Chaparral Yucca Seeds, and a Guest

My last post was about Chaparral Yucca, which is blooming in the Santa Monica Mountains right now.  A  few days after writing the post I was exploring Red Rocks Park in Topanga.  This park takes its name from the sculpted sandstone outcrops that rise from the Santa Monica Mountains.

Wind and water sculpted sandstone ledges

Wind and water sculpted sandstone ledges

Like most of the Santa Monica Mountains, this is a dry area, but it is relatively low elevation and nestled in a canyon, the bottom of which has an infrequently running stream and some lovely oak and sycamore trees.

The side slopes are home to the usual assortment of coastal chaparral plants, but the relatively low elevation, slightly greater water supply, and marginally cooler temperatures means that the plants are on an ever-so-slightly different flowering cycle.

Down here some of the Chaparral Yucca (Hesperoyucca whipplei) is still blooming, but other plants are well into the seed setting stage.

Chaparral Yucca seed pods slowly ripening

Chaparral Yucca seed pods slowly ripening

Each of the thorn-like stubs on the branches was a flower.  As you can seen a small percent of the flowers survive to form seed pods.  This year, this is a good crop, in other, wetter, years more might make to this stage.

The pods look like the offspring of a pickle and a ping-pong ball.  Green and slightly warty, divided into three chambers and about the size of a comfortable throwing stone.

Chaparral Yucca seed pod close-up

Chaparral Yucca seed pod close-up

As with the flowers, reaching them is a bit tricky because the basal rosette is composed of lance-shaped leaves crowned with needle tips.  Tips that only seem more aggressive and more prone to break off in your legs as the leaves dry in the increasingly hot summer sun.

Gathering these seed pods was an important activity for many of the coastal tribes as the seeds are edible and nutritious, and unlike the flowers and stalk, the dried seeds can be stored for a long time either whole or ground into flour.

At the moment the seeds are not-yet dried, but are still edible and tasty.

Chaparral Yucca seedpod cross-section

Chaparral Yucca seedpod cross-section

The seeds are flat and black or dark brown, and the capsules look very much like iris or lily seed capsules.  When fully ripe and dry the capsule splits open, disgorging the disk-like winged seeds that flutter to the ground in the frequent coastal breeze.

The green portion of the pod is extremely bitter, so it is best to separate the seeds from the pods for consumption.

The remains of the pods can last for several years in the dry climate.  They look a little like small loofahs hanging on to the dessicated flower stalks.

Chaparral Yucca dried seed pod

Chaparral Yucca dried seed pod

Chaparral Yucca grows in exposed areas in defiance of the sun and shallow soils.  This year even these hardy plants have few blooms and many of the other flowering plants here either didn’t bloom or did so quickly and finished quickly.  Despite the harsh conditions of this year, in some of the darker, damper areas a few plants still show their flowers.

In a little gully, well off the trails, I came across several blooming Scarlet Larkspur (Delphinium cardinale) plants.

Scarlet Larkspur (Delphinium cardinale) still blooming in a shady spot

Scarlet Larkspur (Delphinium cardinale) still blooming in a shady spot

Advertisements

Chamise – a key chaparral plant

The chaparral ecosystem in California is comprised of a dense and diverse collection of small to mid-sized woody shrubs.   It covers the hills in a shallow cloak of gray-green vegetation just thick enough to soften the contours of the land, but not to hide them.  In some places the chaparral is dense and thick, so much so that it is nearly impossible to penetrate it, other places it is sparse and low.  Animal trails riddle the chaparral and the bones of the land show through with a dramatic abruptness.

Sandstone outcrops above a chaparral covered hillside at Red Rocks State Park in Topanga

Chaparral grows primarily in dry, hot areas, as such the plants have a number of moisture saving adaptations that are most easily seen in their leaves which tend to be either small or waxy, or both in many cases.  The ecosystem is surprisngly diverse in both plants and animals, but despite this there are a small handful that are common from Mexico through most of California and that, taken together, could be considered to be the background matrix of chaparral plants.  Sage (Artemisia) and Ceanothus both are broad genus level plants with many individual members.

These plants are common in the chaparral, and taken with another extremely common plant, Chamise (Adenostoma fasciculatum), comprise what I think of as the matrix plants for the California wide chaparral.

Chamise (Adenostoma fasciculatum) flowers are small and clustered in tight bundles at the tips of the branches

Chamise, also known as greasewood, is in the rose family and produces clusters of small white flowers that look much like another rose family genus, Spiraea, which includes hardhack and meadowsweet.  The flowers set seed and dry on the branch, remaining affixed to the stalk for several seasons after blooming.

The leaves of Chamise are needle-like, clustered in little bundles called fascicles, the word the scientific name derives from.  On the whole, the plant looks something like a cross between rosemary and juniper with shredding bark, gnarled limbs, and and regularly placed leaf clusters.

Old Chamise plant on a ridge in the Santa Monica Mountains

Like many chaparral plants Chamise seeds require fire to germinate.  This ensures that the seedlings will be able to take advantage of the temporary increase of nutrients and open sunlight in the plant’s early stages of growth.  Estimates of the longevity of Chamise vary, but range from 100-200 years.

Chamise is not generally considered to be good browse for animals, but it is common to find extensive patches of heavily browsed plants.  In some places the browse is so heavy that the bushes look like sculpted hedges, in other places they look like carefully trimmed bonsai trees.

Browsed Chamise branches

When it has not been browsed Chamise produces a relatively dense growth of vertical shoots.  Over time many of these will die, with the dead stalks being retained by the plant.  Some estimates of the total volume of retained deadwood on old plants reaches 60-70%, greatly adding to the potential combustibility of the Chamise.

Young Chamise branches

California Buckwheat (Eriogonum fasciculatum) can sometimes be mistaken for Chamise by the casual eye, but the leaves are broader and flatter and the flower structure is very different.

California Buckwheat (Eriogonum fasciculatum)

Chamise is found primarily in California, though northwest Mexico and western Nevada also host populations of this plant.  Within California it is found in nearly all of the chaparral habitats as is shown on the digital Jepson Herbaria hosted by UC Berkeley.

Chaparral types with Chamise

This is a tough plant.  It grows with little water, on hard, rocky soil, and can even grow in serpentine soils, a soil type that kills many plants.  Many people do not like Chamise due to its flammability, but it is an excellent erosion control plant, provides cover for a number of birds and small animals, and serves as a last resort browse as well.

It is not the only chaparral plant by any stretch, nor even the most typical in any given area, but it is the one I have seen in the most places through California.

Dispersal & Reid’s Paradox

The distribution of organisms in the environment is a particularly interesting subject.  We know that individual  representatives of the different kingdoms have specific requirements for establishment and growth.  We know this at an almost intuitive level and we apply this knowledge daily when we amend soils for our gardens, move houseplants into or out of the sun, and make sure our pets are fed and watered.  If we need more tomato plants, we go to the store and buy young ones or seeds and plant them, likewise we buy puppies, kittens, or fish for our homes, taking them with us when we move from place to place.  We rarely ask the question of how living creatures move about in the absence of humans.  How they disperse.

Fleabane species – note the dandelion-like seed heads

This is a problem all living things face, and they all solve it in slightly different ways.  Obviously, for mobile creatures, birds, reptiles, fish, mammals, insects, and all their cousins, this can be handled in a relatively straightforward fashion by simply getting up and going somewhere else.  Clearly there are particular variations on the theme.  Red Efts in New England are born in the water, stay there for a time, move onto land as non-breeding adolescents, then return to the water as breeding adults.  The majority of them don’t travel far, but a few adults find themselves in a different body of water than they started in, thus slowly expanding the range of the species.  Yes, legs are helpful.

Red Eft (Notophthalmus viridescens) in its adolescent dispersal stage

In earlier posts I have mentioned how some insects spend most of their life hidden from us, entering their highly visible state only to breed and find new territories.

It has long been recognized that our understanding of how plants, fungus, and all the traditionally non-mobile creatures disperse is poorly understood and very, very important.  In 1899 Clement Reid introduced what is now known as Reid’s Paradox in his marvelous book, The Origin of the British Flora.  Reid’s Paradox is more formally known as “Reid’s Paradox of Rapid Plant Migration”, an unwieldy, if accurate title.  Simply put, the paradox is that every measurement we take of plant seed dispersal indicates that range expansions and colonization of new areas should take place extremely slowly, but everywhere we look plants have colonized new areas far, far faster than all predictions indicate is possible.  By orders of magnitude in some cases.

Reid recognized this problem when trying to calculate how long it would take oak trees to colonize Britain once the glaciers left.  There was a tremendous mismatch in where oaks were and where they should have been.  In modern times this mismatch has been expanded to a wide variety of other species and, despite advances in dispersal calculations, we don’t really have a good answer for it even now.  We lump it under the heading “long distance dispersal” and leave it at that.  I will return to this.

With fungus the dispersal question is a bit easier to understand.

Reishi (Ganoderma lucidum) fruiting bodies on a Hemlock tree

Two fungi of the same species meet and produce mushrooms (the sexual reproductive organ), scattering billions of spores smaller than dust particles that drift on the wind or in the water.  Except that fungi are really strange and ancient and have developed some special techniques for dispersal (EDIT:  Slime Molds have been removed from the fungal kingdom.  Now they are considered to be a polyphyletic group of protists representing convergent evolution from several origins.  A large branch of the slime mold group is closely related to amoeba).

Setting aside mobile slime-molds as a special case, the solution to dispersal that fungus use is one of numbers, astounding numbers, unbelievable numbers.  Only a very small portion of the released spores will disperse any great distance and an even smaller portion of the spores will germinate, but when you are dealing in the tens of billions even a small percentage can be a large number.

This, with some variation is the same answer to dispersal plants use, it’s a numbers game.  If a tree has a seed producing lifespan of 90 years and produces thousands of seeds each year and only 99.9% of the seeds never travel more than 100 feet from the tree that’s ok.  If the tree is living there, conditions are likely good, so it makes sense for most of the seeds to stay near home.  That 0.1%, well, who knows what odd event will carry the seed beyond that 100 foot (or whatever is is for that species) radius?  Storms and animals are common agents of long distance dispersal, as are humans now.

Plants are crafty though, they weigh the odds.  They may time the release of seeds to favorable environmental conditions.

Hop Hornbeam (Ostrya virginiana) seeds in their hollow sheaths

Hop Hornbeam (Ostrya virginiana) produces a dangling cluster of separate seeds, each individually packaged in its own balloon-like capsule.  Over time these seeds break loose and fall to the ground, similar to how grass seeds break from the rachis and fall to the ground when disturbed.  These seeds fall during winter, landing on the snow and blowing across the landscape, coming to rest in small hollows that also trap water and nutritious debris during spring melt.  Birch trees use this technique as well, blowing across the snow like grains of sand in a storm, as, to a lesser degree, does American Basswood (Tilia americana).

American Basswood (Tilia americana) seeds on snow

Another crafty plant technique to aid in dispersal is to hijack animals.  This is not much of a stretch for them, they already hijack animals for reproduction via pollination, but the ingenuity and range of techniques by which plants co-opt animals is truly astounding.  It is the kind of thing that really should, if you think about it, make you question who or what is actually in charge.

Phoresy is when one organism uses another to disperse.  Hitching rides on animals is a common version of phoresy plants employ.  It  is an extremely selfish and cheap way for plants to hijack animal legs or wings.  Seeds may have hooks, barbs, or be sticky, and the animals get no reward for helping the plant.  If plant times this right it may latch onto a migrating animal that may carry the seed hundreds or even thousands of miles.

A more targeted technique is to bribe the animal.

Lowbush Blueberries and Rock Polypody fern

Fruits (like the blueberry in the background of the image above) are sacrificial bribes for animals, like free drinks at a casino.  Often the fruits are targeted to specific animals or classes of animals.  The colors and smells let birds and beasts know when the fruit is safe to eat (meaning, when the seeds will survive a passage through the animal’s digestive system).  Just as with flowers, specific colors and odors are targeted at specific animals or suites of animals.  Certain plants have been very successful in hijacking humans for their purposes.

Also, notice the developing spores on the fern frond.

In some cases the plant simply sacrifices a portion of the seeds themselves so that a few may survive.  Oaks are a classic example of this.  Woodpeckers, blue-jays, chipmunks, and squirrels will cache acorns in a variety of places like leprechauns with pots of gold.  Some of these caches will be forgotten and will sprout.  This is why, in some areas, you may find 3 or 4 oak trees growing from a rock-pile all joined at the base.  Most likely they were separate seeds in a single food cache.  Again, oaks games the system by slowly dropping seed production year after year, then mast fruiting, producing an overabundance of food, far more than the now decreased animal population can possibly eat.

Wind and water are effective distributors as well, maples, coconuts, dandelions, and mangroves all use one or another of these techniques.  In most cases seeds don’t travel far, but in rare occurrences wind or water will carry seeds tremendous distances, and all it takes is that one or two times.

Right now the question of long distance dispersal and Reid’s Paradox is experiencing a revival in light of climate change.  Tree species in New England are moving north rapidly, and whole populations of plants and animals are moving away from the equator rapidly as well.  Others are climbing up or down mountains depending on whether temperature or moisture is the limiting factor.  If we want to know what the future holds we need to understand these action better than we currently do.

This hardly does justice to the complexity of methods and techniques used for dispersal, but it opens the door.

Canada Geese and goslings

Blue-Eyed Grass, diminuitive irises

From California to New England, from Alaska to Texas there is a small, easily overlooked wildflower that is blooming now and will continue to do so for several more months, depending on where you are of course.  The flowers of this plant are small, only a little more than a centimeter across have six petals, a yellow center, and are often blue in color, hence one of the common generic names, Blue-Eyed Grass, although there are yellow and white variations.  To see them clearly you have to get close, crouching or laying on the ground.

Common Blue-Eyed Grass (Sisyrinchium montanum)

You can see from the photo that the leaves of this diminutive plant are broad and flat, much like the leaves of the grass it grows amongst.  In Vermont there are several variations of this plant, Sisyrinchium montanum being the most common, hence the name, Common Blue-Eyed Grass, which is, unfortunately, not tremendously imaginative.  When it is not flowering it’s easy to see why it might be mistaken for a grass, it has a similar leaf shape and is of a similar height to the grass it grows amongst.  The flowers clearly set it apart though.  Petals are little flags to attract insects, birds, and in some cases lizards or mammals to the flower for pollination for which they are rewarded with nectar.  Grasses have no such need, like willows, poplars, and pines they rely on wind to distribute their pollen and petals are a hindrance and a waste of energy for a plant that uses wind rather than animals for pollination.

Wind pollinated grass flowers with Blue-Eyed Grass flowers in the background

Sisyrinchium, the Blue Eyed-Grasses are tiny irises.  The Iridaceae family is widespread and often used as ornamental plants in gardens or in bouquets.  The larger irises have showy, ornate, soft flowers that fold and flow in complicated shapes, looking little like the small, robust Sisyrinchium flowers.  In the wild, the larger irises tend to grow in places that are either damp, shady, or both.  The Blue-Eyed Grasses live in harsher regions, open meadows, occasionally on rocky ledges, the edges of open areas, in short, places that can get hot and dry.  This may partially explain their small, robust stature.

Like other irises Sisyrinchium has inferior ovaries, this is not a commentary on the quality of the ovaries, it is a botanical term meaning that the ovaries are below the flower rather than the flower surrounding the ovaries.  These little plants produce globular three-part capsules about the size of a BB filled with numerous little seeds.

Blue-Eyed Grass with immature seed capsules

I grew up looking at these little flowers on the wildflower rich coastal prairie of Northern California, but just a few days ago I discovered something new (to me) about them.  They are active, they open their flowers for the day and close them for the night.  I tried my hand at a time-lapse of a flower opening.  It’s a bit rough, but you get the picture.

Blue-Eyed Grass flower opening animation

I love finding out things, being surprised by life, experiencing the unexpected, and encountering things I do not know.  I’m glad that these little irises reminded me that such a small, seemingly mundane thing can be interesting and exciting.