Like the monkey puzzle tree, the horsetails (Equisetum spp) are sometimes referred to as ‘living fossils’.  Some of their ‘relatives’ date back to the late Devonian period - about 380 million years ago.  Some were  huge and tree like, reaching a height of some 30 metres, about 98 feet.  These plants formed 'forests' and were abundant in the carboniferous period.  These ancient species persisted for some 100 million years, with some contributing to the formation of coal deposits.  Modern horsetails first appeared during the Jurassic period. Present day forms are much smaller than those of the past..  Equisetum arvense is a species that is widespread across Northern Europe and parts of America. It is a nonflowering plant, multiplying through spores. It can absorb silicon from the soil, which is unusual.  It also has the ability to take up and accumulate heavy metals such as copper, zinc, lead and cadmium.  It grows and spreads by underground rhizomes.  These rhizomes can form an extensive network, penetrating deep into the soil (sometimes to a depth of six feet).  This means the plant can be very difficult to eradicate if it appears in your garden. Techniques for removing the plant can be found on the RHS site : here.  Unchecked, Equisetum can spread extensively and smother / outcompete smaller plants. In Spring, the rhizomes produce pale, fertile shoots, topped with strobili.  Strobili are cone shaped structures that release spores. Once the spores have been released, these shoots wither and die.  Somewhat later, the non-reproductive shoots appear.  These have fine branches that appear in whorls around the ‘segmented’ stems. The whorls form at various ‘nodes’ along the stem.  These branches give the plant is characteristic form.  The name Equisetum comes from the latin Equus for horse, and setae for bristles, as the shoots have a vague resemblance to a horse’s tail.  The word arvense is also derived from the Latin where "arvum", means “ploughed”.  This references the growth of the plant in arable soil and disturbed areas.  Horsetails commonly occur in damp and open woodlands, and may also been found near the edges of streams (which may have been their original habitat). The plant has been used in herbal medicine to make a ‘tea’ or used in baths to treat skin complaints, chilblains and wounds.

Bees and light Honey bees need to sleep.  Unlike us, they do not sleep for long periods but they take ‘naps’ during the day and the night - within the hive where it is dark.   If the hive becomes over heated, then bees will move outside the hive and beat their wings to fan cooler air into the hive.  If the bees are exposed to artificial light during the night then there is evidence that their ability to perform the ‘waggle dance’ is impaired.   The dance is important as it tells other bees where to source pollen and nectar.   Cooling of the hive may become increasingly necessary with climate warming (and heat spells), which in turn might expose bees to artificial light at night.  Hives might need to placed away from road sides (hence car lights) and street lights.  An ancient pine. The Wollemi pine is rightly described as a living fossil.  It is a plant that has remained unchanged for millions of years.    An almost identical fossil form dates to the Cretaceous period , some 145 million to 66 million years ago.  Whilst the trees were abundant some 8 to 6 million years ago, now only 60 trees exist in the wild (in a canyon northwest of Sydney) and they are at risk of wild fires. The population of these pines has dwindled as the climate in Australia became drier and warmer.   The genetic make-up of the species has recently been analysed.  It turns out that the tree's 26 chromosomes contain some 12.2 billion base pairs; by comparison, the human genome has 3.4 billion base pairs.  The research also indicated there was very limited genetic diversity within the Wollemi pine population.  The existing trees appear to  have abandoned sexual reproduction, and now reproduce mainly by cloning, suckers emerge from the base of a tree and then grow on to become ‘new’ trees. Whether this remnant population of the Wollemi pine will survive ongoing climate change (and increasing risk of fire) remains to be seen.  The wollemi pine also appears to be susceptible to disease, in particular to Phytophthora cinnamomi, a pathogenic water mold that causes dieback.  

The monkey puzzle tree is a popular garden tree.  It is so-called as when first seen in this country (in the mid C19th) by Charles Austin, he is alleged to have said that “it would puzzle a monkey to climb that”.  As the tree had no common or popular name, it became the ‘monkey puzzler’ or ‘monkey puzzle tree’.  Its scientific name is Araucaria araucana, and otherwise known as the Chilean Pine or Pehuén.  It is native to the Andes of Chile and Argentina.  Not only is it a long lived tree (with a life span of a thousand plus years) but the species has been around for a long time (in excess of 200 million years).  It is sometimes described as a “living fossil”. A tree can grow to a considerable height - towards 150 feet with a trunk diameter of some five feet. Read more...

Just as the woodland blog has described the maidenhair tree as a ‘living fossil’, so the same phrase can be applied to the Dawn Redwood (Metasequoia glyptostroboides).  All species belonging the genus Metasequoia were thought to have died out sometime during the Miocene Period. The Miocene began 23 million years ago and ended about five million years back.  The Miocene saw the evolution of the first dogs and bears, the uplifting of the Alps and significant climatic changes such as the MMCO - the mid miocene climate optimum.  During the MMCO, the temperatures were above today’s average global temperature, which lead to drier conditions across the world with a consequent decrease in woodlands and an increase in a more open landscape.  The Metasequoias were casualties of this changing environment; the Metasequoia forests, which extended as far as 80oN,  disappeared.  Indeed, all species were thought to have gone but then in 1941, a living member of the genus was found in China - the water fir (as it was known locally).   Read more...

Ginkgo biloba or the maidenhair tree is unusual in many respects.  It is often described as ‘a living fossil” - as is the horseshoe crab and the coelacanth .   Ginkgo is a long lived, deciduous tree with distinctive leaves.  The leaves are fan shaped (jpg adjacent), but notched or divided - forming two lobes (hence biloba)  The leaf veins radiate out into the leaf blade from the leaf stalk - but do not form a network.  Two veins enter the leaf at its base and these split into two again and again.  This is known as dichotomous venation (see image).  The leaves can be between two and four inches long, and have a long, slender petiole (leaf stalk).   Apart from their physical appearance, the leaves of Ginkgo are unusual in term of the autumnal leaf drop.   Read more...

The maidenhair tree is otherwise known as Ginkgo biloba, or just Gingko is native to China, but is widely cultivated through the world.  The name Ginkgo may be derived from a misspelling of the Japanese Gin kyo or silver apricot - referring to the form of its fruit.   The biloba part of the name refers the two lobed form of the tree’s leaves. Ginkgo is a dioecious species, that is to say, there are separate male and female trees.   The female tree produces quite large seeds within a yellow brown soft fruit-like structure.  Though attractive in appearance, it has a a rancid smell.  The smell is due to butyric acid in the fleshy part of the fruit; and for this reason it is male trees that are usually cultivated.   The male trees produce small cone-like reproductive structures, not dis-similar to those seen on other gymnosperms. Read more...