Urban Habitat

ah, ah, ah, ah, stamen alive. stamen alive.

Stamen: the “male” reproductive organ of a plant

I’m taking an introductory botany class from my local botanical garden, starting this week! This is the first course in a series to gain me my Sustainable Gardener’s Certification, which I should have by some time in 2024. This post is the first in a four-part series sharing what I’ve learned in Botany 101.

Who Cares about Botany?

Well, I do, obviously. But why? As humans we want to put things neatly into boxes – pattern recognition is sort of our thing. And as a certified-biologist human, to some extent I want to do that too. However my larger interest in botany is what it can teach us about the relationships between plants. Studying botany asks more questions than it answers, and that’s what I enjoy most about it. Botany pushes us into a more fascinating relationship with our natural world.

For example – a large part of botany is identifying plants based on leaf shapes and patterns. One leaf pattern is called “whorled,” where leaves wrap all the way around the plant’s stem. This is a very rare leaf pattern and so it stands out in plant identification. But – why is it so rare? Categorizing plants doesn’t tell us this; it just begs the question.

The Basics: Taxonomy

Plant Taxonomy

All plants are in the domain Eukarya and the kingdom Plantae.

From there, we break down into a number of phyla, which contain a number of classes, which contain a number of orders, etcetera etcetera down to hundreds of millions of plant species. But let’s focus on two specific phyla: angiosperms (angiospermophyta) and gymnosperms (gymnospermophyta). Angiospermophyta are your flowering plants; gymnospermophyta are your “naked seed” plants, such as conifers.

Note that as we move down the taxonomic chart from domain to species, the organisms named the same get more and more similar to one another. So two plants that are angiosperms are more similar to one another than is an angiosperm to a gymnosperm. This “similarness” is complicated by modern-day genetic methods, which is why you might have heard that taxonomic categories change! You can imagine that a hundred years ago botanists looked at plants with the naked eye and grouped what looked or behaved alike; now we still have our five senses, but we also have the ability to sequence the genomes of plants and discover how close their genes are to one another.

Then, within the angiosperms we have two classes: dicots (dicotyledons) and monocots (monocotyledons).

Dicots & Monocots

There are only two types of angiosperms in our current understanding: dicots and monocots. Dicots – dicotelydons – have two baby leaves: di (two) cotyledon (baby leaf from a germinated seed). You can imagine then that a monocot – monocotyledon – has just one embryonic leaf, or cotyledon.

This difference apparently confers other physical differences, one of which can be a simple way to visually identify dicots vs. monocots: The veins of dicot leaves form a netlike pattern, while the veins of monocot leaves are parallel. Isn’t it curious why they should have such a difference?

The Major Dicot Families

Now, in the dicot class there are plenty of families, but there are six families that I can almost guarantee you know a plant from, because they’re common in gardens and meals. These are:

(1) Fabaceae. This is your fabulous pea plants, your honey locusts, and your black locusts.

(2) Brassicaceae. This is your ‘cruciferous’ vegetables, like broccoli and cabbage, plus mustards.

(3) Apiaceae: This is your carrots, dill, parsley, and the like.

(4) Lamiaceae: This is your aromatics: mint, lavendar, etcetera.

(5) Asteraceae: This is, you guessed it, asters – those beautiful simple star-like flowers.

(6) Roseaceae: This is, most obviously, your roses, but also includes fruiting trees like pears and apples.

Family Planting

A lot of taxonomy can feel like pointless patterning of living things: this is like this, that’s like that, blah blah. Of course this is very useful for science and research, but what about for your Average Joanna? Well, if your Average Joanna gardens, knowing what plants are related to what other plants – and/or what plants make what other plants sick, or make other plants grow better – is a massive green-thumb up.

For example: plants in the same family, say the mint family Lamiaceae, will likely require similar conditions to thrive. I know this first hand from my spearmint and basil plants – they both really love moisture, bright sunlight, and do well with trimming. Understanding the similarities and differences between plants and being able to identify which plant is which are great skills for the gardener, the homesteader, or even just the office worker with some houseplants on their desk.