Pome fruits and plant families

So as promised, the next few entries are going to walk through the major categories of fruits. Now I'm not doing this just because I might run out of winter-interest plants to talk about at the rate I'm going, but mainly because I think that aside from people who tend a garden or care for houseplants; culinary fruits, nuts, and seeds might be the part of the plant most familiar.

Though terms like drupe can be a bit esoteric, you're already aware of what makes a peach different from an orange. Even though you might not think to describe the orange as a berry or the peach as a drupe, being able to notice these differences and knowing what to look for, in my mind, is more important than the specific vocabulary. I think this will be an easy way to show that you know more than you think you do, as well as a good way to start gaining an appreciation for the way a botanist hones in on certain characteristics to determine what makes certain plants more similar to each other.

So we already know that a drupe is a fruit with one single pitted seed (peaches) and a berry is one with multiple seeds (blueberry, banana, etc), now for the third type of wet fruit; the pome.

Not really sure why I bought this... not a big golden delicious fan

Pomes have multiple seeds, but unlike the berry, the seeds aren't just hanging out wherever. They're kept in a "case" at the center of the fruit. You guessed it, the "core" we know from apples. Though the core (endocarp) isn't quite as stony as you'd find in the pit of a drupe, it is noticeable more solid than the fruit (mesocarp) surrounding it

Nicely labeled diagram from Wikipedia's entry on the Pome

So now we know our wet fruits. Take a fruit and cut it open. If there's a single seed in a pit, it's a drupe. If there are multiple seeds confined in a core, it's a pome, and there are multiple seeds scatted throughout, it's a berry.

Easy, right? Leaves us plenty of time to go into something else I find interesting about the pome: the fact that despite how familiar they are to us (apples are usually the first fruit that comes to my mind anyway), they're actually somewhat uncommon in nature, or at least far less so than the drupe or berry.  Only plants in the Rose Family produce them, and even then, not all of the genera in that family do.

Family? Genera? I think it's time for a brief review of the phylogenetic tree (or the "tree of life")

Now as you may remember from high school bio, the major divisions we use to categorize a living thing are (from most to least broad)... Kingdom, Phylum, Class, Order, Family, Genus, and Species (my bio teacher passed down the acronym "Kings play checkers on fuzzy green squares" as a mnemonic device)

I've already been using genera and species in this blog, any time I list a scientific name. For example, the Red Oak, or Quercus rubra: rubra, the species, means "red", and Quercus the genus, is the term for "oak".

As for the other levels, the only one we need to worry about right now is the family, that next level up which starts to group some of these different genera together (sticking with our Red Oaks example; Oaks, Beeches, and Chestnuts all make up the Beech Family). As for kingdom, all I'm probably going to talk about here are plants (unless I start taking photos of mushrooms or something), so we can pretty much forget about that. and we'll save the rest of the levels for later when I talk about a pine tree or something.

So apples are actually in the Rose Family, meaning the trees producing the apples we like to eat are pretty closely related to the shrubs and vines producing the roses we like to look at. This comes as a surprise to some, since as a society, we generally place a big distinction between ornamental plants and culinary plants. However, the way the plant is used is not how it is botanically categorized: most of classical taxonomy is done by floral characteristics, so the fact that both the apple tree and the shrub rose have a flower with typically five petals and stamens is more important than whether it produces a fruit we find appetizing.

I don't have any close-up photos of apple blossoms though (closest thing I found on my HD was a long shot of a flowering pear), so you'll have to take my word for it.

So we now know all of our "wet" fruit types, as well as some of the groupings that Taxonomists use to lump plants together. Next time we'll start going into the dry fruits. There are a few more, but once again I think you'll find many of them are already familiar to you.

Further Reading

Well in this case, it's viewing as. the Khan Academy has a great video about Taxonomy and the Tree of Life in case you're looking for a little more depth on that.

Also, did you ever wonder what the numbered code of the sticker on an apple (or any produce for that matter) stood for? I never paid much attention to it myself until I started using self-checkouts at the supermarket, but there is actually a difference in how the fruit has been raised depending on whether you see a four or five digit code.

A four digit code tells you the plant was grown using normal methods (so pesticides and all that), whereas a five digit code can mean one of two things. If the code starts with a 9, it was raised organically (no pesticides). If the code starts with an 8, the plant was genetically modified.

I don't think I've ever seen an 8 (or a 9 for that matter since I rarely buy organic produce), but I'll keep an eye out for either next time I'm at the Pathmark.