My Carrion Flowers

In April of last year, a box of stem cuttings arrived in my mailbox. They were sent to me by a friend in Colorado called Sandra (you may know her from one of her many ventures: Greenwoman Magazine, Greenwoman Publishing, Flora’s Forum, etc.). Sandra’s carrion flower had bloomed that spring, a stinky but delightful occasion. In her excitement, she asked if I would be interested in growing some carrion flowers of my own. Not one to turn down the chance to try my hand at cultivating something unusual, I gladly accepted her offer of a few cuttings sent via Priority Mail. Six cuttings arrived shortly thereafter, and upon reading through some instructions on the internet, I nestled them into their new home and hoped they would put down roots and stay a while.

carrion flower cuttings

There are several species of plants that are referred to commonly as carrion flower. The plant parts I received from Sandra are in the genus Stapelia (family: Apocynaceae or dogbane family), also known commonly as African starfish flower. There are around 100 species in the genus Stapelia, and they all originate from tropical and southern Africa, mostly in arid regions.

Stapelias are short-lived, low-growing, perennial succulents. Their stems typically stand erect and are produced along stolons (above ground runners), creating a tight clump of stems that appear cactus-like. Each stem has 4-6 flattened vertical flanks, giving it a cross or star shape when looking down from the top. On the outside edges of the flanks are a series of rudimentary leaves protruding from tubercles (wart-like growths), giving the stems a spiny appearance. The stems are usually green but can also be red or mottled with red or purple.

The flowers of Stapelia are the real show. They are produced at or near the base of the stem and have a star-shaped corolla with five fused petals that come to sharp points. The corolla has a wrinkly look and is often hairy, especially along the margins. Flowers can be variations of red, brown, yellow, and purple. In some species they can reach up to 18 inches wide. It is a unique looking flower, but even more unique is its scent. Because Stapelia flowers are pollinated by flies, they emit the scent of rotting animal flesh, an odor that flies can truly appreciate. In fact, flies can be so deceived by the appearance and scent of the flowers that they occasionally lay their eggs on or near them, expecting them to be a food source for their emerging larva.

Stapelia variegate (photo credit: eol.org)

Stapelia variegata (photo credit: eol.org)

Stapelia is easily propagated, especially by stem cuttings. Allow cuttings to dry in a cool, shady location for 48 hours and then stick them in a well-drained potting soil mix. Water moderately (preferably from below by placing the container in a tray and then filling the tray with water). Cuttings should root easily. All six of mine did.

Keep Stapelia in a sunny or mostly sunny location. If you live in USDA hardiness zone 9 or above, you can grow Stapelia outdoors. Otherwise, keep it indoors near a window that gets lots of sun. The main thing you will have to worry about is stem rot due to over watering. Grow Stapelia in a well-drained soil mix, water from below, and allow soil to dry out between waterings in order to avoid this.

Stapelia variegata (photo credit: eol.org)

Stapelia variegata (photo credit: eol.org)

As for me and my carrion flowers, like I said earlier, all six cuttings rooted. I transplanted one of them. Of the five left in the original pot, one rotted a couple weeks ago and another rotted during the writing of this post. The remaining ones still look healthy, but none of them have grown much since they rooted. The main problem I am having is that my house does not let in much sunlight. What appears relatively bright to me is probably cave-like to my carrion flowers. Until I remedy that situation, they may not grow much, they could continue to rot, and they probably won’t flower any time soon. However, if anything changes and I do get a flower out of them, I will make it a point to let you know. And Sandra will be proud.

stapelia today_edit

 

Trees Are Good For Your Lungs

Trees help reduce air pollution. They do this primarily by pulling gases (like ozone, sulfur dioxide, and nitrogen dioxide) into their leaves and then diffusing them and/or chemically altering them so that they are no longer a direct threat to humans. They also intercept particulate matter, trapping it on the surfaces of their leaves until the wind comes along and blows it away or the rain comes around and washes it into the soil. Trees are filters in this sense, reducing the health threats of our polluted air.

But didn’t I just report on the contribution of urban trees to air pollution via their production of volatile organic compounds? Yes I did. And that remains a possibility; however, according to a study recently published in the journal, Environmental Pollution, the presence of trees is a great benefit to human health despite potential risks. More research is necessary of course, but the consensus so far is that having trees around is a net positive.

Alnus glutinosa, European Alder (photo credit: wikimedia commons)

Alnus glutinosa, European Alder (photo credit: wikimedia commons)

There have been many studies on the relationship between trees and air quality, but little is known about the extent to which human health impacts are avoided and the related money that is saved as a result of air pollution mitigation by trees and forests. With the aid of computer simulations, researchers at US Forest Service and The Davey Institute used 2010 Census data, tree cover maps from the 2001 National Land Cover Database, US EPA’s BenMAP program, and other data to seek answers to these questions. Their analyses – focused at the county level – involved the 48 contiguous United States.

According to their study, trees and forests removed around 17.4 million tons of air pollution in 2010, which resulted in a health care savings of $6.8 billion. 850 human deaths were avoided, and incidences of acute respiratory symptoms were reduced by 670,000. Ozone and nitrogen dioxide experienced the greatest decrease, while the removal of ozone and particulate matter resulted in the greatest health value. Air pollution removal was greater in rural areas compared to urban areas simply because there is more rural area in the US than urban area; however, the removal of air pollution was found to be more valuable in urban areas due to differences in population density. Resulting health benefits and savings are quite dramatic considering that air pollution removal by trees was only found to improve air quality by about 1%.

There were many things left out in this study though, and the researchers acknowledge this. First of all – as stated earlier – trees have the potential to contribute to air pollution. They emit volatile organic compounds which can result in ozone formation, they can reduce wind speeds which concentrates pollutants, and they produce pollen which is a direct contribution to air quality and a major health issue for those with serious allergies.  But trees reduce air pollution in indirect ways as well. For example, by shading buildings, trees can reduce energy demands which results in decreased power plant emissions and a reduction in air pollution.

Quercus sp., Oak Tree (photo credit: wikimedia commons)

Quercus sp., Oak Tree (photo credit: wikimedia commons)

Trees can also be negatively affected by air pollution. When particulate matter collects on leaf surfaces, photosynthesis is compromised, limiting a tree’s ability to take gaseous air pollution into its leaves. Urban trees are stressed in additional ways. For example, trees growing near sidewalks, driveways, and roadways deal with serious soil compaction and are often not receiving optimal amounts of water, which can limit their ability to mitigate air pollution. Thus, environmental factors should be considered when determining the relationship between trees and air quality.

This study was conducted at the county level. The researchers acknowledge that more precise predictions could be obtained if analyses were conducted at a finer scale. “Local-scale design of trees and forests can affect local-scale pollutant concentrations.” So, the number of trees, their concentration and configuration, the length of the growing season, the percentage of evergreen trees vs. deciduous trees, etc. all play a role in the extent of air pollution reduction.

While limitations to the study abound, the researchers assert that this initial analysis gives “a first-order approximation of the magnitude of pollution removal by trees and their effect on human health.” Future studies will provide more accurate approximations, but for now I think it is safe to say that trees are good for our health and worthwhile things to have around.

Boise National Forest

Boise National Forest

This study focused mainly on health issues of the respiratory variety. The positive psychological benefits of plants have been observed in separate studies, and our also worthy of our consideration when determining the health benefits of trees and forests.

Drought Tolerant Plants: Blue Sage

If you are considering installing a drought tolerant garden on your property or including more drought tolerant plants in your landscape, one plant that should come standard is blue sage. Its silvery-green foliage, large, abundant, purple-blue flower stalks, and attractive mounded shape, make it an excellent feature in any water-efficient garden bed.

salvia pachyphylla_edit 1

Salvia pachyphylla is in the mint family (Lamiaceae). It has several common names which it shares with several other plants: blue sage, Mojave sage, rose sage, mountain desert sage, giant-flower sage. For this post we will refer to it as blue sage; however, if you’re looking to purchase it, make sure to verify the botanical name. Blue sage is a subshrub that can grow up to 3 feet tall and 3 feet wide. It tends to remain smaller – around 1-2 feet tall – in its native habitat. It is found in the southwestern states of the United Sates on dry, rocky slopes and flats at elevations between 5,000 – 10,000 feet. The leaves are oppositely arranged on a square stem and covered with fine hairs that lay tightly against the leaf surface giving the foliage its silvery appearance. Like all other sages, the leaves of blue sage are highly aromatic.

salvia pachyphylla foliage_edit

The flowers appear in compact clusters on spikes that extend upward from the branches. The inflorescences can be several inches long. They have numerous large, purple bracts that appear in a whorled pattern along the spike. The violet-blue flowers are small but prolific and appear between the bracts surrounding the stalk. Flowering occurs throughout the summer (July-September in its native range). The flowers attract droves of pollinators including bees, butterflies, and hummingbirds. Blue sage is especially beneficial to native pollinators. In fact, while taking photos for this post, I noted that the flowers were being visited by several bumblebees. Its benefit to pollinators is another great reason to include this plant in your landscape.

salvia pachyphylla_edit 2

Blue sage is a very drought tolerant plant. Once it is established it requires only occasional watering throughout the summer in order to keep it looking good. It performs well in a variety of soil types, but like most drought tolerant plants it is best placed in well drained soil. Heavy soils can be amended by mixing in things like sand, lava rock fines, and compost at planting time. It prefers full sun and is winter hardy to USDA hardiness zone 5, especially if planted in an area where the soil is relatively dry throughout the winter. Blue sage is a long lived plant and can be kept in shape by cutting back the spent flowers in the fall. The folks at Plant Select recommend planting blue sage with, among other things, penstemon, coreopsis, and creeping veronica.

Photos were taken at Idaho Botanical Garden in Boise, Idaho.

14 Botanical Terms for Flower Anatomy

I like to know the names of things. Certainly I don’t have to know what everything is called in order to appreciate it for what it is, but that appreciation deepens when I understand it better. Scientific exploration helps us discover the workings of the world around us, and through that exploration comes the naming and describing of things. The names are largely arbitrary apart from the fact that they help us keep track of the descriptions associated with the discoveries. Calling things by name and knowing how to describe them not only increases our awareness of the natural world but can also give us greater appreciation for the larger picture and our place in it all. With that I introduce a new series of posts concerning botanical terms.

It’s mid-summer now (at least in the northern hemisphere) and flowers abound, so this first Botanical Terms post will help us become better familiar with flower anatomy. [I'm also releasing this post while the Botanical Society of America convenes for its annual conference in my current hometown - Boise, Idaho - so it seems fitting]. Of course, as soon as I began looking into the subject of flower anatomy, I realized very quickly that, like so many other things, it is incredibly complex. First of all, in the larger world of plants, not all produce flowers. Non-vascular plants don’t. And within the category of vascular plants, non-seed producing plants don’t make flowers either. Within the category of seed producing plants, there are two groups: gymnosperms and angiosperms. Angiosperms produce flowers; gymnosperms don’t. Even though that narrows it down quite a bit, we are still dealing with a very large group of plants.

The complexity doesn’t stop there, of course. Memorizing the names of flower structures and recognizing them on each flowering plant would be easy if every flowering plant had all of the same structures and if all structures existed on each flower. However, this is not the case. Depending on the flower you are looking at, some structures may be absent and some may have additional structures that are not common ones. Also, some plants have inflorescences that appear as a single flower but are actually a collection of many smaller flowers (or florets), like plants in the sunflower family (Asteraceae) for example. Regardless, we are going to start with basic terms, as there are a large number of flowering plants that do exhibit  all or most of the following basic structures in their flowers.

flower anatomy

Pedicel and Peduncle: These terms refer to the stem or stalk of the flower. Each individual flower has a pedicel. When flowers appear in groups (also known as an inflorescence), the stalk leading up to the group of flowers is called a peduncle.

Sepal and Calyx: Sepals are the first of the four floral appendages. They are modified leaves at the base of the flower that protect the flower bud. They are typically green but can be other colors as well. In some cases they may be very small or absent altogether. The sepals are known collectively as the calyx.

Petal and Corolla: Petals are colorful leaf-like appendages and the most familiar part of a flower. They come in myriad sizes, shapes, and colors and are often multi-colored. Their purpose is to attract pollinators. Many plants are pollinated by specific pollinators, and so their petals are designed to attract those pollinators. The petals are known collectively as the corolla.  

Stamen, Anther, and Filament: Pollen is produced in a structure called an anther which sits atop a filament. Collectively this is known as a stamen. Stamens are considered the male portion of the flower because they produce the pollen grains that fertilize the egg to form a seed. Flowers often have several stamens, and on flowers that have both male and female structures, the stamens are found surrounding the female portion.

Pistil, Carpel, Stigma, Style, and Ovary: The female portion of a flower consists of a stigma (where pollen grains are collected), a style (which raises the stigma up to catch the pollen), and an ovary (where pollen is introduced to the ovules for fertilization). Together this is known as a carpel. A collection of carpels fused together is called a pistil. Just like with stamens, flowers can have multiple pistils.

Start learning to identify floral structures on flowers like rugosa rose (Rosa rugosa). (photo credit: eol.org)

Start learning floral anatomy on flowers with easily recognizable structures like the flowers of rugosa rose (Rosa rugosa). (photo credit: eol.org)

Flowers are small art pieces, worthy of admiration in their own right. However, recognizing and exploring the different floral structures can be just as enthralling. The structures vary considerably from species to species, each its own piece of nature’s artwork. So, I encourage you to find a hand lens (or better yet a dissecting microscope) and explore the intimate parts of the flowers around you.

Feeding the World with Microbes

Back in the mid 1900’s, after the tragic days of the Dust Bowl in North America, new agricultural techniques and technologies were developed and distributed in the name of food security. These developments included higher yielding plant varieties, synthetic fertilizers and pesticides, and advancements in irrigation and other management practices. This period in time was termed the Green Revolution, and it truly was a remarkable time. Agricultural advancements that came out of this period have helped us feed the world and stave of starvation for millions of people. Today, issues of hunger and starvation are political problems, not necessarily agricultural ones. However, the human population continues to grow, and today’s 7 billion people is projected to reach up to 10 billion (or more) in the coming decades. The world’s best farmland is either already in use, degraded, or being used for other things. This means that we must find a way to feed a growing population with the diminishing farmland that is available. We may be producing enough food now (despite the distribution problem), but will we be able to produce enough in the future? The hunt for the Green Revolution 2.0 is on.

“According to the [UN's Food and Agriculture Organization], most of the growth in production…has to come from increasing yields from crops. Selective breeding doesn’t seem to be offering the types of dramatic yield increases seen in the past. Meanwhile, genetic engineering has yet to lead to any significant increase in yields. Now, many scientists are saying that we’ve been looking at the wrong set of genes.”

These are the words of Cynthia Graber, author of an article that appeared last month on PBS Online’s NOVANext entitled, “The Next Green Revolution May Rely on Microbes.” In it she explores the argument that increasing future yields will depend on better understanding the soil’s microbial community and its complex interaction with the plant community. The big question: if microbes can be artificially bred – the same way virtually all agricultural plants have been – might they help us increase food production?

Microbial life in the soil is incredibly diverse. In one teaspoon of soil, there can be billions of individual microbes including bacteria, fungi, protozoa, algae, and nematodes. Our current understanding of soil life is extremely limited, akin to our understanding of outer space and the depths of the oceans. That is because, as stated in Graber’s article, “perhaps 1% of all soil microbes can be grown in a petri dish, the conventional model for such research.” This limits our ability to study soil microbes and their interactions with other living things. We do, however, acknowledge that the interactions between the roots of plants and soil microbes is incredibly important.

Fruiting Body of an Ectomycorrhizal Fungus (photo credit: eol.org)

Fruiting Body of an Ectomycorrhizal Fungus (photo credit: eol.org)

One major player in these interactions is a group of fungi called mycorrhizae. “Mycorrhizal fungi cannot survive without plants, and most plants cannot thrive without mycorrhizal fungi.” It is a symbiotic relationship, in which the fungi offer plants greater access to water and nutrients, and plants feed sugars derived from photosynthesis to fungi. Recent advancements in genetics have allowed researchers to better analyze the genes in microbes like mychorrizal fungi and determine the functions of them. Through selective breeding, microbes can be produced that will offer even greater benefits to plants, thereby increasing yields. For example, some microbes help plants tolerate heat and drought. Isolating the genes that give microbes these abilities, and then breeding these genes into other microbes might allow for a wider palette of plants to receive this kind of assistance.

In researching this article, Graber followed a Swiss researcher to Colombia where he was testing lines of mychorrhizal fungi on cassava. The fungi were specifically selected to increase a plant’s access to phosphorous. This is one of many experiments that are now under way or in the works looking at specially bred microbes in agricultural production. It’s an exciting new movement, and rather than spoil too much more of Graber’s article, I implore you to read it for yourself. Share any comments you may have in the comment section below, and expect more posts about plant and microbe interactions in the future.

Cynthia Graber appeared at the beginning of a recent episode of Inquiring Minds podcast to talk about her article. I recommend listening to that as well.

Hundreds of Japanese Plants Threatened with Extinction

Life has existed on earth for at least 3.5 billion years, and during that time there have been five mass extinctions. Currently, we are in the middle of a sixth one. The major difference between the current extinction event and others is that this one is largely human caused, which is pretty upsetting. However, knowing that detail has its upside: if humans are the drivers of this phenomenon, we can also be the ones to put on the brakes.

Biologists have spent the last several decades tracking the current mass extinction, endeavoring to come up with a list of species that have the greatest risks of extinction, as well as lists of species that are at less of a risk, etc. The problem is that factors leading up to extinctions are diverse, and available data for making predictions is lacking, especially temporal data. Recognizing this information gap, researchers in Japan set out to better determine the extinction risk of Japanese flora. Using data from surveys done by lay botanists in 1994-95 and 2003-04, they were able to calculate a trend which indicated that, under current circumstances, between 370 and 561 plant species in Japan will go extinct within the next 100 years.

photo credit: wikimedia commons

photo credit: wikimedia commons

The methods for this study, as described in the findings which appeared last month in PLOS ONE, involved dividing Japan into 3574 sections measuring around 100 square kilometers each and covering about 80% of the country. More than 500 lay botanists tallied the numbers of species that were found in each section during the two time periods. 1735 taxa were recorded, and out of those, 1618 were considered quantifiable and used in the analysis.

Japan is home to a recorded 7087 vascular plant taxa. Historically, the extinction rate of plant taxa in Japan has been around 0.01% per year. According to this study, over the next 100 years the extinction rate will rise to between 0.05 and 0.08% per year. Researchers are organizing a third census in the near future in order to monitor the actual extinction rate and better determine the accuracy of this prediction.

Data collected in these censuses was also used to evaluate the effectiveness of protected areas and determine the need for improvements and expansions. Natural parks cover 14.3% of Japan, but only about half of that area is regulated for biodiversity conservation. The researchers found that protected areas do help to reduce the risk of extinctions, but that their effectiveness is far from optimum and that even expanding protected areas to cover at least 17% of the nation (a target set at the recent Convention on Biological Diversity) would not effectively gaurd threatened plant species from extinction.

In their conclusion, the researchers advise not only to expand protected areas but to improve the “conservation effectiveness” of them, and “to improve the effectiveness of them, we need to know the types of pressures causing population decline in the areas.” They go on to list a few of these pressures, including land development and recreational overuse, and suggest that management schemes should be developed to focus on specific pressures.

Japanese Primrose, Primula japonica (photo credit: eol.org)

Japanese Primrose, Primula japonica (photo credit: eol.org)

One thing I found very interesting and encouraging about this study was the recruitment of lay botanists in collecting data. As stated in the findings, “Monitoring data collected by the public can play an essential role in assessing biodiversity.” I am excited by the growing citizen science movement and hope to see it continue to expand as more and more people become interested in science and eager to add to this body of knowledge. In fact, I consider the term “awkward botany” to be synonymous with citizen, lay, and amateur botany. That is precisely why I chose it as the title for my blog. So, in short, expect more posts involving citizen science in the future.

You can read more about this study on John Platt’s blog Extinction Countdown at Scientific American.

 

Corpse Flower Blooms Again

It is not often that a plant in bloom makes headlines, but that is precisely what happened last week when another corpse flower bloomed at Missouri Botanical Garden. Amorphophallus titanum, commonly known as titan arum or corpse flower, is a rare species, both in cultivation and in the wild. It also rarely flowers, and when it does, the bloom only lasts for a few short days. It has the largest known unbranched inflorescence, and its flowers give off the scent of rotting flesh. For all these reasons, it is understandable why a blooming corpse flower might make the news.

Titan arums naturally occur in the western portion of an Indonesian island called Sumatra. Their future is threatened because they occur in rainforests that are currently being deforested for timber and palm oil production. Deforestation is also threatening the survival of the rhinoceros hornbill, a bird that is an important seed distributor of titan arums. Today there are a few hundred titan arums in cultivation in botanical gardens throughout the world. They are a difficult species to cultivate, but their presence in botanical gardens is important in order to learn more about them and to help educate the public about conservation efforts.

Amorphophaulls titanium, titan arum (photo credit: eol.org)

(photo credit: eol.org)

Titan arums are in the arum family (Araceae), a family that consists of around 107 genera including Caladium (elephant ears), Arisaema (jack-in-the-pulpits), and Wolffia (duckweeds), a genus that wins the records for smallest flowering plant and smallest fruit. Titan arums are famous for their giant inflorescence, which can reach more than 10 feet tall. The flowering stalk is known botanically as a spadix, a fleshy stem in the shape of a spike that is covered with small flowers. The spadix of titan arums are wrapped with a leaf-like sheath called a spathe. Upon blooming, the temperature inside the spathe rises and the flowers begin to release a very foul oder, similar to the smell of rotting flesh. This attracts pollinating insects such as carrion beetles, sweat bees, and flesh flies, which get trapped inside the sheath and covered with pollen. After a few hours the top of the spadix begins to wither, allowing the insects to escape, off to pollinate a neighboring corpse flower [the spadix includes male and female flowers, which mature at different times in order to prevent self-pollination]. Once pollinated, the flowers begin to form small red fruits which are eaten by birds. The seeds are then dispersed in their droppings.

The large, stinky inflorescence is not the only structure that gives titan arums their fame. They are also know for their massive single leaf, which can reach up to 20 feet tall and 15 feet wide, the size of a large shrub or small tree. All of this growth is produced from an enormous underground storage organ called a corm. The corms of mature titan arums typically weigh more than 100 pounds, with some known to weigh more than 200 pounds. Titan arums bloom only after the corms have reached a mature size, which takes from seven to ten years. After that they bloom about once a year or once every other year, depending on when the corm has accumulated enough nutrients to support the giant flowering structure.

Below are two time lapse videos of titan arums in bloom. The first is from Missouri Botanical Garden, and the second is from United States Botanic Garden.

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