How To Identify Plants At The Santa Rosa Plateau

"Give a man a fish; you have fed him for today. Teach a man to fish; and you have fed him for a lifetime"-Author unknown
Today, I will give you the information and tools you need to identify plants at the Santa Rosa Plateau.
You probably will not learn any species, because that requires homework on your part.
But you will leave this class today with the ability to identify, on your own, 16 of the most common trees and shrubs on the Granite Loop Trail.
My talk is for people who know nothing about plants. If you don't understand something, stop me and ask.
Pictures
Why Identify (ID) plants?
Plant Names
Some Plant Facts To Help You ID Plants
How To ID Plants At The Santa Rosa Plateau
Handouts
(unidentified flowers)
(identified flowers)
Which page did you like best? (;-)
(Scientific) Names tell you uniquely which species a given plant is.
Names are a key to communication about that species with other people.
Naming things is what people do. A name gives us a connection to each species.
If you are a docent, people will ask you!
Names are a way to learn more about a given species.
Common names are often beautiful and descriptive. Red maids, goldfields, milk maids, chocolate lily, etc.
Common names are not unique. There are TWO rattlesnake weeds at the srp: Daucus pusillus and Chamaesyce albomarginata. There are SIX vinegar weeds just in Southern California.
The European White Waterlily (Nymphaea alba) has 15 different common English names, 44 French, 105 German, and 81 Dutch names, a total of over 245 common names!
The same species can have many common names. Creek senecio, Bush senecio, Douglas' groundsel, Douglas' ragwort, Douglas' shrubby ragwort, Shrubby Butterweed, bush groundsel all refer to Senecio flaccidus var. douglasii.
Worse, many plants do not have common names and many species share the identical common name.
Common names often only work locally. Umbellularia californica is known as California bay in California, but Oregon myrtle in Oregon. You'd never know this was the same plant!
Because plants are important medicinally, it is very important to make sure you have the right plant!
Due to the problems of common names, prior to 1735 treatises described each plant, in Latin, without a name, in enough detail to make sure you got the right one.
Carolus (Carl) Linnaeus had a good idea in 1735: he published a flora, with the usual description of each plant, and then gave each plant a binomial name, in Latin.
The first part of the name, the genus, lumped together similar species, and corresponds to your last name. The second part, the specific epithet, identifies uniquely the species within the genus. Both parts are italicized (common names are not).
This is not a difficult concept! Examples: Homo sapiens, Tyrannosaurus rex, etc.
These binomial names solved the problem of knowing precisely which plant is being referred to. "You could look it up".
Bottom line: the only way to make sure which plant you are dealing with is to know its Latin name.
Latin names are not hard! They are just often unfamiliar to you.
Do you have any trouble with: Philodendron, Zinnia, Hosta, Liquidambar, Chrysanthemum, Camellia, Tyrannosaurus rex, Homo sapiens, Rhododendron, Impatiens, Dianthus?
Any gardener knows that the flowers in the Sunset Western Garden Book are organized by Latin names.
If you are learning the common name for a plant, you should spend a few more seconds to learn the Latin name.
Biggest problem with Latin names: the darn things keep changing.
Botanists tried to do two things with the name: identify a species and indicate the relationship of the species.
Thus every time we learn something new about species relationships, or a lumper or a splitter reorganizes a group of plants, new Latin names are given.
Thus about 1/3 of all the species in Southern California have had their name changed between 1974 and 1993. Some plant species have had 10 or 20 different names. But the Latin names still uniquely identify a species because they are never re-used.
Some Latin names are hard to say. But the nice thing is: there is no standard pronunciation. Pronounce them however you like!
How Species Are Defined And Separated
We Are Defining Species In A Snapshot of Current Plant Evolution
Plant Distribution: Rare plants are common; common plants are rare
Botanists define a species based on how it is different from other species
To propose a new species, a botanist has to publish exactly how to distinguish the new species from all other species.
In the paper, the botanist usually also gives a key which tells how to do this.
The key never is presented as "look at this pix; it looks different from all other species".
No one is forced to accept the new species; each botanist decides for themselves whether to accept it.
An indented-couplet key to distinguish the four most common species of oaks at the SRP:
1. plant [is] a tree
     2. leaves flat, bluish-gray or grayish-green .... Engelmann oak, Quercus engelmannii
     2' leaves with edges curled downward, green ..... coast live oak, Quercus agrifolia var. agrifolia
1' plant [is] a shrub
     3. leaf margin mostly with no teeth or very minor teeth, leaves often longer than 30 mm (1.2") .... hybrid scrub oak, Quercus berberidifolia X Q. engelmannii
     3'. leaf margin mostly with evident teeth, leaves mostly less than 30 mm (1.2") long .... scrub oak, Quercus berberidifolia
A non-indented couplet key to distinguish the four most common species of oaks at the SRP:
1. plant a tree (go to 2)
1' plant a shrub (go to 3)
2. leaves flat, bluish-gray or grayish-green .... Engelmann oak, Quercus engelmannii
2' leaves with edges curled downward, green ..... coast live oak, Quercus agrifolia var. agrifolia
3. leaf margin mostly with no teeth or very minor teeth, leaves often longer than 30 mm (1.2") .... hybrid scrub oak, Quercus berberidifolia X Q. engelmannii
3'. leaf margin mostly with evident teeth, leaves mostly less than 30 mm (1.2") long .... scrub oak, Quercus berberidifolia
This key assumes you know you have an oak, perhaps by observing acorns on the plant.
Just like in every other human endeavor, you have to learn the lingo.
A tree in general has a single trunk, and is usually quite tall.
A shrub has multiple trunks, and is usually shorter than a tree.
Teeth are usually sharp projections on the edge of a leaf
There is no concept in plant identification than a 12 year old can't understand.
In botany there are few absolutes.
The definition of shrub height is only loosely stated relative to that of a tree; no number is given.
Note the mostly and often and usually in the key. I call these weasel words! You will find many specimens that violate them.
All too often, the only way to understand a key, and be sure you have it right, is to see all the species in the key.
We'll do this today for a key to 24 shrubs and trees on the Granite Loop Trail.
Note that keying can be fun! You start with a mystery plant, and your job is to use a key to figure out its name.
Imagine beginning with a single plant species at one moment in time. At first, there is just a range of variation in a single species.
In time, that single plant species begins to differentiate, usually at the edges of its spatial distribution.
Eventually, they become two almost-separate species that are hard to differentiate.
Finally, they become two clearly-separate species.
At any given moment in time, some plant species are in each of these stages!
Therefore, some plant species will be easy to separate; others will be difficult and confusing.
There will be arguments about whether some plant species should be separated or combined.
The best keys take advantage of whatever characteristics vary the most between species AND reliably go with each species. However, even the best key will still be confusing for confusing species.
Some of the worst keys are written by botanists who again try to do two things at once: provide a key AND indicate evolutionary relationships. These keys sometimes rely on very obscure, difficult features. If you have one of those, find a different key!
Note: species are not defined by whether they can reproduce with another species or not. Plants are promiscuous; species often can and do reproduce with each other, and the hybrids can reproduce themselves indefinitely.
A fundamental law of biology: the number of species is proportional to roughly the third root of area. This is true for animals and plants.
It makes sense! More area allows more species to exist. The number of species cannot increase as fast as the area, since some species will be found in the larger area.
Thus the rule of thumb: if you consider an area ten times larger, you will find twice as many species.
A direct consequence of this law of biology is that most species are not widespread; they are found only locally. After all, if the number of species grows with area, as you enlarge your area you have to keep encountering species you haven't seen anyplace else before.
(If you have trouble with numbers, just accept this and skip to viewgraph 24.)
Define one area as the north half of the SRPER, and another area as the south half. The number of species in the combined area is the third root of 2, about 1.25, times the number in each half. 0.25 out of 1.25, or 20%, of the total species will thus be found only in each half, making a total of 40% of the species will be found only in one half or the other. Only 60% of the species will be found in both areas.
The same calculation applies considering one area to be the Vernal Pool Trail and another area to be the Los Santos Trail.
After you continue to double the area enough times, there will be very few species that are found in each area A. Most species will be found in only a few of the areas of size A!
Thus common plants (ones found in each of the areas A) are rare; rare plants (ones found in only a few areas of size A) are common.
Note that there may be thousands of individuals of a rare species where it grows. It is only that it is found in only a single area A that makes it a rare species.
Example: our two most common tarweeds, San Diego tarweed (Hemizonia paniculata) and sticky tarweed (Holocarpha virgata ssp. elongata), are only found on the SRP trails out of the 68 trails I've covered in Southern California.
Actual data from 1,980 taxa (species and subspecies) found on 53 plant lists:
(Note to those whose eyes are now glazed over: time to wake up!)
What does this mean? It means that species are local. Most species at the SRP or anywhere else are found on only one or two trails. We are fooled into thinking that plant species are widespread because we only notice the very few plant species that are indeed widespread.
So you cannot identify most species at the SRP by using a plant list or flower book from somewhere else, such as the Santa Monica Mountains. Only a small number of species will be found to be in common between two different places. Of course, those will be among the commonest species in each place, so using a picture book from elsewhere may help to identify the most common species. The closer the other area, the more matches there will be.
Example: the SRP wildflower photo book of the most common wildflowers has 5-10% of the species incorrectly identified because they used a Santa Monica Mountains (SMM) plant book to identify our flowers. The error rate would be much higher for less common wildflowers.
Example: there are five species of "purple nightshade" in California, whose flowers all look very similar. In the SMM area, the species is Solanum xanti. At the SRP and in San Diego County, the species is Solanum parishii, Parish's purple nightshade.
The single most important step by far: Get a copy of the SRP Plant List!!! Every plant you will see is on that list; if it isn't, I want to know about it.
There are 636 taxa recorded in the entire SRP region; ~380 are at the SRPER. Of those, there are ~195 noticeable flowers, shrubs and trees found on the trails, with ~109 being common. Gordon House has ~125 taxa on all of his plants in bloom lists combined.
Three different approaches:
- Walk the trails with someone who knows the plants.
- Use plant pictures.
- Learn how to key out plants.
Walk the trails with me, Zach Principe, Gordon House, Kay Madore and ask us what the names are. More important, ask us how to identify that plant to tell it apart from look-alikes.
Never try to learn more than 3 plants per day. If you try to do so, you'll start confusing them, and won't have learned them.
For the 1-3 species you are learning each day, touch the plants (the only exception at the SRP is poison oak); smell the plants, the flowers and the leaves; look at the flowers up close, the leaves, the flower bracts, the stems, etc. Do this 20 times as you go along the trail for each species, and say the name out loud to yourself each time. Note how each plant and flower is slightly different.
Make notes about this plant you can consult in the future. Everyone has their own favorite characters to recognize each species.
When you get home, look up the plant in any books you have, or online. You'll probably learn something very interesting about the plant, or something you didn't observe in the field. Look at the pictures of the plant to see how the species varies.
Try to come back within a week or two and do the exact same things on the same trail, but this time noting the things about the plant you learned at home. Say hello to the plant when you see it at first, and call it by name!
Walk the same trail repeatedly and note changes in the plant, from the flower to fruit, to the fruit ending, to the plant before bloom in the next year. Note how the blooms sometimes change from the first bloom of the season to the last bloom. Note the weird things that occasionally happen, such as galls or fasciation.
Kay Madore learned over 100 species last year by doing much of the above. In the process, she discovered 3 species not on the plant list, and was credited for being the one to add 2 of them to the plant list (she was scooped on one by Zach; she scooped me on one).
Walking a single trail repeatedly through a season or year is the best way to learn most of the showy flowers and major plants. Remember: even neighboring trails differ greatly. The only way to own a trail, and know the plants on a trail, is to walk that trail repeatedly.
Use my plant lists for each trail! They narrow down the species even further than the entire SRP plant list.
If you are on your own, without an expert nearby, you'll have to do more work. If you haven't yet learned to key out plants, you'll need to use pictures.
Using pictures can be extremely frustrating; here are tips to do it more efficiently.
First, note where on which trail your plant is blooming. Note whether the plant is a shrub or not. Note whether the flower is symmetric or not, the number of petals, their color, whether the leaves are opposite or alternate, and what the leaves look like. Write these things down, and take a pix if you can.
Many times, someone else at the SRP can later tell you just from that information what the plant is. Ask someone at the Visitor Center if it is open. Look through the SRP picture book; maybe you'll get lucky and find it there. (I'll fix the picture book in the next month!)
If you get no match that way, you can email me with that info and any pix. Usually the location is the most important thing for me to give you the id!
If someone gives you a name, check the plant list to see if that plant is on the list. If so, confirm the id with a picture.
If you can't find anyone to ask, then look at my list of plants blooming now at the SRP, and the list of all plants on your trail, if one exists. Then look at plant pictures just for those plants blooming now that are on that trail.
If you don't find a match, maybe the plant has just begun blooming and hasn't made it to my bloom list yet. Also, the SRP is a big place; maybe I haven't seen it yet. In this case, go to the list of the most common species, and look for all plants that can bloom in the month you saw the blooms. Again, then only consider ones on that trail.
This is the real secret of plant identification: using a plant list. You can then narrow your plant down from 4,000 species in Southern California to fewer than 100, and perhaps just 10 or so, on that trail blooming at that time.
If you can key the plant to a family, the id will be much, much easier. Use the family key in the Peterson Field Guide to Pacific States Wildflowers, which is made for beginners. This can often narrow the choices down to 10 or fewer easily.
Picture matches will fail for a handful of species! Examples:
Brodiaeas. You have to look carefully inside the flower to tell our three species apart.
Owl's clover. We have two nearly identical species that are separated by looking at whether a small part of the flower is fuzzy or not. This will not show up in most pictures. Fortunately, our species separate by location.
Tarweeds. We have three very similar species, which are distinguished by counting the number of petals. San Diego tarweed, Hemizonia paniculata always has 8 petals; slender tarweed, Hemizonia fasciculata always has 6 petals; and sticky tarweed, Holocarpha virgata ssp. elongata has 3-6 petals.
Learning to key out plants is the most fun way. Once you learn how to key out plants, you are empowered! You can figure out the id of any plant yourself. You don't have to ask anyone, or spend frustrating hours looking through pictures.
Instead, you can then spend frustrating hours trying to use the key. (;-)
The best way to learn how to key out plants is to take a class from a local college. Nearly all of them offer classes like Botany 110: Botany of Spring Wildflowers (Palomar Community College), or Plant Identification.