Thinking About Harry Plants While Feeling Harried

Many words exist that describe hairs or harriness of plants.  Here are some that I found:

trichome
pubescent
tomentous
villous
indumentum
wooly
pilose
colleter
felted
floccose
glochid
hirsute
hispid
hispid
penicillate
puberulose
sericeous
strigose
stellate
arachnoid

How are hairs adventageous to plants? In Johnson (1975)'s  review, he concludes that the propensity to make hairs is quite widespread in plants, and suggests that the ability to make hairs is probably genetically available to most plants.  Perhaps in line with the Gould Lewontin's famous essay "The Spandrels of San Marcos", Johnson (1975) seems to hint that hairiness in leaves and stems could be just a correlational effect, a trait that exists more due to the need for root hairs than for any function to leaf and stem hairs.

On the other hand, Johnson (1975) reviews quite an array of advantages that have been proposed for leaf and stem hairs.  Hairs on leaves may reduce water loss from leaves.  Hairs change the reflectance of a leaf, and also the wavelenghts of light absorbed by a leaf.  Taking this information together, hairs on leaves could affect leaf temperature, photosynthesis, and water retention.  Hairness of plants may make them less palatable to predators (Johnson, 1975).  Hairy leaves are not only harder to eat and chew, but they may be less ideal for laying eggs or even for the growth of fungi and bacteria (Johnson, 1975).  Finally, Johnson (1975) suggests that hairs on leaves increase the surface area and may influence excretion of gases, fluids, inorganic or organic solutes.

Today I post a picture of lamb's ear, Stachys byzantina .  This plant is loved by many gardeners and by my children.  Wikipedia suggests that it is native to the middle east.  This plant is a member of the Lamiales or Mints.  Like other members of the family, Stachys byzantina has a tubular flower, five-fused petals, and a corolla that is bilabiate and appears to have two lips.  The bilabiate shape of flowers has evolved more than once so the shape of the flower is perhaps not the best way to identify family.  There are many interesting chemicals and oils found in members of the Lamiales, and likewise members of this family are often aromatic.  The leaves of members of the Lamiales (including Stachys byzantina ) are often opposite, and the stem is often square.  The style of many Lamiales flowers arises from a depression in the ovary.

Click on this picture for a bigger view of Stachys byzantina

Life is busily speeding along, and I can knot afford to spend more than a brief moment on untangling hairy plants; I'm just too harried!   (Comb on, there must be better puns for this topic!)

Gould, Steven J and Richard C. Lewontin. 1979.  The spandrels of San Marco and the Panglossian paradigm: A critique of the adaptationist programme. Proceedings Of The Royal Society of London, Series B, 205: 581-598.

Johnson, Hyrum B.  1975.  Plant pubescence: an ecological perspective.  The Botanical Review 41: 233-258.



Burr Cucumber and Early Successional Environments

Where are all the blogs that I planned to write?  They are lost in the rush of my life.  I appear to have personality traits that are advantagous only in an often-disturbed, early successional environment. I am sloppy, rushed, and eratic.  These traits work fine when the critical deadlines are yesterday, but don't work so well for long term endurance and planning ahead.

I am choosing to blog today about Burr Cucumber.  It seemed to be appropriate that I should blog about an early-successional plant that does well in disturbed environments, and that seems to appear out of nowhere, rush through its plant-life and disappear just a quickly, unable to survive any serious competition or bad weather.

Burr Cucumber is in the genus, Sicyos . How is that pronounced? I wanted to say it "sick", but upon going to this site: I found that the c sounds like an "s".  At the end of the summer, burr cucumber suddenly appeared on our back porch, and in what seemed like just a matter of days, it was lush and big and taking over.  While the plant grew very well, at the first bit of frost, it appears to have died.  (In contrast, our garden pepper plants are still  hanging in there!)  The burr cucumber seems to have more speed than stamina and endurance. The genus belongs in the Cucurbitaceae or Gourd family.  Like some other members of this family it has hairy stems, palmate leaves, and a propensity to climb.  Although the burr cucumbers are not edible, its relatives, the  pumpkins and squashes (both Cucurbita pepo)and cucumbers (Cucumis sativus) are edible.

I haven't keyed out the plant in my backyard, but I suspect that the species growing there is Sicyos angulatus - which is a native weed, and some sites regard it as invasive to fields of nonnative crops. 

This weed reminds me of several topics that I emphasize in my classes.  I bring up climbing plants when I talk about convergent evolution.  Tendrils are one of  many homoplastic climbing traits that plants have evolved repeatedly to solve the same problem:  the need to raise the photosynthetic leaves above the nearby competition.  This plant also displays traits that are advantageous in an early-successional environement:  grow fast and put most of  your energy into growth and reproduction and none into storage; this plant is an annual.  It has not saved any resources to survive the winter; it has reproduced and died.

My life seems to be favoring the "do things quickly"strategy - or at least I feel a pressure to focus more on short-term results than long-term solutions.  And on that note, I redirect my attention away from the pleasant long term goal of learning more about plants, and return my attention to getting a cup of coffee so that I can work faster, burn out sooner, and meet those immediate deadlines of my often disturbed daily routine.

Pictures of Sicyos on my back porch:

Flowers Without Petals: Wind Pollination is Derived in Angiosperms

Flowers without petals: While walking the dog this summer, I tried to take note of all the flowers that are in bloom but which don't have petals. I took pictures of birch, oak, and hickory flowers; last summer I managed pictures of the willow flowers too (and with the help of some students labeled male and female plants along a trail.) The general belief is that the catkins that these plants have are probably, in many cases, examples of convergent evolution. Furthermore, all these flowering plants probably evolved from insect-pollinated ancestors. Wind-pollination is a derived characteristic in flowering plants, but an ancestral characteristic in gymnosperms. Mixed pollination system are probably more common than people realize & the paper below makes me want to keep an eye out for those mixed systems! (New word: ambophily)

Culley, T. M., S. G. Weller, A. K. Sakai. 2002. The evolution of wind pollination in angiosperms. TRENDS in Ecology & Evolution 17:361-369.

I had my daughter tap on the male cones of a gymnosperm in the cemetery while I tried to take a picture. You can kindof see the pollen poofing out. 

The gymnosperms have been wind-pollinated for a long time! In flowering plants, wind pollination is more recent & has evolved repeatedly.

I hope your allergies aren't acting up.

Pollen Sculpturing

Pollen Sculpturing:

The exine or hard outer part of a pollen grain (and for that matter other spores) is often very pretty - some species are known to have distinctive textures, spikes, and indentations. Here's a link to a nice picture on Wikipedia:

https://upload.wikimedia.org/wikipedia/commons/a/a4/Misc_pollen.jpg

Why the fancy surface texture? One possible reason is that those crevices and spikes help chemicals "stick" to the pollen grain. What kinds of chemicals are needed on the surface of a pollen grain? In some cases, chemicals that prevent self-pollination. Today, I am thinking about another common sticky substance found on the outside of pollen grains called pollenkitt. I googled "kitt and German", and it appears that "kitt" is a German word for "putty". That seems right to me. Pollenkitt is a sticky putty that holds pollen grains together.

If a plant is wind-pollinated, then it is better if the pollen grains don't stick together & so wind-blown pollen is expected to have less pollenkitt than animal-carried pollen.

This summer, I found myself surprised by the fact that Forsythia plants and Ash trees are in the same plant family. Forsythia is insect-pollinated and Fraxinus americana (white ash) is wind-pollinated. I wondered if they differ in their pollenkit content as predicted by their pollination systems? I did in fact look at the pollen grains of both under a microscope and was delighted to see that Forsythia pollen had visible pollenkitt and Ash pollen did not. Here's are a few picture (my own pictures):

Possibly because it is important for pollen grains to be coated with chemicals, some plants have evolved very beautiful pollen grains with very interesting surfaces. Maybe this is a stretch, but I can't help but wonder if pollenkitt may be one evolutionary reason why pollen grains are so beautiful.

On a side note: A few years ago I found this link to the work of an artist whose passion for pollen sculpturing has led her to make pollen sculptures.

http://www.jogolesworthy.com/wpimages/wp7ff3213b_05_06.jpg

Supplementary reading:
Dobson, Heidi E. 1988. Survey of pollen and pollenkitt lipids-chemical cues to flower visitors? American Journal of Botany 75: 170-182.

Botany in a modified world - Is every plant worthy to know?

A Quaker philosophy that I try to hold near to me is that every person has an inner light.   Maybe a similar thought can be applied to every plant:  the idea that every plant (or every organism, regardless of taxonomic group) can tell a worthy story.

We live in a world of modified landscapes.  I recall one of my mentors telling me that there are no truly pristine place left on earth.  All habitats are modified.  Another memorable experience was walking through the "old growth" portion of Cook Forest with a naturalist visiting from Germany who kept commenting that the forest was over-browsed by deer, and questioned how the forest could be accurately referred to as "old growth".  Even the least disturbed places on earth have been modified by humans; habitats aren't what they were before there were 7 billion people on earth.  Global climate change will touch every "pristine" place.

I wandered through a local nursery last week, looking at the "native" trees - catalpa, oaks, and even witch hazel.  Although these trees represent native species, the ones at the nursery were still varieties that had been chosen by humans interested in particular traits.  I suspect these garden center/nursery trees harbor different genes from a population genetic standpoint than the original wild populations of the same species 300 years ago.  If I buy one of those trees (which I was thinking of doing) will I be continuing the trend of diluting the locally-adapted gene pools?

I find it overwhelming.  The cup seems more than half empty when my mind tries to grasp the extent that humans have modified the world, and especially when I glimpse of my own role in the process.  It's like catching a view of yourself in the back of a spoon- distorted and ugly; my overuse of resources, my failure to curb and set greater limits on my children's consumer temptations, and so on and so on.

Looking at things from the half-full standpoint is so important.  In a previous post I commented about learning from unredeeming places.  I think I am an unredeeming person at times, but I'm going to go with the belief that all plants and all people, even those most modified & even mass produced by humans, like corn, are still fascinating, and worthy of study, if for no other reason than the love of learning / the joy of gaining basic, unapplied knowledge.

There are two genera of plants that I want to share today.  Each genus has both a native and a horticultural relative that occur in my area.  In both cases, I learned the horticultural variety before I ever discovered the native species, and I think I appreciated the native ones even more because I was already familiar with a close relative.

Impatiens

Walmart sells an abundance of these flowers. They might be hybrids or just highly bred individual species - I really don't know.  They are so commercialized that it is easy to look down one's nose at their artificial colors and their universal commonness.  And yes, they are even a bit invasive; I recall seeing the garden varieties that had snuck into the rainforest in Costa Rica while I was part of an OTS class, but they are interesting plants even despite being so modified by humans.  I especially love to turn the flowers over - the garden varieties often have spectacularly long nectar spurs.

There are two native species in my neck of the woods. Superficially and from a distance, the garden Impatiens look quite different from the native ones, but close up and with the eye of a botanist, some similarities stand out - especially the fantastic nectar spurs.

Impatiens pallida

Impatiens capensis

Spiraea

Most of the year the horticultural varieties (which seem to me to be mostly hedge bushes) in the Spiraea genus are nondescript - almost invisible in their plain background green color and short shrubby stature. Here's a picture of a Spiraea bush blooming near my house. The flowering bush pictured below is probably native to Asia and really doesn't "belong" in Pennsylvania.

Yesterday we kayaked at a state park in Pennsylvania, and lo and behold I was introduced to a native member of this genus. This pretty native Spiraea grows in wet areas.

Spiraea tomentosa

If I were a plant, I fear I would probably be a modified garden variety, mass-produced and similar to so many other plants found in the aisles of Walmart garden center - I am a native want-to-be but I have given in too much to the seduction of modern technology and mass culture. Furthermore, my genes are most certainly transplanted to Pennsylvania through a long history of human colonization.

Maybe the cup isn't quite so empty though, maybe even modified people, modified landscapes and modified plants have a story to tell.  And while it is admittedly a stretch, I think that knowing the modified plants might help us appreciate the native ones even more.  I suppose you could also argue for the potential for restoration of these modified places and things.

Maybe I am justifying and thinking way way too much & maybe I should just simply enjoy every plant and every person without a lot of deep thought!!

Actaea racemosa and racemes

I joined my daughter on a one-day trip to a Girl Scout camp.  While the girls were climbing the rock wall, I was looking for wildflowers in the lovely forest there.  We saw many large flowering Actaea racemosa whose common name is Black Cohosh and Black Snakeroot.  This plant has a long (6 inches or more) raceme of white flowers.  The leaves are divided (compound) and most of the leaves arise from the base of the plant, but some are alternate along the stem.  The mass of multiple stamens spewing out of each flower give you a clue to the plant family - a basil Eudicot, Rununculaceae.

This plant is in the same genus as White Baneberry (Doll's Eye) which is a distinctive poisonous plant of Pennsylvania.

As I tried to key out this plant - I had to distinguish between racemes and spikes.  In a raceme, each flower has a stem or stalk.  In a spike, the flowers are stalkless. For more information visit this wikipedia page:   http://en.wikipedia.org/wiki/Spike_(botany)

Here are some pictures of this interesting plant!

Basal Eudicots

Basal Eudicots

The phrase "Basal Eudicots" may be outdated & a paraphyletic concept but it seems to help me mentally organize plants.   

Having lots of stamens is probably an ancestral characteristic in the angiosperms.  (Wind pollination is probably derived!)

Characteristics:  Many stamens, actinomorphic (radially symmetrical) flower, generalized pollination where many insects could pollinate as they roam around the flower, many separate carpels in individual flowers (true in the Caltha but not in the Podophyllum)

Ranunculales is one of the plant orders that is considered a Basal Eudicot & you can see the loads of stamens on these pretty flowers.  They are also nice and symmetrical, and you can even see the multiple carpels on the top picture.

Culley, T. M., S. G. Weller, and A. K. Sakai. 2002. The evolution of wind pollination in angiosperms. Trends in Ecology and Evolution 17:361-369

Friedman, J., & Barrett, S. C. 2009. Wind of change: new insights on the ecology and evolution of pollination and mating in wind-pollinated plants. Annals of Botany, 103(9), 1515-1527.

Caltha palustris

Podophyllum peltatum

Ostrya virginiana and Carpinus caroliniana

Hop Hornbeam, Ostrya virginiana

American Hornbeam, Carpinus caroliniana

Carpinus caroliniana

Common names of plants can cause confusion.  There are at least two trees in the eastern United States that are called "hornbeams" - these two tree species are also both sometimes referred to as "ironwood".  These two tree species are closely related (Betulaceae) and tend to be small to medium sized trees with very similar toothed simple leaves, and wood that is dense and hard.  My dog walk route takes me by both species, and the pictures above were all taken this summer (the two bottom picture I took this week).  On top is the "hop hornbeam" or Ostrya virginiana named because the fruit looks a bit like a completely unrelated species of herbaceous plants, called "hops" that are fermented to make beer. Ostrya virginiana has bark that is flaky and peels.  The bottom two pictures show Carpinus caroliniana which has very smooth bark and whose fruits are a little less compact (bottom left picture).  I like the name "musclewood" or "blue beech" for Carpinus caroliniana better than the common name "American hornbeam" because it tells a little bit about the bark.

I enjoy these two species even if their names are confusing. Not only are they lovely native trees that are often overlooked, but they were the plants that first gave me an image of what beer hops might look like.  Beer hops are Humulus lupulus, and they belong in the Cannabaceae.

Welcome to Phloem Here To There

Today's Plant Trivia:  mangos and poison ivy belong to the same plant family.
I am a biology teacher and a mom, and this is my first post on a blog of my own.  My daughter recently explained to me that mangos are in the same plant family as poison ivy (Anacardiaceae).  How did she learn this fact?  She learned it playing Fruit Ninja on her iPod.  I waffle about modern technology; how should I feel about my daughter and me wasting attention, time, and energy on mindless computer activities like Fruit Ninja?   In a world of so many detrimental temptations, I guess I will still try to value every opportunity to learn, even if that opportunity comes from time wasted with a cartoon fruit sensei.  This blog is one of those opportunities to learn: a place for me to post my daily musings on plants.  I would like to learn more about the plants that I see on my daily dog walk. I would also like to learn more about plant families and their characteristics.  Obviously the best way to learn about the plants around me would be to stop typing and step outside, but I think that we are all sometimes stuck in place for real or imagined reasons, and just like the Fruit Ninja game and my daughter, maybe we should grab every opportunity to learn, even if the opportunity arises from an unredeeming place.   Please feel free to post comments and to join me in this virtual adventure to learn more about plants.