Posts Tagged ‘virtual plant walk’

Guest Post: Our Exotic Urban Forest

This is a guest post by Nancy Nordman from Our City Forest, San Jose’s urban forestry group. Our City Forest is a non-profit organization that provides free trees and tree advice to San Jose residents and promotes greenery in our urban environment. They’ve planted some 65,000 trees in San Jose! Here, Nancy takes us on a tree walk of the urban forest around San Jose’s Rosicrucian Egyptian Museum. Why not poke around and see what’s growing in yours?

When I first started as an AmeriCorps member at Our City Forest, I probably couldn’t name even ten different tree species, let alone classify the species I was standing under.  I knew plenty about how trees used photosynthesis to make food and I definitely had an appreciation for the benefits trees provide to us and the environment.   But ask me to tell the difference between an Ash and an Elm?  At that point, your guess was as good as mine.

Once I found out I would be leading tree tours around the city, I began to poke around looking for any information that could help me – field guides, the internet, and my enthusiastic co-workers.   I found there to be incredible diversity just among the 65,000 trees planted by Our City Forest. I  began to see opportunities everywhere I looked for more greenery to be added to this city to make it healthier, more efficient, and more beautiful.

At Our City Forest, we are often asked why we allow any planting of non-native trees.  While we are a strong advocate of planting native trees, there are numerous situations where planting non-natives actually makes more sense.  As the city of San Jose has grown, urbanization has drastically altered the native environment, so some natives can no longer thrive in the urban setting.  Oftentimes we plant drought tolerant non-native trees from similar Mediterranean climates that can handle harsh urban challenges such as smog.  Species diversity is also incredibly important to maintaining the health of an urban forest so that if a disease comes through, the tree population can make a comeback.

The wonderful thing about all this diversity is that you don’t need to go somewhere special to see a bunch of different trees!  I encourage you to take a walk along your street and just try to notice the urban forest around you.  To get you started, here are some great trees to check out at the Rosicrucian Egyptian Museum in San Jose.  (There are around 50 different tree species within the grounds of the Rosicrucian Museum alone!)

Canary Island Palm. Photo credit: Our City Forest

Canary Island Palm (Phoenix canariensis)

Where better to start than a “tree” that is not really a tree?  Palms are technically classified as grasses.  Unlike true trees, palms do not undergo secondary growth and therefore do not produce true wood, but rather a fibrous trunk structure.  There are also differences in their growth and structure as well as their root system.

In contrast to the equally common Mexican Fan Palm, Canary Island Palms are shorter and stockier and have pinnate feathery leaves instead of the fan palmate structure of the Mexican Fan Palm.  If you still aren’t sure which palm it is, look underneath the feathery stalks hanging down and you can usually see what looks like a large pineapple.   The Canary Island Palm does in fact come from the Canary Islands and is highly ornamental, sporting large, orange, edible dates.

Jacarandas in bloom. Photo credit: Frank Reyes

Jacaranda (Jacaranda mimosifolia)

If you are looking to see some color in our urban forest, keep your eyes peeled for the gorgeous Jacaranda trees!  Though found all over San Jose, these trees originate from the tropical environment of Brazil and Argentina and have since been introduced all over the world.  Their popularity is thanks to the large showy violet flowers that appear in late spring or early summer.  Also interesting to note is the large brown clamshell seedpods and the fern-like compound leaves.  These trees are located throughout the museum grounds, but are mainly located near the obelisk.

Irish Yew. Photo credit: Our City Forest

Irish Yew (Taxus baccata)

On the side of the museum directly across from the Starbucks, you will see two short stocky bush-like trees.  But don’t be fooled, they may look tiny but these trees are some of the most formidable trees on the whole grounds!  Bearing toxic wood and leaves, these trees are also extremely long-lived, up to 4000 years!  It is said that bow makers and other wood craftsmen would get sick from working with this wood.  Originating in Europe, this tree was often planted in cemeteries as a symbol of transcendence after death.  They can be identified by their flat dark green leaves and red seeds, which are very much enjoyed by bird species that don’t find them toxic.

White mulberry. Photo credit: Our City Forest

White Mulberry (Morus alba)

If you cared for silkworms in elementary school, you may know that they will only eat mulberry leaves.  The White Mulberry is appreciated here in San Jose for its fast growth and ability to handle pruning.  Less known but certainly more impressive is its ability to shoot out pollen at 350 miles per hour — one of the fastest movements in the plant kingdom!  There is a particularly great White Mulberry on the museum grounds next to the Akhenaten Shrine and near the Peace Garden.

Olive tree. Photo Credit: Our City Forest

Olive (Olea europea)

Possibly my favorite tree yet is the Olive tree, mainly for its incredibly beautiful silver-gray leaves and whorled trunk.  You likely know this tree for its production of olives, or perhaps from its history of use for crowns in ancient Olympic games. The Olive tree does very well in San Jose’s climate because it originally comes from the Mediterranean Basin, making it quite drought tolerant.  Worldwide, the olive tree stands for peace and wisdom and the museum has dedicated a large section of the grounds to these magnificent trees.

Dawn Redwood. Photo credit: Our City Forest.

Dawn Redwood (Metasequoia glyptostroboides)

Tucked in a corner by the library and rose garden of the museum, you will find a gem of a specimen—a huge Dawn Redwood!  These fantastic trees were actually widely thought to be extinct, but as they were attempting to classify fossil records of the leaves, a matching specimen was found in an area of central China.  Similar to the ginkgo, this tree is considered a “living fossil.”  Don’t be surprised if you find this tree looking dead in the autumn and winter.  The Dawn Redwood is the only living deciduous redwood species and so it will turn a beautiful bronze color and then drop its feathery leaves, taking on a skeletal appearance.

Bunya Pine (Araucaria bidwilli)

To the left of the main entrance to the museum are a couple of Bunya Pines, which are an interesting evergreen species from Southeastern Queensland.  Take a close look at the branches which have tufts of leaves at the ends and few by the trunk — but do watch for large falling seed cones!  The edible cones get as heavy as 10-15lbs, so during fruiting season this tree can be quite dangerous!  From far off, it is very pretty with its branches forming a rounded dome structure toward the top.


I hope you enjoyed this brief tour of the unique non-native trees you can discover in San Jose!  As I continue to learn more about trees, I find my appreciation of their beauty and function is constantly growing.  Trees are already working hard filtering pollutants out of the air, cleaning our water, and providing home for critical wildlife species.  I hope you will join Our City Forest in advocating for a vast and healthy urban forest!  If you wish to learn more about trees and urban forestry, check out the Our City Forest website, like us on Facebook, come out and volunteer with us, or consider getting a tree from our nursery!  We also have free educational tree tours and classroom presentations.  Our City Forest is a nonprofit that has been providing free trees for residents, schools, and parks across San Jose since 1994.  For more information on our planting, tree care, and educational programs, visit our website or call (408) 998-7337.

Jennifer: Do you know what’s growing in your urban forest? On my street are maples, ashes, sweetgums, olives, birches, redwoods, redbuds, gingkos, and Chinese pistachios, just to name a few. Going on a tree walk with a knowledgeable local is a great way to learn about the forest you live in. Thanks, Nancy!

In praise of weeds

Dandelion. Photo credit: David Hepworth

If you can eat, breathe, or exist, thank a plant. Plants often get the short end of the stick when it comes to Things Humans Are Interested In. They’re not all that cute (some might surprise you), they don’t talk (at least not to us), and all in all, compared to your average smart phone or polar bear, seem pretty boring. Yet all the organic carbon on this planet ultimately comes from plants.

From your windowsill miniature rose to the predatory bird of paradise in your backyard, all plants are busy wrenching apart water and carbon dioxide molecules, stripping them of hydrogen and carbon atoms to make organic hydrocarbons (plant sugars). Humans can’t do this. Your Android can’t do this. My fuzzy gray cat can’t do this. Only plants (and algae) do this. Almost every food chain everywhere on the planet starts with plants. 

I’ve taken you on a number of virtual nature walks (woodstreespoisonous plants), but now I’d like to introduce you to the most common and least loved plants of all: weeds.  Weeds are one of the ways I first started to interact with the natural (naturalish?) world. I’ll be fond of them until / unless I start trying to grow things on purpose.

I grew up in my mom’s postage stamp sized garden in northern California. She wasn’t a fastidious gardener (still isn’t), and I was short (and still am), so I paid as much attention to crawling weeds as I did the taller stuff. At that age, I didn’t recognize a distinction between wanted and unwanted plants. Sorry, Mom. I’m responsible for your dandelion explosions. <Poof…>

The names and details came later. Many of them surprised me, since the books that I had first read about these plants led me to expect something…bigger. Grander. Less common. But the more I learned, the more interested I was for their own sake. Here’s a virtual garden of weeds I grew up with. What weeds are in your yard?

Sorrel (genus: oxalis)

Woodsorrel. Photo credit: Pellaea

I thought these were shamrocks for the longest time. One of their alternate names is actually False Shamrock. I wonder if you’re still lucky if you find a four-leafed oxalis? The most common type of sorrel I know has tiny yellow flowers, but among the shade of the redwoods, sorrel has big heart-shaped leaves and tall pink flowers. Oxalic acid gives sorrel a tart flavor. In large doses, oxalic acid causes kidney stones, so if you’re trying to keep yourself alive after the zombie apocalypse, don’t eat too much sorrel. Nice accent on a salad, though. (Note: don’t forage near roads or where plants have been heavily sprayed, like most lawns.)

Clover (genus: Trifolium)

Clover. Photo credit: Public Domain Photos

Clover flowers make nice daisy chains. I cleverly figured this out for myself while sitting in outfield during the softball unit of PE each year. (This should tell you something about my athletic prowess.) It also flavors honey and feeds cows. Red clover increases cows’ milk output, but too much clover can lead to fatal cow bloat. Burr clover has pointy spurred burrs that stick to clothing and fur, so watch out.

Scarlet Pimpernel (genus: Anagallis)

Scarlet Pimpernel. Photo credit: Rictor Norton and David Allen

Instead of crushing on boy band members as a teen, I crushed on well-dressed fictional gentlemen in cravats, including the Scarlet Pimpernel. After reading the book, I hopped online to see what a scarlet pimpernel looked like and was devastated to find that it was neither scarlet (salmon…maybe) nor impressive (flowers are usually smaller than 1/2″). In fact, this was the same unheroic weed that had taken over one corner of my mom’s yard years earlier. My mom was similarly unbelieving when I pointed it out to her on a walk many years later. Despite my disappointment, I still think scarlet pimpernels are pretty. But should anyone be looking for an emblem under which to subvert the French government, may I suggest the star glory instead?

Rattlesnake Weed (genus: Euphorbia)

Rattlesnake Weed. Photo credit: David~O

This one grew in the mortar between bricks, which says something about its tenacity. The stems are filled with a sticky, milky sap that is intensely bitter. Bitterness is often an indication that something has toxic alkaloids. Good thing I never took more than a lick! A tea made from rattlesnake weed was an herbal remedy for snake bites, but you probably don’t want to take a chance on it. Euphorbs are characterized by toxic milky saps that can blister, so although nothing ever happened to me from playing with rattlesnake weed, handle with care. As a rule of thumb, don’t eat a wild plant that has milky sap. And if you taste any plant that is bitter or makes your mouth tingle, put it down at once!

Purslane (genus: Portulaca)

Purslane. Photo credit: Frankenstoen

I recently found out purslane was edible, so this summer, when my mother was ready to weed her garden, I asked her to save the purslane for me. I tried it with scrambled eggs and mushrooms. It wasn’t bad, though a little slimy. The technical term, I believe, is ‘mucilaginous.’ Most importantly: I didn’t die! Purslane is a succulent with a slightly tart edge and interesting texture. If you’re going to eat it, don’t harvest from areas subject to spraying (either from pesticides or dogs).

Pineapple Weed (genus: Matricaria)

Pineapple Weed. Photo credit: ArranET

This small plant with rounded yellow flowers and lacy leaves didn’t grow in my mom’s backyard, but it did grow at my school. When I learned the name, I figured that the flowers look maybe a little (if you turn your head to the side and squint?) like upside down pineapples. But actually, if you pinch a flower open, they have a pleasant, fruity smell that has a hint of pineapple to it. Pineapple weed is related to chamomile, although more bitter, and if you’re in a pinch, rubbing the plant on your skin is supposed to repel insects.


Even recognizing that weeds are a tremendous agricultural problem with no good solution (till and you degrade the soil; no-till and you have to use herbicides), I feel a certain admiration for these hardy, unwanted plants that survive despite the harshest conditions — no water, poor soil, herbicides, insects, fierce competition. They’re continually evolving resistance to our most powerful herbicides and other ways to kill them.

We city dwellers often bemoan the lack of nature in our immediate surroundings, but I dunno…maybe it’s just that we don’t pay enough attention. Do you know what weeds grow around you?

Weed identification resources:

Also, this is what I’ve been up to lately.

Meet the Poisonous Plants In Your Backyard

Lily of the Valley (Convallaria majalis). Pretty, delicate, toxic. Image credit: Leo-seta.

Sadly, the internet tells me that there’s no such thing as a toxophile or toxicophile. If there were, I’d make a blog button for it. (Other suggested blog buttons for my site: Anti-Social Media Expert — thanks, Karen — and Evolutionary Dead End. Alas, I don’t know how to make buttons.) Anyway, what I mean to say is that I kind of have a thing about poisons. And by thing, I mean that people who look too closely at the books on my bookshelf might decline an invitation to dinner.

This is what comes of reading too many Agatha Christie books at a young and impressionable age.

Plant poisons are my favorite. I’m always taken aback by how elegantly and creatively nature addresses the problem of being eaten. Plants can’t run, so instead they wage chemical warfare on their predators. The Indian bean tree, for example, produces a nectar with a compound that only affects cheater species that steal nectar — but not pollinators.

And plenty of plants are well-protected not just against insects, but also bigger animals, like humans. There are lots of them, and they’re all around us. I’ve pulled together some of my favorite common wicked plants, a number of which are probably in either your backyard or a backyard near you. Welcome to my virtual poison garden!

(And for crying out loud, teach your kids to respect plants. I sampled my way through my mom’s garden as a kid and got lucky she didn’t have anything really poisonous. Although I guess that could explain some of my peculiarities.)

Nerium oleander. Image credit: heatheronhertravels

Oleanders are, in a sense, perfect garden shrubs. They’re drought resistant, have nice foliage, and produce lovely symmetrical pinwheel flowers that smell nice. They’re also among the deadliest of common garden plants, possessing a number of cardiac glycosides that affect heart function and can cause death. Even honey made from oleander nectar is toxic. (Most deaths by oleander, however, are intentional. By anecdote, a number of seniors have ended their lives by drinking oleander tea because it was readily available in their nursing home garden. That story makes me sad.) Interestingly, oleanders are also being investigated for therapeutic uses in treating cancer. The dose makes the poison.

Viburnum lantana. Image credit: Bosc d’Anjou

Lantanas have peppy colored flowers and nice leaves, but that’s about where the good news ends. They’re invasive in Australia, Hawaii, South Asia, and Southern Africa because 1) birds like the fruit and spread the seeds; and 2) the leaves are toxic to most species. Lantanas, especially the unripe berries, contain pentacylic triterpenoids that cause liver problems and phototoxicity in grazing animals (including small children).

Digitals spp. Image credit: Salt Spring Community

Foxgloves are an old garden favorite. The name has an odd etymology that doesn’t actually involve small reddish quadrupeds (Wiki can tell you all about it). Another name for this plant is deadman’s bells. Foxgloves contain cardiac glycosides and have actually been used to treat some heart conditions since the 18th century. My grandmother, who has had congestive heart failure, is on a synthesized form of digoxin. However, cross the [narrow] therapeutic threshold and foxgloves can cause nausea, halos, delirium, irregular heart rhythms, and death. All parts of the plant are toxic, not just for humans, but also for dogs and cats. Even drinking the water that cut foxgloves are sitting in can be deadly.

Conium maculatum. Image credit: jkirkhart35

I doubt anyone plants poison hemlock on purpose, but it’s a common weed in fields and pastures. It’s quite a delicate looking plant, a spindly 6′ tall with dainty little white flowers. Purple spots or streaking on the stalks are a dead giveaway, but it resembles plants that are edible or medicinal (Queen Anne’s Lace, wild fennel, parsley. Socrates is probably hemlock’s most famous victim. Hemlock contains a highly toxic compound called coniine, which paralyzes the muscles, including the heart. It doesn’t take much to cause death — 100mg of the leaves, root, or seeds.

There are many, many others: nightshades, sago palms, castor bean, angel’s trumpets, water hemlock (as if one deadly hemlock weren’t enough), buttercups, dieffenbachias…just more proof that nature’s chemicals aren’t necessarily safer than manmade ones. Which poisonous plants do you have in your garden? 

OK, I think I’m done poking my naturalistic fallacy in the eye with a sharp stick now. If you’re interested in the topic, you might enjoy:

Virtual Nature Walk: Spring Edition

Last summer I took you on a virtual plant walk of my favorite preserve, the Fremont Older Open Space. Unfortunately, by July, things are pretty dead in California — dead enough to make you suspect that the ‘golden’ part of our ‘golden state’ moniker is a euphemism for dried up and brown.

Totally different story in early April. Oceans of grass up to my knee, budding leaves, and damp soil underfoot that sinks just the right amount when you step on it. It’s impossible for me to be there and not think that I’m an amazingly lucky person to be alive on this planet right now. This feeling is the single most important factor in why I am an environmentalist. We’ve absolutely got something worth protecting in this small blue and green planet.

Want to join me on a virtual nature walk? Just a warning: I am neither a botanist nor a photographer. But if you don’t mind wandering around with an amateur naturalist equipped with a cheap camera, come along! We’re going to sneak in the back entrance of the park this time. The trail starts in a wooded, damp area with lots of early spring vetches (no flowers yet), clovers, and blackberry brambles. Almost immediately, we come across this little guy (actually, slugs are hermaphrodites, and this one, at 7″, isn’t exactly little):

According to Wiki, the Pacific banana slug is the 2nd largest terrestrial slug in the world. Also my college mascot at UC Santa Cruz!

There’s a bizarre tradition of licking banana slugs, which apparently causes numbing due to toxins in the slime, but I’m thinking that I can live without that particular experience. (Also, it’s not good for the slugs.) So we leave it alone and continue up the path. It’s a beautiful morning, all clean air, cloud shadows, and bright light.

As we head up the incline, puffing just a bit, we pass by some coast live oaks with their dark, shiny leaves, plenty of California sagebrush on sunnier slopes, some toyon bushes (also called California holly), distant blue blossoms, and lots of other stuff I don’t know the names of yet. Ask me again in another year. Kevin likes this back entrance to the park because it gets straight to the point — up a steep hill and into the heart of the park. I think I might prefer the gentler entrance myself.

Right, then. At the top of the hill, we swing a right on to the Hayfield Trail, which overlooks lush green hills that are currently covered in wild oat grass. When the wind blows, it sounds like the ocean. The grass is just starting to go to seed; in another few weeks, it will be drying out and dead. In the meantime, it looks lusher than the nearby golf course.

Springtime in the California hills wouldn’t be complete without a couple of these, of course. Our iconic golden poppies are late this year due to the delayed rain, but they’re the usual eyepopping shade of orange. Apparently they’re late risers: it’s almost 10am, and they’ve yet to fully unfurl. I recently learned that golden poppies are not true poppies, but they’re perfectly suited for survival in California, being self-seeding, drought-resistant, OK with poor soil (like on highway shoulders), and easy to cultivate in gardens. There are fewer of them this year because of our weirdly dry and warm winter, but more may come up later.

Continuing down the path, we pass a couple of magnificent old coast live oaks. These rugged trees have deep roots to survive the yearly May-October California drought. The coast live oak also has small, glossy leaves to conserve water — the more surface area of the leaf, the more water the tree loses through evaporation. Live oaks, as the name implies, do not shed their leaves in the winter. California’s live oaks are being threatened by Sudden Oak Death. If you hike in more than one park, be sure to rinse off your shoes so you don’t carry the disease from one area to another.

Feeling a little warm? Let’s stand in the shade of this oak for a few minutes before going on. (Just a note: compressing the soil around trees, i.e. walking on their roots, can damage root systems, especially if lots of people do it. These trees are located just off the trail, but unless I really want to take a better look at something or use a treefinder key, I usually don’t approach.)

We’re passing through several types of mini ecosystems even in a relatively short walk. The fields are turning into dryer, warmer chaparral. On both sides of us are lots of shrubs with attractive glossy leaves that start off reddish when young and then turn bright green. Can you guess what they are?

Remember, unless you’re absolutely sure you know what you’re doing, don’t touch anything with leaves of three. The same compound in poison oak that causes allergic reactions, urushiol, is also found in poison ivy, poison sumac, cashew nut shells, and mango skins (in much smaller quantities). I don’t know if I’m sensitive to urushiol or not, and today is not the day to find out. Poison oak is an important part of this ecosystem, by the way: birds and other animals rely on its berries for food. Just because we thin-skinned humans can’t touch it doesn’t make it a bad plant.

As we round the hill, the air becomes noticeably warmer and stiller. There’s a drop off to the left and something like a cliff face to the right that seems to have created a microclimate. This is my favorite plant along this stretch:

These spiky purple flowers, with their unusual arrangement (several flowers are spaced out along a single stalk like meatballs on a skewer) are a type of local sage, also known as chia. They will produce lots and lots of edible chia seeds after they’re done blooming. If you pinch a leaf, you’ll be able to smell the characteristically pungent odor associated with sages, which are actually in the mint family.

We also see lots of manroot just beginning to form its big spiky seed balls, more feathery sagebrush, and a whole lot of mystery plants. A number of the small elderberry trees are just putting out their flat flower umbels. I’m pleased that the swarms of midges that plague this stretch in the summer have not yet arrived.

At the end of the warm stretch is a shady grove of eucalyptuses. (There are lots of different types; I have no idea which these are.) Eucalyptuses

 are Australian transplants that just can’t get enough of California. The unusual seedpods, spicy fragrance, and strippy bark were so much a part of my childhood that I was surprised to learn that these trees were non-native and invasive. This park has never made any claims to be a pristine native habitat, and honestly, the shade slips deliciously over us after the warmth of the hill.

We have one other major stop on this walk, and that’s Maisie’s Peak, 1100 feet above sea level. Alas, the view isn’t all that impressive. Up this high, you can see miles of suburbia at the boundaries of greenness, the cement quarry on the other side, the Moffett Field hangars all the way out, ribbons and ribbons of gray highway stretching into the distance. The wide open space seems like it goes on forever when you’re in it, but it ends all too soon.

Heading back, I see some flowers I have never seen before. (You’d think that in 12+ years, I’d have seen everything at this park, but it all changes so quickly and there are enough trails that I’m sure I miss a lot.) These big 1.5-2″ four-petaled flowers have me stumped. This is where Google images and my gads of flower guides come in. I’ll let you know when I have an answer.

This was an easy walk, no more than 2-3 miles, so we leave feeling energized and ready to take on the human world again. I hope you enjoyed our excursion!

I don’t think you need to love plants and wild things to be an environmentalist, but it’s a core part of why I care about this planet. Do you have a favorite hiking spot? What’s growing there  right now?

Looking at Trees, Part 1: Winter

Time for a confession: I don’t actually hug trees. I’m not a big hugger to start with, and trees are scratchy and unyielding. Many have ants trailing up the grooves, baby snails hatching in knots, sap dripping down in slow motion. I may not be a literal tree hugger, but I am a tree lover and an enthusiastic tree watcher.

My tree book collection has exploded in the past year with natural histories, field guides, and photography books. In the space of a year, I have started to look — really look — at trees for the first time. I was originally going to write this post in the fall, when trees still had leaves. But winter is actually a very good time to start looking at trees. Leaves can be so distracting. Without them, you can see the bones underneath and appreciate the architecture.

Precise tree identification is probably best left to the experts, but it’s actually not very hard to get started with the basics. I’d like to share a little of what I know in hopes that the boring old tree outside your window will suddenly become a lot more interesting. My earliest tree lessons came from my mother, who gave me the names to eucalyptus, liquidambar, and mulberry trees early in my childhood. I’m grateful. (Incidentally, this post is only about broad leafed trees. I’m just not that into conifers yet, other than the wonderful coastal redwoods I grew up with. Sorry.)

Looking at Branches: Opposite vs. Alternate

If you can categorize a tree as having opposite branches, you can rule out a whole lot of other possibilities. Only a few tree families have opposite branches, and there’s a handy little mnemonic to help you remember which: Damp Horse (dogwood, ash, maple, paulownia, and horse chestnut). Winter is a good time to check out whether your neighborhood trees have opposite or alternate branches. Be careful, though. While black ashes form clear, dark crosses across the sky, you’ll have to look closer with most other trees. Also, alternate trees will have the odd opposite pair, and vice  versa. If you see many pairs of opposite branches, however, you’re probably on to something.

See the way the branches grow out opposite each other to form Vs or crosses? This is an ash tree.

Looking at Fruit/Seeds

Botanists have lots of different names for different types of fruit (drupes, pomes, arils…). I don’t know all of them yet, and you really don’t need to in order to pick out several of the major tree families.

Acorns = Oak (Quercus)

Only oaks bear acorns, so if you see green acorns on a tree or brown acorns beneath one, you’re looking at an oak. Oaks are a crazily diverse family of trees. This photo shows an oak with smooth, deeply lobed leaves, but there are also oaks with sharp lobes (black oak), small spiny leaves (coast live oak), and even smooth, elongated oval leaves (holly oak). Most oaks lose their leaves in the fall, but live oaks stay green year round.

As a very rough generalization, most mature oaks are stout trees with irregular (non-symmetrical) crowns and gnarled branches and trunks.

Paired Samaras = Maple (Acer)

I probably don’t have to tell you what a maple leaf looks like, but not every tree that has maple-like leaves is actually a maple (see plane trees, next), and if that wasn’t enough, there are also maples with leaves that look like ash leaves (box elder). However, all true maples have paired sets of winged seeds, which are called samaras. They spin like helicopters when you drop them, and I’ve always thought they were an instance of awesome design by nature.

Maples include sugar, silver, and Japanese varieties. Many maples turn beautiful colors in the fall, especially on the east coast. Branches are opposite, and as far as I know, all maples are deciduous.

Soft Seed Balls = Plane Trees / Sycamores (Platanus)

 If you see a bare winter tree with camouflage like bark (big gray, white, tan, and/or orange splotches) and 1″ seed balls hanging down, especially near the top of the tree, you’re looking at some sort of plane tree (sycamores in American English). The seedballs are a little spongy and surprisingly light for their size. If you pull one open, you’ll find that it’s filled with white fluff, and the brown outside is actually formed of lots of tiny seeds packed together. They’re kind of like inside-out dandelion puffs.

Plane trees have big maple-like leaves, but good luck trying to tap one for syrup. At least in my area, they are one of the most common street trees.

Wicked Spiky Seed Balls = Sweetgum / Liquidambar (Styrax)

There are probably other trees that produce round, brown seed balls. But the sweetgum is so common and distinctive that I thought I’d point it out to you. The sweetgum has star-shaped, vaguely maple-like leaves that turn brilliant colors even in mild California autumns, and after they’re all gone, spiky seedballs hang down from the bare branches like ornaments. Unlike the plane tree’s seed balls, these are spiked all over and very hard. The seeds are dispersed through holes in the ball, leaving the spiky structure intact. These things decompose very slowly — amid the brown ones of this year, you can often see grayer, smaller seed balls of previous years.

Whew! I could go on for a while, but I don’t want to be a bore. I noticed today that some of our street trees (Bradford pears) are already putting out new buds. California trees live in a state of perpetual confusion about when they’re supposed to do what. In the spring proper, I’ll bombard you with information about flowers and leaves.

Have you ever taken a close look at your hardworking and underappreciated street trees? What kind of trees are around you?

Take a Virtual Wild Plant Walk

My mother’s postage-stamp suburban garden was my childhood laboratory. Some days, I think I missed my calling as a botanist: I collected nectar from honeysuckle flowers, one drop at a time. I ground up four o’clock flowers to make dyes, opened up their powdery seeds, nibbled at mallow cheese wheels, popped the papery seed capsules of hummingbird vines, soaked gardenias in water to make perfume, and tried to make glue out of the sticky, bitter, milky sap in rattlesnake weed. (As an adult, I found out that a number of these things are actually toxic, so it’s a good thing my mom didn’t have oleanders in her garden.)

I’m still into plants. Kevin picked up some edible wild plant guides for me (including the classic Stalking the Wild Asparagus by Euell Gibbons), so my interest has taken a new direction lately. I don’t think it’ll come down to having to forage for food, but I kind of like having that option if things get really bad at some point. And for me, learning about plants is one way I acknowledge, respect, and appreciate the world around me. There are others, but this is one of my favorite ways.

Come on a virtual guided plant walk with me! Let’s go to my favorite open space, the Fremont Older Open Space. I’ve been walking the trails in this park for almost ten years at this point, have seen it in every season, and know its seasonal and yearly rhythms. If you can have a friendship with a place, I have one with this preserve. I’m no expert, but I’d like to introduce you to some of the denizens of this park.

It’s July, so things are bone dry, despite a few days of unseasonal rain last month. There are rolling golden hills with thigh-high dried grasses that have gone to seed, green coast live oaks with deep roots and twisted trunks, and the hardier, tougher wildflowers that have replaced April and May’s delicate vetches, lupines, and golden poppies. Under the hot California sun, mounds of leafy green poison oak are already turning red. The insects buzz around you; the shrill whine of a cloud of midges, the cicadas off in the grasses.

Here’s a flash of yellow in the bushes to one side as we head up the hill: it’s sticky monkey flower.

Sticky monkey flower is a member of the Mimulus family. It concentrates sodium chloride from the soil so it has a salty, bitter taste. Native Americans used to use it as a salt substitute. (At least according to Wikipedia.)

Down by the creek, we come across these pretty green leafy plants. Don’t touch! It’s stinging nettle and has lots of tiny hollow hairs that contain histamine. Incidentally, stinging nettle is fine to eat as a salad green once it’s been lightly steamed. I’ve also heard it used for medicinal teas. Just be sure to pick it with gloves.

And here’s another creekside plant that bites back:

Wild blackberries have sharp thorns all over the vines. The leaves often come in threes, but you can tell it’s not poison oak because of the thorns (well, and the berries). Most parks have policies against foraging, so we sample a berry each — they really do have a sweet, wild perfume compared to farmed blackberries — and move on.

Once we leave the creek, things are looking a bit withered. All the purple thistles (actually an invasive species) have dried out and died this year, and I’ve noticed that it’s a bad year for manroot, a curling vine that produces big, eyeball-sized green spiky balls. I think the late rains and cold spring might have affected its growth. Maybe next year.

Moving on…here’s something interesting: towering 5′ clusters of white flowers on skinny green stalks with fern-like leaves. Notice the purple spots on the stems. Kinda pretty, isn’t it?

It’s poison hemlock. Same stuff Socrates succumbed to. (And yes, it’s an invasive species in California.) Every part of this plant is extremely toxic, and to make things worse, it can look like edible family members such as parsnips and wild carrot (Queen Anne’s Lace). The primary toxic alkaloid is coniine, a neurotoxin that causes muscular and respiratory paralysis, and then death from lack of oxygen. Since I’m pretty sure you don’t want to have a taste, let’s leave the hemlock and keep going.

Getting a little tired and hot? Let’s duck into the woods. The California buckeyes are still in flower — big 1′ long pinkish white spikes that have a delicate, sweet scent. You can often smell them before you see them around a bend in the path. Buckeyes have distinctive palmate leaves (leaves spread out from a central point, like fingers on a hand) and are related to chestnuts. Native Americans used the poisonous nuts to stun fish in the water to make them easier to catch. The buckeyes are blooming late this year due to the cool weather; usually they’re all done by early June.

Not everything in this park is poisonous. Just to the side of the buckeye is a nice patch of miner’s lettuce, an edible leafy green that miners ate to get their vitamin C. (It was either that or get scurvy.) It’s said to taste a bit like spinach, but I have to confess I’ve never tried it. The small white flowers grow on top of round, disk-shaped leaves, making it highly recognizable. If you look closely at the image, you’ll see some blackberry leaves underneath. Watch out for those thorns!

I could go on, but you might be bored at this point. If you’re not, it really doesn’t take much to learn how to identify at least some of the plants around you. A local field guide helps, but just as often as not, I’ve had luck typing things like ‘spiky purple flower’  into Google image search.

This is your mission, should you choose to accept it: get outside and learn something about the plants near you. Tell me what you discover and enjoy being outdoors!

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