Ambrosia artemisiifolia

Ambrosia artemisiifolia

Ambrosia artemisiifolia or comon ragweed is the most widespread species of Ambrosia. I have already written about silver burr ragweed (Ambrosia chamissonis). Indeed you can see close resemblance between two different species of the same genus Ambrosia. The leaves look very similar and the tassels of flowers are common to both. But Ambrosia chamissonis grows mainly on the sea coast while Ambrosia artemisiifolia is common on the dry land. It does not mind the hot climate. Beach variety is also more prostrate while common ragweed plants grow tall.

Common ragweed flowers

The name artemisiifolia is given to the plant because the leaves resemble those of a related genus Artemisia (wormwood or sagebrush). The smell is also somewhat similar though Ambrosia have tougher leaves and bigger flowers (still very small though) that are green or yellow. An interesting thing about common ragweed is that it is supposed to be one of the major culprits of hay fever though I personally never suffered from this particular plant.

Like Artemisia, Ambrosia belongs to the Aster family (Asteraceae).

Ambrosia chamissonis

 Ambrosia chamissonis growing among the dunes

Ambrosia chamissonis (silver beach ragweed) is a plant that I have just recently discovered in our dunes. At first I though it was some kind of chenopodium: the triangular shape of leaves and striped stem led me to this opinion. However I quickly found out that it was Ambrosia or beach ragweed, a member of the Aster family (Asteraceae).

Ambrosia chamissonis leaves

So what's up with this plant who is masquerading as chenopodium when in fact it is an aster? It has leaves that can have different shapes: oval or deeply lobed. The leaves are fleshy but not quite as fleshy as those of succulents. The flowers are in a spike. The stems can be very hairy or just barely. Yet it has some kind of integral appearance and once you know it, it is easy to recognize. I guessed it was the same plant in spite of different shape of the leaves. The fruit is supposed to form a burr but I have not seen those yet.

Here is another picture of the flowers. An interesting thing was that the species with cut-leaves were blooming while the ones with triangular/oval shape were not.

Ambrosia chamissonis in bloom

And here is a picture of the stem:

Ambrosia chamissonis close-up of the stem

Want to see a hairy stem? Here it is:

Ambrosia chamissonis hairy stem

And one more:

Ambrosia chamissonis stem and leaves

Yes, I know I ran amok with this one.  But it is exciting to find some new plant and to be able to identify it quickly.

Like other plants with clusters of usually tiny or very small flowers ragweeds are wind pollinated. These kind of plants may cause hay fever because they need wind to have their pollen spread out unlike flowers that are pollinated by insects. Incidentally this Ambrosia happens to have male and female flowers growing on the same plant.

Why is this plant called Ambrosia (it's a Latin name, too)? Good question. It has smell, not unpleasant but nothing to invoke images of the famous food of the gods. I don't think it is even used as spice.The common name ragweed speaks for itself.