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Results tagged “poaceae”

Aug 29, 2014: Themeda triandra

Taisha completes the series on South African plants and biomes with this entry. It is also her last official day as a work-learn student with Botany Photo of the Day, though there are about a half-dozen other entries she has written that will be posted while the new students learn the ropes. Thank you, Taisha. She writes:

Today we feature the grasslands biome of South Africa with photographs of Themeda triandra, which is known as rooigrass in Afrikaans ("red grass"). These images (image 1| image 2) were uploaded to the Botany Photo of the Day Flickr Pool by Marie Viljoen@Flickr. The first image was originally posted on Marie's blog, where she later posted a poem about Themeda triandra by South African poet, Antjie Krog. Thanks again, Marie!

The grasslands, also known locally as Grassveld, is the largest biome within South Africa. It is found mainly on the high central plateau of South Africa as well as the inland areas of the Eastern Cape. This biome neighbours the savanna, thicket, and Nama Karoo biomes. This region is relatively flat, though it can vary between sea level and 2850m elevation. The semi-arid to arid grasslands have varying temperatures, with frost being common. Precipitation ranges between 600-1000 mm, with rainfall decreasing westward. The grassland occurs on a variety of soils from humic clays to poorly structured sands.

A single vegetative layer of grasses dominates the grasslands, although other species such as bulbs occur. There are two categories of grassland: sweet veld and sour veld. Sweet grasses occur on the semi-arid regions of the Eastern Cape in eutrophic soils, while the sour grasses can be found in the higher rainfall regions of Drakensberg on acidic soils.

Themeda triandra is a tufted C4-photosynthesis perennial grass occurring widely across parts of Africa, Australia, and Asia. In South Africa, Themeda can occur in the savanna biome, but is primarily found in the grassland biome in regions with rainfall between 500-950 mm and at elevations of sea level-1800m. When young, this grass is a green to blue-green colour tinged pink. It then turns red with age. Rooigrass at higher altitudes tends to be shorter and darker compared to plants at lower elevations. The spikes flower from October to July. Flowers may or may not long black or white hairs. The awned spikelets hang from clusters and are surrounded by reddish brown leaf-like spathes or bracts. Rooigrass does not vegetatively spread long distances, so it is instead an obligate seeder. The long hygroscopic awns twirl when wet, driving the barbed seeds into the ground. There, they will germinate if there is a layer of litter or pioneer plants. This species is noted to be resistant to fire, with resistance increasing if the site is not overgrazed and burnt at regular intervals to allow for regeneration.

Apr 2, 2014: Zea mays (black-fruited selection)

Zea mays (black-fruited selection)

Taisha wrote today's entry. We were both challenged to find the bona fide botanical name for this taxon, and had to give up (no results in the USPTO database, for one), so we left it as a black-fruited selection (read more below). Taisha writes:

The past two days in Vancouver have been quite warm and enjoyably sunny--prompting many to get out into the garden. Some have begun planting seeds indoors or in greenhouses, and it won't be long until we can directly seed outdoors. Today, we have a photo of some caryopses of Zea mays. This black-fruited selection is a heritage strain of popping corn, popularized as a gourmet popcorn from Illinois (see notes associated with the original Flickr image for the name). Zea mays has been featured once before on BPotD, highlighting the work of Dr. Michael Blake from UBC's Department of Anthropology. Today's photo was uploaded to the Botany Photo of the Day Flickr Pool by Eric Hunt@Flickr. Thanks, Eric!

For those in the temperate northern hemisphere who are anticipating growing plants from seeds soon, I thought I would help explain some oft-used seed terminology. When flipping through seed catalogues or browsing online, you may come across seeds marketed as "certified organic", "heirloom/heritage", "open-pollinated", or "hybrid". What are the differences?

Certified organic (with an emphasis on Canada, as definitions and regulations are different depending on country): Organic seeds are seeds that are harvested from a plant grown in a way that meets organic regulations. According to Canada's organic production systems standards (there are provincial as well as international standards), methods are to be used to nurture ecosystems in order to be sustainably productive, increase biodiversity to provide weed and pest control, recycle plant and animal residues, select and rotate crops, manage water, and use tillage and cultivation techniques. A number of substances, methods, or ingredients are prohibited which include (but aren't limited to) products produced from genetic engineering, synthetic pesticides or other pesticides, containers containing synthetic fungicide, synthetic growth regulators, fertilizers, and sewage sludge (see: Canada's Organic Production Systems General Principles and Management Standards (PDF)).

Many seeds may be labeled organic, and since 2009 the official Canada Organic Logo has been voluntarily used to mark products that are organic. The certifying body must also appear on the label or at the point of sale.

Heirloom/heritage: Heirloom or heritage seeds are seeds collected from an open pollinated plant that has been cultivated for a number of years, which usually is around 50 years or more (it ranges from company to company). With heirloom/heritage seeds, each generation has been selected for specific characteristics and when grown, harvested, and propagated correctly the characteristics will be retained in each generation. Choosing heirloom varieties that have been grown in one region may be beneficial as they may have adapted to local conditions or may have tolerance to insects or disease that are known to be prevalent to the area.

Open-pollinated: Open-pollinated seeds are collected from plants that have been pollinated by insects, birds, wind, humans, or other natural mechanisms. Because the breeding is uncontrolled, plants may be more genetically diverse and exhibit differing traits. Over succeeding generations, the taxon may slowly adapt each year to local climate and growing conditions. Maintaining a strain may be difficult, as you must avoid the introduction of pollen from other varieties. Some choose to grow heirloom varieties in isolation either by creating barriers, enclosures, or planting in greenhouses.

Hybrid: Hybrid seeds are products of elite plants with specific traits that are cross-pollinated. The generation grown from the seeds of this cross (the F1 Hybrid) is likely to exhibit improved growth and yield through heterosis or hybrid vigour. A warning though--if you were to collect and grow the seed from the F1 hybrids, you would have an F2 generation that lacks the consistency of the desired traits seen in the previous generation.

With this information, I hope you will be able to make the best choice of seed for planting in your own garden. For local gardeners, suggested planting times for Vancouver can be found in local or regional publications (such as almanacs) or from local seed companies such as West Coast Seeds (PDF of planting chart).

Nov 14, 2012: Phyllostachys elegans

Phyllostachys elegans

There were many highlights to our botanical trip to the southeast USA earlier this year, including a visit to the Coastal Georgia Botanical Gardens at the Historic Bamboo Farm in Savannah, Georgia. The institution does indeed have a lot of history (from their web site): "[The Barbour Lathrop Bamboo Collection] is the result of the USDA's effort to introduce to the public, particularly southern farmers, the many uses of bamboo. The collection began in 1902, when Barbour Lathrop asked Dr. David Fairchild to obtain plants for him in Japan. Organized collecting began in earnest in 1906 by Frank Meyer, a USDA plant explorer, and continued with Dr. F.A. McClure until 1945. With over 150 species, this is the largest collection of bamboo available for public viewing in the United States."

Phyllostachys elegans, or elegant bamboo, was scientifically named and described by the same Dr. McClure in the Journal of the Arnold Arboretum in 1956. Names and descriptions of plants have to be based on a physical object, i.e., a specimen of some kind (typically a dried plant specimen, but historically an illustration would also have sufficed). This specimen that is used to define the species is designated the type specimen. Reading Dr. McClure's account (New Species in the Bamboo Genus Phyllostachys and Some Nomenclatural Notes), I noted the type specimen for Phyllostachys elegans was from a plant in the Barbour Lathrop Bamboo Collection, having the identification number 128778--the same as the plant in today's photograph. In other words, the species Phyllostachys elegans was named and described from this exact plant. From the label: "Phyllostachys elegans. Elegant bamboo. Plant #128778. Max ht. 32ft. Max. dia. 2.25". Min. Temp. 0F. Collected 1936 by F. A. McClure, Hainan Island. Received 1938, USDA, Savannah, Georgia. Origin: China. Prized as ornamental and for shoots."

Additional descriptions of this species are available via the Flora of China: Phyllostachys elegans and RBG Kew: Phyllostachys elegans.

Aug 28, 2012: Fargesia sp.

Fargesia sp.

Today's write-up is courtesy once again of BPotD work-study student Bryant DeRoy. He writes:

This exceptional image by Eckhard Volcker (aka Tatcher a Hainu@Flickr) is a cross-section of a Fargesia species, or a clumping bamboo (Poaceae). Eckhard, your submission via the Botany Photo of the Day flickr page is much appreciated! To see more of Eckhard's work, also visit his web site: Wunderkanone.

The process of taking such images through a light microscope is known as photomicrography. This thin section of bamboo stem was treated with a number of stains and then viewed through a light microscope with a polarized light filter. The use of stains helps to highlight the cellular structures of this bamboo cross-section. The structures outlined in fuchsia are the vascular bundles. The fuchsia stain is concentrated in the vascular fibres that surround the vascular bundles and also form a ring just inside the epidermis.

Densely packed longitudinal cellulose fibres (held together by lignin) that make up roughly 40% of the stem or culm (60-70% by weight) are the main contributing factor to the general strength and durability of bamboo. The structure of these fibres allows some species of bamboo to reach considerable heights, especially for a grass! For more information on the cellular structure of monocotyledons, visit Wayne Armstrong's Stem and Root Anatomy teaching page.

The cellular structure of the bamboo culm is also responsible for its use in a wide variety of applications. Bamboo is gaining popularity as a sustainable crop because of its high rate of growth and high crop density. Another major attribute is that the relative strength of bamboo remains fairly even over its lifetime and does not tend to correlate with age, whereas most wood gets stronger as it grows older (in other words, it can be harvested earlier). Read The Structure of Bamboo in Relation to its Properties and Utilization (PDF) for more on these topics!

The cultivation of some bamboos, however, have also led to problems with invasiveness in some instances. Many species of bamboo grow from horizontally-spreading and self-propagating rhizomes, which aid in their ability to take over areas and shade out other species (being clumping species, though, Fargesia species are generally considered "well-behaved" and not invasive). As some of you may know, some bamboos can be difficult to remove once established as they can regenerate from their underground rhizomes, even if the above ground shoots have been removed.

Aug 1, 2012: Kettle Mountain Meadows

I thought I'd add a visual coda to the series on colours in plants, since Bryant is feeling under the weather today. These photographs are from last weekend's near-solitary field-trip up to the peak of Kettle Mountain while I was attending Botany BC. As of a few weeks ago, these meadows formed part of the northeast edge of the Cascade Recreation Area, but they have now been added to E.C. Manning Provincial Park. One hopes that this might mean additional enforcement in dealing with those who despoil the meadows by driving off-trail (examples of both responsible and irresponsible use if one searches Youtube for "Whipsaw" and "Trail").

Jan 10, 2012: Elymus canadensis

Elymus canadensis

A short entry today, I'm afraid--I'll post a longer entry of this species sometime showing the entire plant with a mammal counterpart.

The range of Canada wild rye stretches from west to east in North America, and reaches its northern extent in the Northwest Territories. At its southern limit, it inhabits three northern Mexican states: Chihuahua, Coahuila, and Nuevo Leon. It is found in almost every state and province in between, with the exception of some states in the southeast USA and the easternmost provinces in Canada.

Dec 20, 2011: Saccharum officinarum hybrids

Today's photographs are courtesy of two contributors. Eric Hunt, aka Eric in SF@Flickr shared the first image, and he has a number of additional images here: Saccharum officinarum). 3Point141@Flickr contributed the second image. Thanks to both of you for helping with the Botany and Spirits series!

Saccharum officinarum is a cultigen, a taxon of cultivated origin. Other examples of cultigens previously featured on BPotD include rice and cassava. One of the commercial sugar canes, Saccharum officinarum was hybridized over millenia, with origins in (likely) New Guinea. Many cultivars exist and continue to be bred, in order to improve properties such as disease resistance and sugar production.

Additional reading on the history and use of sugar cane (or noble cane) is available via the Ethnobotanical Leaflets of Southern Illinois University: "Sugar Cane: Past and Present" or James A. Duke's Handbook of Energy Crops: Saccharum officinarum.

In addition to being the largest source for sugar production, sugar cane is used in the production of the distilled alcoholic beverages rum and cachaça. Unlike yesterday's Juniperus communis, where the contribution to gin was flavouring, rum and cachaça are derived from fermented and distilled sugar cane liquids. Cachaça, the most popular spirit in Brazil (1.5 billion litres annual consumption), is made from fresh sugarcane juice that is fermented and distilled. Rum is a bit more complex, in that it can either be derived in a similar manner to cachaça or, more typically, produced from molasses (a byproduct of sugar production from the canes).

Given that sugar cane has been cultivated for millenia, it is likely no surprise that fermented drinks from sugar cane also date back to antiquity. However, distillation of the fermented liquids to produce the true rums only occurred in the 17th century, on sugarcane plantations in the Caribbean. Wikipedia again has an excellent entry (it seems like Wikipedia writers like alcohol) on rum, including suggestions on the origin of the name as well as a history of rum (did you know that Rhode Island rum was considered an accepted currency in Europe for a short period of time?).

Dec 12, 2011: Whipsaw Creek Road

Whipsaw Creek Road

Just the photograph today -- exams for Katherine combined with a number of deadlines and meetings for me equals few entries, unfortunately.

Claire has organized this week's Botany Photo of the Day series as part of the University of British Columbia's Celebrate Research Week. Claire introduces today's UBC researcher:

Dr. Michael Blake is in the Department of Anthropology and Laboratory of Archaeology at UBC and studies the ancient distribution and movement of Zea mays in the Americas.

Dr. Michael Blake writes:

Maize (Zea mays subsp. mays L.), or corn as it is more commonly known in North America, has a remarkable history. This domesticated tropical grass, that today forms one of the world's most important staple crops, descended from the wild grass, teosinte (Zea mays subsp. parviglumis H.H. Iltis & Doebley), which grows naturally in west central Mexico. (Daniel adds: the photograph above is a comparison of Zea mays subsp. parviglumis and maize, photographed by Hugh Iltis, and courtesy of the Doebley lab at the University of Wisconsin). In the past ten years, plant geneticists have made several important discoveries about the history of Zea mays based on the genetic similarities and differences among all the modern varieties that people grow throughout the Americas. One of these discoveries is that Zea mays was most likely domesticated in only one region of Mexico--by indigenous peoples who lived in the Rio Balsas region--and from only one subspecies of teosinte and its close relatives. What is so interesting, and puzzling, about the earliest human use of teosinte, perhaps some 9,000 years ago, is that the seeds of the plant are very tiny, don't grow in cobs, and are surrounded by an exceedingly tough glume (bract). Why were early farmers interested in this plant? Archaeologists, beginning in the 1950s, have excavated many dry cave sites in Mexico but have yet to find the smoking gun indicating the earliest use of teosinte for food. In fact, despite more than a century of archaeological investigations in Mexico, we have yet to find any convincing evidence that people actually ate teosinte (or used it for any purpose for that matter).

In the late 1930s, George Beadle, a Nobel Prize-winning geneticist and former president of the University of Chicago, argued that teosinte must be the wild ancestor of Zea mays and, furthermore, that it likely underwent just a few genetic mutations (as few as five or six) that transformed it into early corn. The earliest Zea mays fragments we know of come from a cave in the state of Oaxaca in southern Mexico--not too far south of the present-day range of Zea mays subsp. parviglumis. These two fragments date to about 6200 years ago and show that one of the genetic changes was the development of the cob, along with the softening and retracting of the hard glumes. This made corn much more desirable to ancient Americans because not only were the nutritious kernels now easier to access, but they were all together on a four-rowed rachis, or cob, that didn't break apart when it ripened. This, and a handful of other genetic transformations set Zea mays and humans on a path of mutual dependence that has only increased over the succeeding millennia.

The map shows the earliest archaeological sites in each region of Mesoamerica (Mexico and Central America) and North America which have directly-dated maize remains (from Ancient Maize Map). It is the result of my research team's efforts to gather together all the known examples of maize that have been recovered and that have been dated using radiocarbon dating (14C).

When we compiled all of the dated fragments on our on-line database Ancient Maize Map, it was possible to see clear patterns of dispersal, much as we might expect if modern day corn descended from Zea mays subsp. parviglumis (teosinte) in west-central Mexico and was spread outwards from there. Perhaps most intriguing discovery is of many sites in Arizona and New Mexico, where corn was being grown by at least 4,000 years ago. The material collected is most often a cob or cob fragment, but some material includes kernels, leaves, stalks, even roots and preserved coprolites--much of it found in caves. Other small particles we collect of Zea mays preserve in the form of phytoliths, starch granules, and pollen. While these microscopic particles can't yet be dated themselves, some get trapped in datable residues left behind on pottery, milling stones, and even in dental callus. Where the residues have been directly dated, they show very early evidence of maize having reached Ecuador in South America by about 5,000 years ago. This suggests that Zea mays must have been of great interest to the earliest farmers from South America to North America and all points in between. It is the small particles of maize starch found on pottery fragments that have revealed an unexpectedly early movement of maize northwards across the Great Plains and into the south Prairies of Alberta and Manitoba. The map shows maize made its way into the economies of people in southern Alberta by between about 750 to 950 years ago. Charred maize kernels have been just north of Winnipeg dating to 550 years ago. Likewise, Zea mays has been found as far south as Chile and Argentina by about 2000 years ago.

Explore the UBC archaeological maize database and interactive mapping program at Ancient Maize Map. Make your own maps showing the distribution of maize in the Americas and zoom right into the regions and sites where the earliest remains of maize have been found. As more discoveries are made and as new radiocarbon dates come in, we will continue to update the database and track the history of maize--one of the world's most economically important crops.


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