Max Coleman

Aug 302016
 
Ian Edwards (RBGE) joins Meg on the first leg of the walk.
Male wool carder bee on a favoured leaf from which he defends his territory.

Male wool carder bee on a favoured leaf from which he defends his territory.

This morning around 11am Meg Beresford set off on her ‘Let’s Make a Bee Line’ walk from the Royal Botanic Garden Edinburgh to Wiston Lodge covering 10km a day over 8 days.

The 10km a day is a carefully chosen number. It is all bound up with the bees Meg is bringing to our attention. A foraging bumblebee will fly 10km from its nest in search of pollen and nectar. Unfortunately, modern farming, and other changes in the environment, are making conditions for bees increasingly challenging. Meg wants to bring the plight of bees to a wider audience and fund raise for a meeting on bee conservation to be held at Wiston Lodge.

You can follow Meg’s progress at The Buzz Feed, a blog that will chart the progress of the walk. This will also give information of events that will happen along the way. If you would like to support Let’s Make a Bee Line donations can be given at https://makeabeeline.org/honey/

Meg at the Water of Leith on the first day of her Let's Make a Bee Line walk to raise awareness about the plight of bees.

Meg at the Water of Leith on the first day of her Let’s Make a Bee Line walk to raise awareness about the plight of bees.

Ian Edwards (RBGE) joins Meg on the first leg of the walk.

Ian Edwards (RBGE) joins Meg on the first leg of the walk.

Aug 302016
 
Mottled Beauty.

Moth trapping in the Garden is now happening on a regular basis with the input of Edinburgh Natural History Society and MSc student Tom Dawes.

Records from 29th/30th August:

Ypsolopha dentella (Honeysuckle moth) – 2; Blastobasis adustella – 9+; Large Yellow Underwing – 57; Lesser Broad-bordered Yellow Underwing – 1; Broad-bordered Yellow Underwing – 1; Copper Underwing – 3; Mouse Moth – 1; Mottled Beauty – 2; Flounced Rustic – 1; Dun-bar – 1; Acleris sp. – 1; White-line Dart – 1; ?Brown House Moth – 1; probable Ingrailed Clay – 1; Agriphila tristella – 1; Dark Arches – 1.

Copper Underwing.

Copper Underwing.

Mottled Beauty.

Mottled Beauty.

Marbled Beauty.

Marbled Beauty.

Records from 10th/11th August:

Mottled Beauty – 1; Large Yellow Underwing – 43; Fan-foot – 1; Lesser Yellow Underwing – 3; Large Broad-boardered Yellow Underwing – 1; Golden Dart – 1; Dotted Clay – 1; Small Fan-foot Wave? – 1.

Jul 272016
 
Pond dipping at Benmore BioBlitz.

Pond dipping at Benmore BioBlitz.

Counting the wild species in a given area in a set time is the aim of a BioBlitz. Clearly, the biggest list will be produced by involving as many people as possible who can identify a wide range of organisms. It was with the aim of being a record breaker that the Benmore BioBlitz kicked off at 4 pm on Friday 15 July with a team of over 20 expert recorders. The Benmore Botanic Garden event was the fourth in a series of Bioblitz events and  by 4 pm on Sunday 17 July 288 species were recorded. However, this was not the final figure as many specimens were collected that needed microscopic examination to determine their identity. There was also a backlog of paper records to be added at the end of the event.

Gold spangle moth.

Gold spangle moth.

So, what did we discover about wildlife at Benmore Botanic Garden? Well, for a start, the record for longest list was well and truely broken. The previous event totals were: Edinburgh 556 species; Logan 360 species and Dawyck 561 species. I was quietly confident that with a team that included expertise in lichens, bryophytes and fungi (all diverse groups at Benmore) we had a good chance of a record species list. The weather was not kind and rain kept flying insect numbers down, so it was a very pleasant surprise to find that all the hard work during and after the BioBlitz had resulted in a record breaking list of 707 species. The largest single group was higher plants with 185 species, but bryophytes (mosses and their allies) came a close second with 172 species. Fungi came third with 122 species, and moths fourth with 68.

The moth count was a fantastic achievement considering the weather conditions! Seven traps were set out on both nights.

Purple bar.

Purple bar.

Tom and Andrew identifying moths.

Tom and Andrew identifying moths.

Top left Tunbridge filmy fern, a rare species located during the BioBlitz.

Top left Tunbridge filmy fern, a rare species located during the BioBlitz.

The details are still being digested, but some notable species are already emerging. The rare Tunbridge filmy fern (Hymenophyllum tunbrigense) was located near the Golden Gates. This tiny fern with a frond that is only a single cell thick is restricted to humid sites and is a speciality of the Celtic rainforest that survives in the area around Benmore Botanic Garden in fragments of native coastal woodland. Sticking with ferns some natural regeneration of a tree fern in the genus Dicksonia was noted. In contrast to the filmy fern this group of ferns includes some giants that can reach several metres. Presumably these plants are the result of spores that have escaped from the Benmore Fernery. Only time will tell what species they are and whether they can withstand the Benmore climate, but they are unlikely to ever match the impressive outdoor specimens at Logan Botanic Garden. The final tally for ferns and their allies was 23 species.

Among the oddities the prize has to go to the flowers of tan. This curious bright yellow mass is a slime mould (Fuligo septica). The name comes from its frequent appearance in tan bark bits used in tanning hides. For a long time these strange organisms were grouped in with the fungi, but are today regarded as a separate group called slime moulds. Also known as dog vomit slime mould and scrambled egg slime, for obvious reasons, this truely odd organism is nonetheless very easy to spot. Keep an eye out for it next time you are in the woods!

Dog vomit slime mould.

Dog vomit slime mould.

Special thanks must go to all the recorders, without whom the record breaking list could not have been created. The Lorn Natural History Group provided a number of expert recorders and in due course will process all of the records so that they become publicly available via the website of the National Biodiversity Network.

The final list breaks into groups as follows:

3 Mammals; 32 Birds; 3 Amphibians; 1 Butterfly; 68 Moths; 7 Hoverflies; 7 Flies; 5 Beetles; 6 Bugs; 7 Bees, wasps and ants; 4 Other insects; 1 Spider; 2 Slugs and snails; 5 Crustaceans; 1 Centipede; 2 Millipedes; 1 Other animal; 185 Plants (excluding ferns and mosses); 23 Ferns and allies; 172 Mosses and allies; 122 Fungi and 50 Lichens.

Jul 262016
 
Male wool carder bee on a favoured leaf from which he defends his territory.

Male wool carder bee on a favoured leaf from which he defends his territory.

The wool carder bee (Anthidium manicatum) is one of the most distinctive solitary bees that lives in the Garden. During July and August the Demonstration Garden and the Rock Garden are good places to look for these lively territorial solitary bees. Your best chance of seeing a wool carder bee will involve first locating the woolly plant that the bee has a special relationship with – lamb’s-ear (Stachys byzantina). Female wool carder bees hunt out this plant and others, such as Stachys alpina, in order to harvest hairs for the construction of their nests. Four beds of Stachys have been specially planted to encourage wool carder bees within the Fruit Garden. Weather also plays a part as the bees are more active on warm sunny days.

Stem of lamb's-ear showing bald patches due to the wool collecting activity of female wool carder bees.

Stem of lamb’s-ear showing bald patches due to the wool collecting activity of female wool carder bees.

This bee is worth looking out for as it is relatively new to Edinburgh, with the first sighting in the City made on 22 July 2011 at the Botanics. All previous records of this species in Scotland are from Dumfries and Galloway, and quite how it reached Edinburgh is unknown. However, it is clearly at home here as subsequent sightings have shown it to be established in Blackhall, Broughton, Leith and Craigentinny. This year it was spotted for the first time in the gardens of Holyrood Palace.

The bee itself is not obviously marked, although yellow dots on either side of the abdomen are worth looking for. What is most striking is some curious behaviour. The males can establish a small territory that they patrol, often returning to a favoured spot to rest. Intruders that are not female wool carder bees are attacked and chased out of this territory. During patrols the males can hover motionless in the air just like a hoverfly. This hovering is one of the best ways to spot wool carder bees for the first time. The females are smaller and generally go about their business of harvesting small balls of hairs and stocking their nests with pollen and nectar to feed their young. A short video of a female bee collecting hairs from Stachys can be seen here.

A ball of 'wool' dropped by a female wool carder bee.

A ball of ‘wool’ dropped by a female wool carder bee.

Curiously, not all males establish a territory. Smaller males that might be mistaken for the obviously smaller female bees seem to persist by adopting a sneaky mating strategy that involves none of the effort of defending a territory.

Male wool carder bee viewed from above showing the distinctive pattern of yellow dots on the abdomen.

Male wool carder bee viewed from above showing the distinctive pattern of yellow dots on the abdomen.

Apr 062016
 
Flower of Myrmephytum arfakianum.

Some of us try our best to discourage ants in the garden. I’m not sure why as they really don’t do any harm. However, in the plant kingdom there are a few species that actively encourage ants to live within them in specially created ant homes that are grown by the plant. On the face of it this seems like the oddest thing for a plant to do. On closer examination it becomes clear why a plant would go to the bother of cultivating an ant colony. The most important bonus is a 24/7 security service. Any other animal that might cause harm to the ant plant is instantly attacked by an army of minature defenders with fearsome jaws. Another benefit is that the ant waste contains lots of valuable plant nutrients that are absorbed by special structures inside the home created for the ants.

Flower of Myrmephytum arfakianum.

Flower of Myrmephytum arfakianum.

Right on cue an ant plant from the Arfak Mountains in West Papua, Indonesia, is now flowering as part of a display for Edinburgh International Science Festival. We have enhanced our children’s glasshouse trail – Survival of the Smartest – with a display of plants showing a range of survival adaptations, and among them is Myrmephytum arfakianum with its very odd looking blue flower. To be honest the entire plant is the strangest looking thing. If you image a prickly haggis you just about have it. You can see this botanical curiosity in the Temperate Palm House until Sunday 10th April after which it will be taken off public display.

The ant plant is just one of many plants featuring in the Survival of the Smartest trail for Science Festival. Young explorer’s can discover how plants could help them survive in an emergency and how the plants are able to survive in all sorts of different conditions through smart adaptations. Making homes for ants is really just the begining… Continue reading »

Mar 242016
 
MSc student Tom Dawes with one of the moths from the Garden's new moth traps.
MSc student Tom Dawes with one of the moths from the Garden's new moth traps.

MSc student Tom Dawes with one of the moths from the Garden’s new moth traps.

Monitoring the wildlife in the Garden is an ongoing task that helps us understand the value of gardens, and other amenity greenspaces, for all sorts of different animals. Moth trapping is the latest activity to become a regular focus of attention. With the help of a grant from the Friends two portable moth traps have been purchased to allow regular trapping throughout the year.

Recent BioBlitz events at the Edinburgh Garden, Logan and Dawyck have all shown how many moth species are using the gardens as a habitat. A typical summer trapping could easily include 60 different species. Some are impressive large species you might think would only be encountered somewhere more exotic than Edinburgh.

Around 6pm on the 23rd March a single mains-powered Skinneer trap was set in the Garden and left running over night. The following morning moth recorder and Garden MSc student Tom Dawes found eight individuals of four different moth species. Two of these, Twin-spotted Quaker and Chestnut, (pictured below) are new records for the Garden.

Tom has been trapping moths since his grandfather bought him a trap as a 12th birthday present. According to Tom…

Now is a good time to check for species that are more cold tolerant and would normally be emerging in early spring. Trapping all year will build up a much better picture of the moths of the Garden and is well worth doing despite numbers often being low in winter.

IMG_2115The future of moth trapping looks bright. Both the Edinburgh Natural History Society and local volunteer recorders helping Butterfly Conservation have offered to help ensure regular trapping takes place.

Work is in the final stages to produce a new moth atlas for Britain and volunteer recorders are keen to get records for areas that are currently relatively poorly recorded. All of the Garden’s moth records will be made available for this national effort and will be sent to the local biological records centre.

Ultimately all of this data is freely available via the online resource called the NBN Gateway. So if you want to know more about the wildlife in your area the information is only a mouse click away.

Common Quaker.

Common Quaker.

Twin-spotted Quaker.

Twin-spotted Quaker. A new record for the Garden.

Hebrew Character.

Hebrew Character.

Identity yet to be determined.

Chestnut. A new record for the Garden.

Mar 182016
 
The completed display.
Examining Sapotaceae fruits and seeds in the Herbarium with Sapotaceae researcher Peter Wilkie.

Examining Sapotaceae fruits and seeds in the Herbarium with Sapotaceae researcher Peter Wilkie.

If anyone had asked me if I knew any plants belonging to the Sapotaceae family eight weeks ago, I would have had no suggestions – I probably wouldn’t have even been able to spell the word Sapotaceae! With around 1300 species, the tropical tree family Sapotaceae is incredibly diverse. From latex production to edible fruits (and just about everything in between!), the plants within this family are of great economic and environmental importance.

Miracle berry fruit makes sour food taste sweet.

Miracle berry fruit makes sour food taste sweet.

Perhaps my favourite discovery from researching this plant family is the miracle berry (Synsepalum dulcificum). The ‘miraculous’ element of this plant comes from its ability to change how we perceive tastes – after eating this berry, all sour foods taste sweet! We managed to source tablets containing miracle berry extract and decided to test their effect by eating a slice of lemon after eating the tablet. I was a little sceptical and wondered whether I would only notice a change in taste because I knew there was supposed to be one. However, I discovered that the change in taste was not at all subtle – the lemons tasted like sweet oranges! As someone with a sweet-tooth, this calorie-free phenomenon is very exciting! The potential applications of the miracle berry as a natural and healthier alternative to sugar could be revolutionary to dieters and diabetes patients alike.

Seeds of Sapotaceae from the research collection in the Herbarium. Sapotaceae have a characteristic dull scar with the rest of the seed surface often being glossy. Here the middle seed shows the scar uppermost.

Seeds of Sapotaceae from the research collection in the Herbarium. Sapotaceae have a characteristic dull scar with the rest of the seed surface often being glossy. Here the middle seed shows the scar uppermost.

Little did I know when I began this placement I have actually been using products derived from members of this family every single day! Shea butter, found in many cosmetic products, is a product from Vitellaria paradoxa, another species within the Sapotacae family. I discovered that shea butter is not only great for treating skin conditions, but for anti-inflammatory medical uses, and has great potential as a biodiesel. This great number of diverse applications was a common feature of many of the plants I researched. To coincide with the Garden’s spring exhibition about the Sapotaceae – Nature Mother of Invention – I have been involved in developing a display about the Sapotaceae. This covers floral and fruit diversity in the family as well as four examples of animals that have specific interactions with Sapotaceae trees. The animal interactions have been written up as a separate blog The dodo tree and other stories.

The practical, technical and revolutionary applications of the Sapotaceae family throughout history are largely due to the special properties of the latex produced by species of Palaquium, otherwise known as gutta-percha. This was the wonder substance of Victorian Britain and was used in the same way that we use plastics today for moulding. The most revolutionary development to arise from the Sapotaceae family is arguably the linking of the world with high-speed communication via telegraph cables laid on the ocean floor. These cables were only possible with gutta-percha insulation around the copper core.

Installing the Sapotaceae display in the John Hope Gateway Building.

Installing the Sapotaceae display in the John Hope Gateway Building.

The display I have worked on has been able to draw upon the research on Sapotaceae diversity that is a focus for the Royal Botanic Gardens Edinburgh. This work is documenting species unknown to science. Without a name nothing can be communicated about a species potential uses or their place in the wider ecology of the habitats where they grow. Given the great utility of this plant family so far it is natural to wonder what exciting new discoveries may be just around the corner. The Sapotaceae truely is the most interesting plant family you’ve probably never heard of.

The completed display.

The completed display.

This post is by guest blogger Sarah Fleming, Science Communication MSc student at the University of Edinburgh.

 

 

Mar 172016
 

The Sapotaceae plant family provides us with some wonderful examples of the sometimes intricate interactions plants have with animals. One of the more intriguing cases is that of the so called dodo tree, or tambalacoque. Like many members of the Sapotaceae family the tambalacoque tree, known to botanists as Sideroxylon grandiflorum, is a tropical species. It is found only on the island of Mauritius, home of the now extinct flightless dodo bird.

Early engraving of a dodo, the famous extinct flightless bird from Mauritius.

Early engraving of a dodo, the famous extinct flightless bird from Mauritius.

In the 1970s there was concern that the tambalacoque tree was on the brink of extinction. There were supposedly only 13 specimens left, all estimated to be about 300 years old. The true age could not be determined because, like most tropical trees, tambalacoque has no growth rings. Scientist Stanley Temple came up with the theory that the tree relied upon the dodo to complete its life cycle. Temple thought that before the tough seeds would germinate they must first pass through the digestive system of the dodo. The idea was that the abrasion in the bird’s gizzard and the stomach acids would start to breakdown the seeds surface, allowing water to penetrate and triggering germination.

The extinction of the dodo in the 17th century, due to hunting by people, was linked by Temple to the absence of young trees. Put simply, the extinction of the dodo was preventing the tambalacoque from regenerating and the tree seemed doomed to go the same way.

This was a compelling and plausible story, and not surprisingly captured people’s attention. However, the story has a more positive postscript. Further research has shown that surviving tortoises are also likely to disperse the seeds of this tree, and more tambalacoque trees have been found, including some younger individuals. Although now discredited as the sole agent of dispersal, the dodo’s relationship with this tree still continues to fascinate.

Animal interactions with other members of the Sapotaceae family include some equally fascinating stories. A relative of the tambalacoque in the same genus, Sideroxylon inerme, the white milkwood tree, attracts a wide variety of animals to feed on its flowers and fruits. This southern African coastal tree has fruits, similar to blackberries, that are delicacies for bats, monkeys and bush pigs. While the small, greenish and rather malodorous flowers, are a favourite food of the speckled mousebird with its distinctive brown head crest.

Speckled mousebirds eat the flowers of white milkwood trees, Sideroxylon inerme.

Speckled mousebirds eat the flowers of white milkwood trees, Sideroxylon inerme.

Whole fruit of Omphalocarpum from the research collection in the Herbarium.

Whole fruit of Omphalocarpum from the research collection in the Herbarium. The image behind shows the trunk of a tree studded with fruit.

In Africa’s tropical forests Omphalocarpum elatum produces fruits that can be as much as two kilos in weight. These large fruits are sought after by the forest elephants, and it is only the elephants that can break through the hard shell. When the fruit falls to the ground the sound echoes through the depths of the forest and attracts elephants. They always follow a specific path, specially carved out of the forest to the Omphalocarpum tree. After positioning the fruit with their trunk, the elephants skewer it with a tusk and split it open. This interaction is ecologically important, as seeds pass through the elephant’s digestive system and germinate more easily. The close connection between Omphalocarpum trees and elephants echoes the dodo tree story. However, here the tree does seem to rely on just one animal to disperse its seeds. Declines in forest elephant populations really could put pressure on Omphalocarpum trees, and this is a good example of the often unexpected interconnections in nature. This particular interaction has only recently been discovered and a short video clip of elephants feeding on Omphalocarpum fruit can be seen here.

Antheraea paphia, one of the moth species that is the source of wild silk.

Antheraea paphia, one of the moth species that is the source of wild silk.

Travelling from Africa to India, there is another species of tree in the Sapotaceae family of high economic and ecological interest. The tree in question is Madhuca longifolia, and it is vital for the life cycle of the moth – Antheraea paphia. The larvae of this moth are silkworms and they eat the leaves of the tree before building their cocoons. It is these cocoons that are collected from the wild and processed to produce the sought after wild silk, also called tussar silk. This type of silk is commercially important in India and is appreciated for its special qualities.

As well as their stories these trees show us a fundamental aspect of nature. Interactions between animals and plants are everywhere. They are both complex and dynamic, but fragile at the same time. If we ignore these connections between plants and animals more species will face the same fate as the dodo.

This post is by guest blogger Theodora Mouschounti, an MSc student studying Science Communication and Public Engagement at The University of Edinburgh. It was researched during preparations for a major new exhibition about the Sapotaceae plant family – Nature Mother of Invention – at the Royal Botanic Garden Edinburgh.

Dec 162015
 
Brassica plots at Glasgow Botanic Gardens in summer 2015.
Wild celery seedlings in the poly tunnel at the Botanics in spring 2015.

Wild celery seedlings in the poly tunnel at the Botanics in spring 2015.

As 2015 draws to a close we end the third growing season for the Really Wild Veg project. The aim of the project is to explore how domestication has changed crop plants by comparing them with their wild ancestors in growing trials. As in previous years trials have been conducted here at the Botanics, by the Edible Gardening Project team, and at Redhall Walled Garden and Hermitage Vegetable Garden. A newcomer for 2015 has been Glasgow Botanic Gardens. Elizabeth Mittell, a PhD student with the University of Glasgow, is studying brassicas in order to explore the potential of this important group of crops in the context of increasing food demands and the stresses imposed by climate change.

Some of the growth trials at Glasgow Botanic Gardens have fed directly into the nutritional work being carried out by the Rowett Institute of Nutrition and Health as part of the Really Wild Veg project (see below). For more on Elizabeth’s work on brassicas check out her blog.

Brassica plots at Glasgow Botanic Gardens in summer 2015.

Brassica plots at Glasgow Botanic Gardens in summer 2015.

A particularly fun part of the project this year has been to explore taste preferences with members of the public in blind tastings. In general wild relatives of crops have stronger flavours. What we wanted to know was how people regard these flavours. Tastings at public events seemed an ideal opportunity to both engage a wider audience with the aims of the project and at the same time generate an indication of flavour preferences. To this end a series of blind tastings were conducted and the results are outlined below as the percentage vote for the best flavour:

Crop Circle discussion (panel of 47): Wild Cabbage 55% (26) vs. Cabbage 45% (21)

Crop Circle discussion (panel of 47): Wild Celery 70% (33) vs. Celery 30% (14)

SciMart market (panel of 71): Wild Cabbage 46% (33) vs. Cabbage 54% (38)

SciMart market (panel of 70): Wild Celery 51% (36) vs. Celery 49% (34)

Royal Highland Show (panel of 14): Wild Cabbage 79% (11) vs. Cabbage 7% (1) with 14% (2) undecided

So, in four out of five tests the wild plant gained a majority of votes, although in three of these cases the preference for wild over domesticated was not particularly marked. Despite not being scientifically robust data, these results do hint at a liking for more intense flavours.

Interestingly, a visiting group of students from Queen Margaret University studying for an MSc in Gastronomy also participated in a taste test with wild cabbage and cabbage. One might expect that such a group of highly-tuned palettes would be able to detect differences between the samples. The results below show a clear preference for the wild plant:

QMU student visit (panel of 15): Wild Cabbage 73% (11) vs. Cabbage 27% (4)

Celery trial plots at the Botanics showing wild celery (left), which is clearly less leafy and erect.

The format of the growing trials has remained the same in 2015. Three replicates of each species are grown side by side in blocks to try to ensure that environmental variation is kept to a minimum. The replicates represent different strains as follows: 1. wild type (where possible collected from the wild); 2. heritage variety; and 3. modern F1 hybrid cultivar. Samples of each strain in a trial were sent to the Rowett Institute of Nutrition and Health for analysis of phytochemical content with a focus on compounds linked to prevention of diabetes, cancer and heart disease. In addition, each strain was scored for productivity by weighing a specified portion of the crop. Plant health issues were recorded to see if certain strains display greater resilience and, as noted above, blind tastings were conducted to assess flavour preference.

During 2015 the focus on brassicas and celery has generated relatively few new results for productivity. Brassica trials have been conducted every year and additional data on productivity was not needed. For the celery trials the only data available at the time of writing is presented below. These data are from a sample of eight plants of each of the three strains grown at the Royal Botanic Garden Edinburgh by the Edible Gardening Project. In each case only the above ground parts were weighed:

Wild Celery – 368g, 162g, 178g, 152g, 133g, 130g, 159g, 51g with a total of 1,333g and a mean of 167g

Heritage Celery – 197g, 405g, 155g, 428g, 141g, 49g, 283g, 289g with a total of 1,947g and a mean of 243g

F1 Hybrid Celery – 175g, 197g, 240, 436g, 350g, 147g, 427g, 412g with a total of 2,384g and a mean of 298g

These results fit an expected pattern in which F1 hybrids are most productive and wild ancestors least productive. Domestication is to a large extent driven by a desire to increase productivity so we would expect wild plants to be relatively unproductive. In the case of F1 hybrids the crossing of two genetically distinct strains to create the F1 hybrid is the source of what is known as hybrid vigour. One manifestation of this is increased growth, and this explains why F1 hybrid strains are so commonly available to the home grower.

During 2016 the investigation of edible wild plants as novel crops will move away from Scottish native crop wild ancestors. We plan to grow trials of black nightshade (Solanum nigrum) collected in the UK and from a seedbank in Holland. This species is a weedy member of the potato family that is semi-domesticated in some areas (particularly Africa) and grown as a versatile crop that has edible leaves and fruits. In Scotland it is not native, but we are confident it will grow here as our herbarium has numerous examples of this species collected in Edinburgh and elsewhere in Scotland over the last 100 years or so. Most of these are garden weeds or accidental introductions with imported products. As a result many of the records are from Leith, a major trading port in the past. To start this exciting new project off with some UK origin seeds the Natural History Museum was contacted and has kindly supplied a selection of fruits removed from recently collected herbarium specimens (see below). It will be interesting to see if these seeds are still viable, but if not the Dutch seeds will enable a range of trial plots to be grown so keep your eye out next spring in the area adjacent to the Queen Mother’s Memorial Garden.

Seeds of black nightshade supplied by the Natural History Museum from recent herbarium collections.

Seeds of black nightshade supplied by the Natural History Museum from recent herbarium collections.

Nov 172015
 
Male blackbird eating berries of common yew Taxus baccata.

Male blackbird eating berries of common yew Taxus baccata.

The idea that a story about a male yew tree producing a female branch would go viral and attract massive media attention would have seemed highly unlikely a month ago. Nevertheless, this is exactly what happened with the Fortingall Yew when it was noticed that a group of three yew berries (technically called arils) were present on a branch within this otherwise male tree. The first coverage was in the Scottish Mail on Sunday on the 1st November and then most of the major newspapers picked up the story during the following week. To date the story has featured around the world and has made the pages of such unlikely publications as The Spectator and The Economist. There was even an appearance on the satirical BBC programme Have I Got News for You.

One result of all this media coverage has been the many comments from people. Among these there have been some intersting observations of the poorly understood phenomenon of partial sex change in yew trees. At least one person pointed out that this is not a new observation, although that was never claimed. A Polish study published in Dendrobiology in 2004 that looked at nearly 3,000 yew trees found that less than 1% had both sexes on one tree. Yews with both sexes have been reported from time to time for over 100 years, but they certainly seem to be pretty rare.

Perhaps the most exciting comment was from Janis Fry who got in touch to say she had seen a female branch on the Fortingall Yew back in 1996. From comparing notes it seems likely we have both observed the same branch, so this raises the possibility that the branch has been female since at least 1996. Janis said that she has been studying yew trees for over 40 years and in all that time she has only seen 12-15 trees that display both sexes on one tree.

Yew berries showing the distinctive fleshy aril that surrounds a single seed.

Yew ‘berries’ showing the distinctive fleshy aril that surrounds a single seed.

Although the mechanism of sex determination in yew trees is unknown, scientists have noticed a correlation between conifers that have the sexes on separate trees and the production of fleshy fruits. Yew is a nice example of this. The fleshy aril is evolved to attract birds with its bright red colour. The theory is that the reproductive benefits of having animal dispersed seeds outweighs the cost to the female tree of investing so much energy in producing large edible fruits. It seems that the yew ‘berry’ is a key product of evolution that enables yew trees to have separate sexes. There are other examples of this strategy in the collections at the Botanics. The Chilean Plum Yew (not a yew, but a distantly related conifer in the genus Prumnopitys) normally has the sexes on separate trees and has edible green ‘plums’ on female trees. Curiously, a male tree here at the Garden was observed to produce a few fruit in recent years, mirroring the situation with the Fortingall Yew.

All this interest in yew trees and their curious sexual habits has been a golden opportunity to promote the ongoing project to establish a yew conservation hedge around the Garden. This work involves the phased replacement of the existing hedge with a new yew hedge composed of around 2,000 plants raised from wild collected seed and cuttings that will encircle the Garden and provide a resource for research into yew genetic diversity across its wide native range. Ultimately, trees could even be returned to areas where yew is under threat of extinction.