Feeds:
Posts
Comments

Archive for the ‘Teaching & Learning’ Category

No, Can’t, Don’t

Posted in drawing, teaching & learning, Teaching & Learning on November 2, 2012|

When ArtPlantae participates in educational events, garden shows and other venues, I bring a traveling Guest Sketchbook with me and a sign that reads, “Please doodle in the Guest Sketchbook. Chicken scratch preferred. Words not necessary. Select any page. Thank you.”

All day long I invite people to doodle. Adults are the first to shake their heads no and to walk away. The usual response is “No. I can’t draw and I don’t doodle.” One man said, “Oh no. Not without a straightedge!”

The response I receive from children is very different. They are all over the sketchbook. Some return to draw again. Others lose track of time and space and draw for a long time. While most children respond in a positive way to my invitation, there have been some who have politely declined.

At an outdoor event where everyone is out enjoying a sunny day, having my invitation turned down is no big deal.

But what if you were using drawing as a learning tool for specific reasons and had a room full of students who groaned at the thought of having to draw for an assignment? What do you do then?

In Drawing Out the Artist in Science Students, science teacher Al Camacho, mechanical engineering professor Gary Benenson and Patricia Rosas-Colin, a graduate student in mathematics education have an answer to this dilemma. Their answer is quite simply, teach these students how to draw.

Not in an assertive “Draw or else!” sort of way, of course. But in a way that encourages them to become visual thinkers.

In their paper, the authors present five exercises designed to make students thoughtful and inquiring observers. Here I provide only a one-line description of each exercise. For all the juicy details, please see their paper.

In Camacho et al. (2012), you’ll find exercises about:

  • Sci-a-grams: What are they and how they can be used to demonstrate the value of simple sketches.
  • Basic Shapes – How to see shapes in everyday objects
  • Creating with Basic Shapes – How to create representational images
  • Information Through Labels – An exercise in communicating information
  • Diagram Design – An exercise in explaining how things work

You will also find in this paper a scoring rubric teachers can use to evaluate student drawings and assess student understanding.

The exercises presented in this paper do more than help students use drawing as a learning tool. They train students how to communicate information visually and equip students with a new way of thinking and expressing ideas (Camacho et al., 2012).

To obtain a copy of Camacho et al. (2012), you can buy this article online from the National Science Teachers Association (99¢).


Literature Cited
Camacho, Al and Gary Benenson, Carmen Patricia Rosas-Colin. 2012. Drawing out the artist in science students. Science and Children. 50(3): 68-73.

Read Full Post »

Need examples of how biology and art influence each other? Start here.

Posted in scientific illustration, Teaching & Learning on October 26, 2012|

The links between art and science are obvious to me and to you too, I am sure. The difficulty in making this case to others who may not share our interests is providing examples of how art and science work together. Pointing to illustrations in a field guide or a textbook is easy to do, however, if we do this too often, I feel we risk making the impression that science and art intersect only in academic texts. Searching for examples outside of academia requires travel to venues such as museums and art shows and, while definitely not a bad thing, time and resources limit how much traveling we can do.

Fortunately for us, Maura Flannery wrote Biology & Art: An Intricate Relationship, a wonderful article in which she features 22 artists and how they blend biology and art in their work. You can postpone your museum visits for a little while longer. Thanks to Maura, you only need to travel as far as your file cabinet for examples to help illustrate the fact that biology and art influence each other on many levels.

The artists featured in Flannery (2012) work with pencil, pen and ink, glass, clay, stainless steel, and even dung. Some keep nature journals, press plants, make prints with fish, create molecules, and use insects as art. You’ll even find examples of controversial bio-art in her article.

You may recognize the name of one of the artists Flannery writes about. Illustrator Jenny Keller made Flannery’s list because of the chapter she wrote about the value of sketching in Michael R. Canfield’s Field Notes on Science and Nature. Keller is a scientific illustrator and instructor in the scientific illustration certificate program at California State University, Monterey Bay. Keller’s sketchbooks are packed with information and are oh-so-inspiring. Actually, the word inspiring doesn’t cut it. I am going to borrow the word illustrator Dorothia Rohner used this past summer at the conference of the Guild of Natural Science Illustrators — “masterful”.

In keeping with our shared interest in plants, I will mention one more artist Flannery writes about in her article. Artist James Walsh discovered that many of the weeds growing in New York are native to the Arctic (Flannery, 2012). To bring attention to these plants, he collected them, studied them, pressed them and created an exhibition about his findings. A summary of the 2010 exhibition is still viewable online.

Flannery’s article is filled with fantastic examples and I recommend it as a reference to anyone whose interests are firmly planted in biology and art. Her article can be purchased online for $14 or obtained by visiting your local college library.


Literature Cited
Flannery, Maura C. 2012. Biology & art: An intricate relationship. 74(3): 194-197. The American Biology Teacher


More Examples of Biology & Art
To Maura’s well-researched list, I would like to add the following resources for your consideration:

  • Symbiartic: The Science of Art and the Art of Science
  • Science-Art.com
  • Member Gallery of the American Society of Botanical Artists
  • The Ask the Artist list located in the column to the right of this article. This list features the wonderful guests who have shared their work and who have taught us so much. Guests such as Gary Hoyle. Gary will be taking your questions through October 31, 2012. Have a question about museum exhibits, dioramas or the realistic plant models seen in museums? Ask Gary!

Also, don’t miss Maura’s article about imagery in scientific communication.

Read Full Post »

College Students’ Knowledge of Plants

Posted in teaching & learning, Teaching & Learning on October 19, 2012|

We have seen how experiences in informal botany education can improve the plant recognition skills in children. Today we take a look at how plants fare in the minds of college students.

In Botanical Knowledge of a Group of College Students in South Carolina USA, Gail E. Wagner evaluates student knowledge of crop plants, trees, flowers, weeds, vines and grasses.

Wagner’s sample population consisted of thirty-one 18-22 year-old college students. Sixteen interviewers helped Wagner conduct this study. Each interviewed two students. The students who were interviewed were selected by the interviewers themselves. Both the interviewers and the interviewees were undergraduate students at the University of South Carolina. The interviewers were enrolled in an ethnobotany course.

During this study, students were asked to create a list of plants for each of the categories mentioned earlier. Wagner (2008) marked entries as being “correct”, “wrong”, or “inappropriate”. Incorrect entries were plants listed in the wrong categories or were listed using general terms. Entries marked “inappropriate” were entries that were placed in the correct category, but did not meet other criteria outlined by the interviewers (such as plants growing outside of South Carolina) (Wagner, 2008).

Student responses were entered into a software program used for consensus analysis (see Wagner’s paper for details). Data analysis revealed:

  • Students were more familiar with crops, trees and garden flowers than vines, weeds and grasses.
  • 77% of students could identify local crops correctly
  • 50% of students could list at least one wildflower or weed correctly (“dandelion” was listed most often)
  • 35% of students could not list a grass. One of the students surveyed remarked, “I didn’t know there were different kinds of grasses” (Wagner, 2008)
  • 19% of students could not list a vine
  • 4% of students could not list a wildflower or weed

Wagner (2008) found that students could provide the most detailed plant lists for categories with which they were most familiar. She explains she is not surprised by students’ ability to correctly identify more crops, trees and wildflowers given the well-established fact that children in industrialized countries interact with plants less frequently, are exposed to many non-native plant species through urbanized landscaping, and “that most local flora is viewed from the window of a vehicle” (Wagner, 2008).

Gail E. Wagner’s paper is much more than an analysis of botanical knowledge. It provides interesting insights into sources of knowledge and how people categorize information. Wagner (2008) provides an interesting discussion about “direct”, “indirect” and “vicarious” knowledge. Citing research about how children experience nature, she explains that indirect knowledge comes from direct interaction with plants, that indirect knowledge comes from guided interactions (such as what can be found at botanical gardens), and that vicarious knowledge is the kind of knowledge one might acquire while surfing the Web or watching television.

To learn more about these topics and Wagner’s thoughts about designing studies to evaluate botanical knowledge, download a copy of her article by clicking on the link below. The article is free to download. The journal Ethnobotany Research and Applications is published online. Its contents are licensed under a Creative Commons Attribution 3.0 License.


Literature Cited

Read Full Post »

Using Dioramas to Teach Biology

Posted in Teaching & Learning on October 12, 2012|

When you see a diorama in a museum, do you give it a passing glance or do you stop to look inside?

If you stop to look inside, do you notice the animals first? The plants? What do you see? How do you make sense of the scene before you?

Michael J. Reiss and Sue Dale Tunnicliffe of the Institute of Education at the University of London evaluate dioramas and study how visitors react to them. In Dioramas as Depictions of Reality and Opportunities for Learning in Biology, they explain how these small “rooms with a view” can be used as a teaching tool in biology.

Reiss and Tunnicliffe (2011) evaluated dioramas at the American Museum of Natural History in New York, the Museum of Scotland in Edinburgh and the Natural History Museum in London. In their evaluation, they observed each diorama carefully and answered the following questions:

  • What is happening within the diorama?
  • What was the intention of those who designed and constructed the diorama?
  • What do visitors notice and discuss?

Their evaluation of dioramas was followed by a review of visitor comments collected from 163 conversations recorded at the Natural History Museum in London.

The authors found that dioramas enhance visitors’ observational skills, encourage inquiry-based learning and inspire visitors to become storytellers. Reiss and Tunnicliffe (2011) observed that when visitors stop to view a diorama, a specific sequence of events occurs. First, visitors identify the specimens in the diorama. Then they make comments about the specimens and interpret the scene before them by drawing upon their prior knowledge. This is followed by visitors asking questions about the scene and devising a story to describe what is going on in the diorama.

It is the storytelling aspect of dioramas that Reiss and Tunnicliffe (2011) say make dioramas good tools for learning in biology. The stories visitors create about the scene before them blend their observations with their own life experiences and this makes it possible for visitors to internalize new information. Reiss and Tunnicliffe (2011) feel museum educators need to guide visitors in the storytelling process because sometimes dioramas can tell the wrong story.

What do Reiss and Tunnicliffe (2011) mean by this?

While the authors value dioramas and the attention to detail that goes into their construction, they have some concern about the messages they send. Their specific concerns have to do with dioramas moving away from “actual reality” and their tendency towards “interesting presented reality” (Reiss and Tunnicliffe, 2011). The authors are concerned that dioramas:

  1. Depict animals doing more interesting things than they would be doing in real life.
  2. Present animals engaged in “unrealistically frequent acts of predation” (Reiss and Tunnicliffe, 2011)
  3. Show only examples of healthy and fit animal life.
  4. Do not include humans interacting with nature, therefore suggesting that humans are separate from nature.

Think about the dioramas you have seen. Do you agree with the concerns raised by Reiss and Tunnicliffe?

Share your observations and thoughts by joining the conversation with artist and museum consultant Gary Hoyle, this month’s featured guest. Today the conversation is about dioramas and the visitor experience.


Literature Cited
Reiss, Michael J. and Sue Dale Tunnicliffe. 2011. Dioramas as depictions of reality and opportunities for learning in biology. Curator: The Museum Journal.
54(4): 447-459

This paper can be purchased online for $35 or obtained by searching the stacks at your local college library.


Also See
Teachers view humans as separate from the environment

Read Full Post »

Informal Botany Education Can Improve Plant Recognition Skills

Posted in Teaching & Learning, teaching and learning on September 28, 2012| 2 Comments »

In the introduction to her research paper, Botanical Knowledge of a Group of South Carolina Elementary School Students, Chandra L. Cooper shares a quote by anthropologist Eugene S. Hunn in which he pronounces the extent of Americans ignorance of the natural environment.

His comment begs the questions: How ignorant are they? Can this be reversed?

Cooper addressed these questions, in part, by studying the botanical knowledge of a small group of elementary school children. To determine how much the students knew about plants and to determine if this knowledge could be improved through informal learning experiences, Cooper created a way to quantify the students’ prior botanical knowledge and created a three-month program in informal botany education whose aim was to improve students’ knowledge of plants.

Cooper’s research focused on how well a group of elementary school students could identify trees, flowers, weeds/wild plants, garden crops, vines, shrubs/bushes, water plants, house plants, grasses and “other plants” (Cooper, 2008), plants not included in the previous categories.

From December 2006 through May 2007, Cooper (2008) worked with children enrolled in a small elementary school located in rural South Carolina. The sample population (n=11) consisted of eight males and three females, age 9-12 years. Of the eleven students, data for ten were analyzed.

Cooper (2008) administered a three-part pre-assessment survey to determine students’ prior experiences with nature, their ability to name plants and to sort them into categories, and their ability to identify 60 species of plants shown in a slide show. For the post-assessment survey, students repeated the same tasks. They also responded to questions in a verbal interview conducted by Cooper.

The pre-assessment inquiries revealed that nine of the students had a vegetable or flower garden at home and that eight of them had experience performing yard work (Cooper, 2008). Pre-assessment surveys also revealed the children preferred outdoor activities over indoor activities, most had participated in recycling practices in their home, and that the students were able to identify at least two uses of plants (Cooper, 2008). When asked to list plants in the 10 categories outlined above, students listed an average of 10 trees, 6 flowers, 9 garden crops, and 3 weeds; their lists for plants in the remaining categories were very short, containing 1-2 items each (Cooper, 2008). When asked to identify plants in a slide show containing 60 species of plants (students were allowed to view the slide show at their own pace), students could on average identify 33% of the plants in the slide show, with all of them correctly identifying cotton, potato, rose, strawberry and bamboo (Cooper, 2008). Students could identify garden crop plants 70% of the time, multiple-use plants 60% of the time and wild plants 18% of the time (Cooper, 2008).

Following the pre-assessment surveys, students attended a three-month after-school program in which they participated in hands-on activities about plants and studies about plants in their local area (Cooper, 2008). Upon completing the program, students could list significantly more garden crop plants than they did in the pre-assessment survey (Cooper, 2008). They also listed significantly fewer shrubs/bushes, a development Cooper (2008) says can be explained by the students’ ability to better categorize plants as a result of their participation in the after-school program (see Cooper’s paper for a detailed review of student responses).

Post-assessment surveys also indicate this small group of elementary school students could identify correctly 55% of the plants in the slide show — up from 33% (Cooper, 2008). When analyzing the average number of correct responses made by students, Cooper (2008) found that students could identify correctly 91% of garden crop plants (up from 70%), 33% of ornamental plants (up from 15%), 42% of wild plants (up from 18%), and 80% of multiple-use plants (up from 60%).

The three-month program implemented by Cooper lead to an increased interest in plants and increased student ability to identify correctly various categories of plants. Student interest in plants was assessed during the post-assessment interviews. Enhanced student interest in plants was confirmed by the types of comments students made during the interview. Comments such as, “There are a lot more plants in the environment than I think, and I’ve just got to look closer” (Cooper, 2008).

Cooper’s results indicate that a program in informal botany education can lead to increased knowledge about plants and to an enhanced interest in the plant world.

Read more student comments about plants.

Download a copy of Cooper’s article by clicking on the link below. The article is free to download. The journal Ethnobotany Research and Applications is published online. Its contents are licensed under a Creative Commons Attribution 3.0 License.


Literature Cited
Cooper, Chanda L. 2008. Botanical knowledge of a group of South Carolina elementary school students. Ethnobotany Research and Applications. 6: 121-127. Web. <http://lib-ojs3.lib.sfu.ca:8114/index.php/era/article/view/166>
[accessed 28 September 2012]


Studies of Botanical Knowledge
In her introduction, Cooper (2008) discusses how the botanical knowledge of children in indigenous societies is greater than that of children in the US, in the United Kingdom, and in Switzerland. She cites studies reviewed previously in this column. Click on the links to these studies to learn more.

Read Full Post »

Drawings Reveal How Teachers View the Environment

Posted in drawing, environmental education, teaching & learning, Teaching & Learning on September 21, 2012|

Instead of exploring drawing and learning as it applies to young learners, today we’re looking at drawing, learning and teachers.

How teachers view the environment influences how they make meaning about it. To investigate how teachers view the world around them, Christine Moseley, Blanche Desjean-Perrotta and Julianna Utley field-tested a scoring rubric assessing teachers’ perceptions of the environment as revealed through their drawings. Their findings are discussed in The Draw-An-Environment Test Rubric (DAET-R), Exploring Pre-Service Teachers’ Mental Models of the Environment.

Drawings have been used as a research tool for many years because they provide insight into an individual’s beliefs and how they make meaning about the world around them (Moseley et al., 2010). Because there has been little research into teachers’ mental images of the environment and how these images influence how teachers think about the environment, Moseley et al. (2010) made this the focus of their research.

To make it easier to quantitatively assess teachers’ mental images as revealed through their drawings, Moseley et al. (2010) created a rubric that enabled them to assign a score to specific elements (or “factors”) in a drawing. The rubric they designed was used to evaluate pre-service teachers’ replies to two prompts in the Draw-An-Environment Test (DAET). Teachers were instructed to draw a picture of what they thought the environment was and then were asked to provide a written definition for the environment. The two prompts pre-service teachers responded to were “My drawing of the environment is ___” and “My definition of the environment is ___”.

Moseley et al. (2010) designed this study to address two research questions:

  1. Is the Draw-An-Environment Test Rubric a valid assessment tool?
  2. What mental models (i.e., images) do early childhood pre-service teachers have of the environment?

The quick answer to their first research question is, “yes”. The rubric they created is a valid and reliable assessment tool. A thorough statistical analysis of the DAET-R can be found in their paper.

As for their findings regarding their second research question…

One hundred eighteen pre-K to fourth grade pre-service teachers (average age 26.9 years) participated in this study. The participants were enrolled in senior level science and math courses.

The drawing portion of the DAET was evaluated using the DAET-R. The evaluation focused on “the degree of evidence in the drawings of interactions” (Moseley et al., 2010). Scores were assigned if a factor was present, if a factor was not present, if a factor interacted with other factors and if two or more factors interacted with each other (Moseley et al., 2010). The research team assigned “degrees of evidence” using a scoring system of 0-3 points, with the highest point score assigned to drawings in which “the participant was trying to indicate an interaction among factors with an emphasis on a systems approach to the definition of environment” (Moseley et al., 2010).

The drawings they received revealed that the pre-service teachers do not consider humans to be an integral part of the environment. Sixty percent of the participants completing the DAET did not draw humans in their pictures and only 31% drew humans interacting with the environment in some way (Moseley et al., 2010). The drawings also revealed the pre-service teachers’ lack of understanding about interactions occurring between factors in the environment (Moseley et al., 2010). Participants included many factors in their drawings and while they labeled them with identification labels such as “cat” or “tree”, they did not assign conceptual labels like “pollination” or “growth” (Moseley et al., 2010). Only two of the 118 drawings scored represented an understanding of how systems are dependent upon each other in the natural environment (Moseley et al., 2010).

The research team observed several drawings of homes, bedrooms, schools, classrooms and urban neighborhoods — scenes suggesting to Moseley et al., 2010 that the word environment did not bring forth images of nature in the minds of their participants. Citing the work of several other studies, Moseley et al. (2010) concluded that their sample population of pre-service teachers had an “object view” of the environment instead of a view in which humans interacted with the environment.

Before I continue, I need to point out that, prior to participants completing the DAET, Moseley et al. (2010) asked participants about their “residential experiences” (i.e., where they have lived for most of their lives). They found out that 21% of their sample population had lived in a rural environment, 32% in an urban environment, and 46% in a suburban environment. It should also be pointed out that prior to their participation in this study, the pre-service teachers had not received any training in environmental education (Moseley et al., 2010).

The results of the drawing section of the DAET are consistent with the results observed in the written section of the test, an evaluation that Moseley et al. (2010) described in a separate paper. The research team evaluated the drawing and written portions of the DAET separately so that the DAET-R could be evaluated for its validity as an assessment tool.

The results of their study prompted Moseley et al. (2010) to call for teacher education programs “that support pre-service teachers’ development of a conceptual model of the environment that integrates humans and the abiotic and biotic factors within the environment” as this would better prepare teachers to teach children about organisms, the environment, and biodiversity.

Read more about the research team’s recommendations and see how they used the DAET-R to evaluate drawings. Purchase a copy of this paper online or
search for this article at your local college library. A copy of the DAET and the DAET-R are included in this paper.


Literature Cited
Moseley, Christine, Blanche Desjean-Perrotta and Julianna Utley. 2010. The Draw-An-Environment Test Rubric (DAET-R): exploring pre-service teachers’ mental models of the environment. Environmental Education Research.
16(2): 189-208.


Also See

Read Full Post »

The Origins of Botany Education in the U.S.

Posted in botany, Teaching & Learning on September 14, 2012|

In the second part of his series about the history of botany education in America, professor Marshall D. Sundberg takes a look at how botany textbooks, classroom instruction and student learning evolved in the 19th century. Part Two in this series focuses on textbook authors, teachers and America’s first professional botanists.

Botany textbooks were big business in the 1800s as educators, botanists and botany enthusiasts strived to carry out two things: 1) Teach botany to the public, and 2) Turn botany into a professional discipline.

The author of the first bestselling botany book in the U.S. was the female “botanophile” (i.e., botany enthusiast), Almira Hart Lincoln Phelps (Sundberg, 2012). Phelps taught botany at a seminary and it is her experiences as a teacher that made her realize the need for a botany book for beginners. So she wrote a book based upon her lecture notes and published Familiar Lectures on Botany: Including practical and elementary botany with generic and specific descriptions of the most common native and foreign plants and a vocabulary of botanical terms for the use of higher schools and academies (1929). Phelps, who became the second woman elected to the American Association for the Advancement of Science in 1859 (Sundberg, 2012), had some competition in the textbook market. Competitors included her teacher Amos Eaton, Alphonso Wood (a popular author of taxonomy textbooks for all grade levels), and America’s first professional botanist, Asa Gray (Sundberg, 2012). Between them they published several textbooks for elementary schools, secondary schools and universities.

The growth of botany programs in the U.S. increased as the number of colleges and universities increased (Sundberg, 2012). Many firsts occurred during this period of growth. For example, in 1847 Asa Gray taught the first one-month intensive botany class that would become the precursor to upper division botany labs and graduate programs (Sundberg, 2012). In 1871, Gray taught the first summer workshops in botany for U.S. high school teachers (Sundberg, 2012). At Iowa Agricultural College professor Charles E. Bessey started the first botany lab for undergrads in America in 1873 and, one year later, introduced students at the University of California to laboratory methods in botany (Sundberg, 2012).

Today we take for granted the availability of journal articles about all aspects of teaching and learning in biology. There was a time, however, when they didn’t exist. This changed in 1880 when Bessey’s graduate student, J.C. Arthur, wrote the first teaching paper in a botanical journal (Sundberg, 2012). What was his article about? It was about how the stem of a pumpkin is a good laboratory example of a dicot stem (Sundberg, 2012). Two years later, Bessey wrote an article suggesting teachers use Asparagus stems as their laboratory example of a monocot stem (Sundberg, 2012).

As for teaching methods in botany, this was a new topic area too. William J. Beal described his approach to teaching botany in an article published in the Botanical Gazette a journal serving, as Sundberg (2012) describes it, as “the mouthpiece of the younger generation of botanists”. Beal’s pedagogical approach to teaching botany emphasized observation and the recording of written and visual descriptions (Sundberg, 2012).

And let’s not forget the first textbook about plant dissection. Written by J.C. Arthur, the Handbook of Plant Dissection was published in 1886 and in addition to all that you’d expect to find in a dissection manual, includes commentary about the value of drawing what one observes in lab.

Sundberg’s article about the development of botany education in this country sheds light on the origins of the different philosophies within the discipline, as well as different philosophies in biology education. Take for example, the 19th century conversation surrounding the value of biology education over botany and zoology education. Sundberg’s discussion of opposing philosophies brought back memories of grad school and the tensions within the biology department where I went to school. Back then there was much conversation about the development of a new curriculum that would change how botany and zoology classes would be taught. It was the “cell squishers” against the “lizard chasers” — this is how grad students saw it, anyway. One day a faculty member on the cell and molecular side used the word “archaic” to describe the department’s curriculum. Folks on the organismic side had their own opinions. It was interesting to read that riffs such as this one go back to the 1800s.

Sundberg’s series about the history of botany education is very interesting and I encourage you to read Part One and Part Two.

Some of the references Sundberg refers to throughout his article are available online. Below are links to two of the books. Enjoy!

    Gray, Asa. 1858.How Plants Grow: A simple introduction to to structural botany with a popular flora or a description and arrangement of common plants both wild and cultivated. New York: American Book Company.
    View online

    Henslow, Reverand Professor. 1858. Illustrations to be employed impractical lessons on botany. Adapted to beginners of all classes. Prepared for the South Kensignton Museum. London: Chapman and Hall. View online


Literature Cited
Sundberg, Marshall D. 2012. Botanical education in the United States: Part 2, The nineteenth century – Botany for the masses vs. the professionalization of botany. Plant Science Bulletin. 58(3): 101-131. Fall 2012. Web.
<http://issuu.com/botanicalsocietyofamerica/docs/psbseptember_-_58__3__2012> [accessed 13 September 2012]

Read Full Post »

« Newer Posts - Older Posts »