Conium maculatum (Poison Hemlock)
Image credit: Matthew T RaderIdentification tips
Tip #1: the name of the genus Conium comes from the Greek "hemlock". This may be related to konas (which means spinning), in reference to vertigo, one of the symptoms of plant ingestion. maculatum comes from Latin and has a relationship with spotting or stained, a feature that greatly facilitates the identification of the species is its stained stem.
Plant shape
2º Identification tip: the plant is a herbaceous, has slow initial growth, in the second year of life it tends to grow faster and vigorously.
Leaves
3º Identification tip: the leaves are bright greens, similar to ferns, thinly divided, toothed on the edges and have a strong moldy odor when crushed.
Stem
4º Identification tip: the stem has reddish or purple spots and streaks, are not hairy and are hollow.
Flowers
5º Identification tip: the flowers are tiny, white and arranged in small umbrella-shaped curls at the ends of the branched stems.
Seeds
6º Identification tip: the seeds are half moon shaped, have five protrusions,highlighted forming veins in the seeds. For those who want to properly identify the seeds of a look at this link.
Seedlings - the terror of all
7º Identification tip: seedlings have the cotyledonary leaves in the form of a spatula and have veins of dark green coloration, the first true leaves already have the rendered shape, characteristic of the leaves of the species.
Extra references:
https://www.illinoiswildflowers.info/weeds/plants/poison_hemlock.htm