, as the woodland canopy expands above it and as its growing spot is covered with shade, the aconite dies back to its hardy underground tuber which remains dormant until next spring. Although it lives in verdant forests it could almost be an ascetic desert flower based on its hardiness and hermit-like lifestyle. It would be a big mistake to mistake the flower for a weakling or a vegetable–like the other buttercups, all parts of it are ferociously poisonous. Do not eat it (or smoke it…or even look at it funny)!