Category Archives: Poisonous

Plant of the day: marsh zigadene (death camas)

Growing alongside a meadow stream are many spikes of pale flowers. This is marsh zigadene, or Toxicoscordion micranthus. A few long, linear leaves sit unobtrusively at the base of the plant, which is decked with several dozen creamy white blossoms. The six-petalled flowers have a small yellow spot at the base of each grooved petal, and a short tight cluster of stamens with oversized anthers.

Marsh zigadene is a native that is usually found growing in damp places, often near serpentine, according to the Flora of Marin. It’s common in this county but is rare elsewhere.

The common name for the several similar-looking species in the Toxicoscordion genus is “death camas.” These species are another example of highly toxic beauty. I have always known these plants as Zigadenus species, but they were recently moved to a different group (something that is always happening in the botany world – it can be hard to keep track!). They are still listed in most floras under the old name, but are in online databases under the new name.

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Filed under Native, Plant of the day, Poisonous, Rare

Plant of the day: poison hemlock

With lacy leaves and delicate flowers, this plant doesn’t look like a deadly killer. But it is. This is the same plant that is fabled to have poisoned Socrates, and is the bane of ranchers since it can kill undiscriminating cows (it’s also responsible for “crooked calf disease“). There’s no antidote. So – admire this one from a distance, but don’t eat it, crush it, or take any other liberties. The root is the most poisonous part (unnerving, since it’s part of the inviting-looking carrot family!)

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Conium maculatum isn’t native to California, but it is found throughout most of the state, often in open or disturbed places. Plants can grow to more than six feet tall, and have many flat umbels of lacy white flowers. Its similar-looking cousins, water hemlock, are also poisonous. But when I saw some on the open space above Mill Valley the other day, the lady bugs were having a wonderful time hanging out on the hemlock flowers!

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Filed under Invasive, Non-native, Plant of the day, Poisonous

Plant of the day: buckeye

It’s buckeye season – one of my favorite stages of spring. These spreading trees with their tall, pinkish-white spires of flowers can be seen along roadsides, streamsides, in mixed woodlands and even at the edge of pebbly beaches on Tomales Bay. I’ve seen Aesculus californica growing so close to the water that the lower branches were draped with streamers of dried eelgrass.

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This lovely tree is unique to California, and can be found across much of the state. It has loads of character, with knobby, gnarled trunks and wide palmately compound leaves. It leafs out during the winter, offering cool shade on hot days into the early summer, and then it goes dormant. In the fall it drops beautiful shiny chestnut-colored nuts (ok, actually they are “capsules” since the hard exterior contains several seeds). I like to gather them and use them for decoration. But don’t eat any! They are toxic, known to depress the nervous system, cause abortions in cattle and be toxic to bees. Native Americans would use extract of the seed topically (for hermerrhoids?!). In tough times the seeds were sometimes eaten (after careful preparation to leach the poison out). Buckeye also provided food in a different way: pouring a ground-up powder of the seed into a stream would stupify fish for easier catching!

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Filed under Good for gardens, Medicinal, Native, Plant of the day, Poisonous

Plant of the day: foxglove

Tall spikes of white or purple flowers are bursting like flares across Marin. This is the season for foxglove, another striking-looking invasive. Native to all parts of Europe, it has now colonized much of North America, where it appears to prefer the coastal areas to the heartland. You can find it in from Alaska to Mexico, and on much of the east coast as well. Digitalis purpurea can grow to be taller than a full-grown person and is quick to colonize areas that have been disturbed such as road sides, logging or building sites.

Foxglove is also highly toxic so don’t eat it!! Small amounts have been known to be fatal. Some of its other names give you a clue that this is a bad idea: Witches’ Gloves, Dead Men’s Bells, Bloody Fingers, and Fairy’s Glove just name a few. Yet in its noteworthy history, Digitalis was also used as a medicinal plant by herbalists. They were on to something: extracts from the plant are now used pharmaceutically to treat congestive heart failure. As much as I appreciate folk remedies, this is one I’m glad the scientific establishment has gotten involved with; messing around with a plant that supposedly killed some kids who drank the water from a vase containing foxgloves seems like a bad idea!

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Filed under Invasive, Non-native, Plant of the day, Poisonous

Plant of the day: poison oak

How about an easy one for a Monday! Common and important, unless you want to itch. Poison oak is easy/hard to identify, depending on how experienced you are in looking at plants. The leaves can range in color from dark green to light green to reddish, but they always have a glossy shine and another quality as well, one that’s distinct but hard to define. The leaves look… slightly luminous. Tender. As if, were you crazy enough to nibble on one, it would have a pleasant delicate texture.

The flowers of poison oak are small, inconspicuous, and not usually in bloom, so the leaves are what to look out for. These always come in groups of three, and they have a smooth surface, the veins only showing lightly and the surface not haired or spined. The edges are gently lobed or scalloped – to varying degrees, but they are neither straight nor serrated (like the edge of a bread knife). This helps you rule out other common plants, like blackberry, that some people confuse for poison oak. Once you get all those features down, really the only thing that looks similar are the leaves of a young true oak tree before it has grown tall.

The Latin name is easy to remember as well (even though I had forgotten it). Toxicodendron diversilobum. Intuitive, right? Toxic leaf with diverse lobes. Thanks John Torrey, Asa Gray, and Edward Greene who did the naming. Torrey produced the Flora of North America in the 1800s, and Gray helped him out. And how do I know they named our toxic friend, a newbie may ask? It says so right on all the official listings of the species. Check the names after the italicized species name on the above link: you’ll see Torr. and A. Gray, who did the original naming, along with Greene, who came along later and made some change – I’m not sure but maybe he is responsible for the “Toxicodendron”, since I seem to remember poison oak was a “Rhus” when I first learned it. Anyway this convention is called an author citation, with the namers being the “taxon authors“.

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Filed under Botany basics, Native, Plant of the day, Poisonous