Leaf_type=palm - is anything wrong with it?

[Mateusz_Konieczny]

@milet

The leaf_type of a palm tree should be broadleaved.
The Wikipage of leaf_type actually shows a palm tree as one of the example pictures for the value broadleaved.

To mark a tree as palm tree, other tags should be used.

Ouch, I somehow missed it. I created Tag:leaf_type=palm - OpenStreetMap Wiki to reduce such risk in future.

[Kai_Johnson]

We recently had a discussion about this exact topic in OSMUS Slack, focused on how to tag the variety of plants in the Southwest US that don’t fit well with the established OSM tags and can’t be easily categorized using leaf_type=*.

In the end, there was some agreement that taxon:family=* does what we would want in this case.

Here are some examples:

taxon:family=Arecaceae - A palm tree or plant. I think there was some confusion above that there could be some things that are palms that are not in this family. That’s really not true.

File:One Palm Tree.jpg

taxon:family=Cactacae - A cactus “tree” or plant. Although the Saguaro is probably the most iconic example, we have to keep in mind that it grows only in Arizona and Sonora.

File:Carnegiea gigantea or Sahuaro or Saguaro.jpg

taxon:family=Asparagaceae - As a tree, this is a Joshua Tree. It would be a mistake to call this leaf_type=palm because that’s not what it is. It’s actually a type of yucca.

File:Joshua-tree Yucca brevifolia in-bud tree.jpg

As a plant, Asparagaceae is a yucca or agave.

File:Agave americana R01.jpg

If we try to characterize these plants by their attributes, we find that the yuccas are both broadleaved and spiny. In fact, many palms have nasty sharp thorns as well. So, attempting to identify these plans by leaf_type=* fails to make the distinctions between cactus, palm, and yucca.

[mariotomo]

@Kovoschiz

taxon:*= is more scalable

that is the reason why I started using taxon:family for Arecaceae a while ago, when I first met the issue. I also keep using e.g. genus and do not advocate taxon:genus just because they are established tags, while family wasn’t at the time when I needed it.
Should there come a vote for deprecating unprefixed genus and species, and state that they be prefixed with taxon:, I would vote in favour.

[mariotomo]

@Kai_Johnson

I think there was some confusion above that there could be some things that are palms that are not in this family. That’s really not true.

Palms, if taken as all that fall under the family Palmae, are simply an other name for Arecaceae. OTOH, there’s plants that sort of look like palms, or even hold “palm” in their vernacular names.

consider the “traveller’s palm”, which despite its name isn’t a palm at all, but is related to bananas, heliconias and ginger.

also most Cycadaceae might look to uninitiated like palm trees.

maybe some might even confuse some ferns with a palm tree.