Chronodendron

A journey along the ever-branching Tree of Time

[chronodendron-blog]

I had another fight with my _Schistura_ loach today. He spent a little time out front, and I thought I could sneak up on him to get some photographs. Once again, he was too swift for me, and all I got were some greyish blurs. But the tiger snail was much more accommodating and I got some excellent shots of its shell, to supplement the pictures of its underside from earlier in the month. Also, I think one of its eyes is visible in one of these shots - either that, or it's a bubble. But I think it's probably an eye.

The first thing I want to talk about is the shell damage which is clearly visible in these shots. Snails are pretty stupid, on average, but this case really highlights that lack of brainpower. I have three large flat building stones in my aquarium, arranged in such a manner that the bottom feeders have several hiding places. There's a "cave" and an "overhang", and at either end there are little sheltered spaces where the stones come close to the glass. Algae seems to thrive around the edges of the stones, particularly where they contact the glass, and the snail has spent a lot of time in those areas. When it was new, this did not present a problem, as it was small enough to fit in these spaces easily. But it has been steadily growing - and at some point, it became too large to fit in those spaces without scraping its shell against the rough stones. This did not stop it from trying, though, and over a period of several months it has scraped the periostracum right off of the apical portion of the shell. In a few shots you can actually see the narrow band of new periostracum which is beginning to creep back over the exposed calcium carbonate. You can also see the snails viscera as a vague pinkish blur through the transparent portion.

The African tiger snail is a member of the genus _Neritina_, a relatively large genus which is primarily marine but has produced several lineages that have adapted to brackish conditions, and have in turn produced a few strictly fresh-water species. This species, _Neritina natalensis_, belongs firmly within the latter category, and although it is from tropical Africa it can adjust well to cold water aquaria such as my own. In the wild it is being over-exploited as a food source, but it breeds well in captivity and is one of the more commonly available species. _Neritina_ is part of a modestly-sized family, the Neritidae, named after the marine genus _Nerita_. Many nerites are important food animals, some of the marine species have been key items in the diets of coastal peoples throughout the world since humans first started acting like humans. Pre-agricultural societies have tended to leave behind refuse heaps called "middens", these build up to enormous sizes over hundreds of years of continuous use, and in many parts of the world nerite shells make up a sizeable percentage of midden contents.

Finally, you might notice a difference between the patterning on the upper and lower portions of the front of the shell. This is due to the snails growth; the upper portion represents how large the shell was when I purchased the snail, and everything below the "dividing line" has grown since that time. In the store, this snail was in a heated aquarium; mine is unheated. I presume that its subsequent growth has been much slower that it would be in a heated environment, hence the slight difference between the two regions of shell. It would be a stunningly beautiful shell if not for the damage to its apex.

[chronodendron-blog]

Throughout my life, there have been plants which I know by sight, but never learned their names or any other information about them. I could see one and remember several dozen other instances of seeing it, clearly recalling many of its features, but if asked what it was all I could provide would be a brief description. These pictures show one of those plants, which is still proving just a little vexing.

The genus of this plant is _Pyracantha_ and there are only about six or seven species, which makes it a rather small genus when compared to its close relative _Cotoneaster_. All these species are known as "firethorn" and are extremely difficult to tell apart from one another; leaf shape and the extent of serration in the leaf margin is supposed to be the easiest way, but with my research so far I haven't been able to narrow this one down to the species level. Fruit colour is useful in distinguishing between the wild forms of the species, but in cultivation each species has produced varieties which display the fruit colours of the other species, so it's useless for my purposes. This could be _Pyracantha angustifolia_ (native to southern China), _Pyracantha crenulata_ (native to the Himalayas), or an orange-fruited cultivar of _Pyracantha coccinea_ (the wild red-fruited plant is native to Mediterranean Europe and the Middle East).

The biggest difference between firethorn and _Cotoneaster_ is the presence of thorns (no shit?), and my oh my what thorns they are. As a child, I saw this plant being used as a hedge in the part of Surrey where I lived (Surrey, British Columbia, not any of the other Surreys), and those huge thorns made a big impact on me. I would freak out if I saw other kids trying to pass through a hedge, regardless of what sort of plant formed the hedge, because I was afraid of those wicked thorns. They really are impressive things, more like cactus spines than rose thorns in shape. I wonder if you could play music on them like you can with a cactus.

Firethorns are in the Maleae tribe of the Rosaceae family, together with apples and rowans and hawthorns and a bunch of other cultivated plants. Like their close relatives in the genus _Cotoneaster_, _Pyracantha_ species are evergreen, keeping their distinctive leaves throughout the year. _P. coccinea_ is more tolerant of dry conditions than the others, which makes me lean towards thinking the plants in these photos might be an orange-fruited cultivar of that species. I'm fairly certain that the ones I grew up seeing on the Coast were one of the Chinese species, as they grew large and imposing in the wet environment there. These photos were taken at the Penticton Rose Garden, the close-ups of the densely-packed pomes show a separate smaller specimen than the other photos (for some reason, almost all the fruit from the larger specimen was dessicated, while that on the smaller one was still in good shape).

[chronodendron-blog]

Sometimes, animals like to party, too.

What you are seeing here is an interaction between two very different organisms, the European mountain-ash _Sorbus aucuparia_ (except for the last two photos, that's a different tree) and the Bohemian waxwing _Bombycilla garrulus_, with rather different benefits for each participant. In the rest of the English-speaking world, _S. aucuparia_ is known as the rowan tree, and that is the name I prefer to use for this species, but here in North America the standard term in the horticulture industry is "European mountain-ash". I've been greeted with blank expressions when I've used the word "rowan" around landscapers, so I've had to start using the other name despite its technical inaccuracy (the word "mountain-ash" properly refers to the native North American species of the genus _Sorbus_, not the European species). Waxwings are often called "those noisy little birds", and are one of the most noticeable small birds in this region, forming large flocks which swarm about from place to place in search of berries.

The _Sorbus_ species are members of the "apple tribe" Maleae within the very large Rosaceae family, and their fruit are pomes (like apples and pears, the outer flesh is actually derived from flower tissue and it's the "core" which represents the true fruit). _Sorbus_ fruits contain high levels of sorbic acid (surprise surprise) and taste very bitter to human beings. Birds are not phased by the astringency however and these fruits are a valuable source of nutrition for many species; they remain on the tree all Winter long, and provide one of the most steady food sources for non-migratory and irruptive species. When the waxwings sweep through an area during the course of their nomadic wanderings, they can strip entire trees within a week or two.

There are two waxwing species present in British Columbia, the cedar waxwing _Bombycilla cedrorum_ and the Bohemian waxwing _Bombycilla garrulus_. The cedar waxwing is a migrant, only arriving here in the Spring and departing again in the Autumn, but the Bohemian waxwing lives what is called an "irruptive" lifestyle - they stay in one area until the food runs out, then they all pack up and move somewhere else, and repeat the process ad infinitum. Large flocks of them can be seen all over this valley, they have adjusted well to suburban landscapes and particularly benefit from the large numbers of _Sorbus_ and _Crataegus_ which have been planted since colonization. Identifying features of the _Bombycilla_ genus include an erectile crest on the head, red-tipped feathers on the wings (hence the name "waxwing", as early naturalists were reminded of sealing-wax when observing the little red dots on the feather tips), and a yellow bar at the tail tip (except in the Japanese species, which has a red bar - but they're far away so I'm ignoring them here). The Bohemian waxwing has a reddish-brown crown and a smaller black mask than the cedar waxwing, and is more grey than brown in the body plumage. It also lacks the yellow highlights on its flanks and belly. It is the larger of the two species.

So, why have I equated the pictured interaction with "partying"? As mentioned, rowan berries provide needed nutrition for the birds, and the seeds of the rowans are spread in the bird's feces, so both species do directly benefit from their interaction. But the waxwings have another reason for swarming over these trees - the berries slowly ferment throughout the season, and when the birds pluck them and store them in their crops, they undergo rapid fermentation and essentially turn into awful bitter wine right in the bird's throat. The bird then swallows this, and spends the next little while drunkenly twittering away in the tree tops and veering around hilariously when it attempts to fly. These guys weren't all that tipsy, because they could still avoid trees and other obstructions, but they were weaving around with much less precision than would be optimal. I probably couldnt've got so close if they had been completely sober.

[fuckyeahdinoart]

morning thaw by ~DeEtta

[chronodendron-blog]

Thirsty little guy.

[chronodendron-blog]

This handsome tree is extremely interesting to me for three main reasons, but a fourth reason is just how pretty it looks. I love interesting bark textures on trees, and this "species" has some of the most unique bark to be found in my valley. The weird little morning-star-lookin' seed-balls only add to its quaint appearance.

So, unless this is a California sycamore (_Platanus racemosa_), which I highly doubt, it is almost certainly a London plane tree, formally called _Platanus x acerifolia_ due to its maple-like leaves. That little "x" in there indicates that this is a hybrid, not a naturally occurring species, but interestingly (and the first main reason why I like this thing) it is a fertile hybrid and can reproduce amongst itself as if it were a true species. The role of interspecific hybridization in evolution has been downplayed for the last 60 years or so, but the literature is full of examples of species whose unique traits are due to ancient hybridization - it is a particular interest of mine. According to my research, the original hybrid lineage first formed in Spain in the 1700's, in a garden where an Oriental plane tree _Platanus orientalis_ and an American sycamore _Platanus occidentalis_ had been planted right next to one another. Since that time they have been propagated widely; the little seed-balls are made out of hundreds of achenes, dry capsules with bristly hairs which catch the wind and can be blown very far from the parent plant, so it tends to naturalize in regions where it has been planted. New hybrid lineages were purposefully established during the 20th Century, from the same two ancestral species, and these new lineages are interfertile with the original _P. x acerifolia_ lines.

The second reason I've taken a liking to these trees is that they are part of a very ancient group, the Platanaceae. Flowering plants (Angiosperms) are thought to have first diverged from the various Gymnosperm groups during the Triassic or earliest Jurassic, but the earliest Angiosperm fossils are known from the early Cretaceous. However, many of these fossils include plants which are clearly members of living groups - there are Cretaceous yuccas and magnolias, and also Platanaceans. The genus Platanus itself is known from a 115 million year old fossil, and that just blows my mind. One of the most fascinating aspects of evolution, in my mind, is how some genetic lineages remain steady for tens of millions of years or more. The mechanisms behind this are poorly understood - mutation rates tend to be pretty constant, as DNA is DNA no matter what sort of organism it is building and always has the same instability over time, so when an organism remains almost unchanged for so long there must be some pretty heavy selective pressures keeping them that way. People often think that evolution means that creatures change when they have a reason to change, but really it's almost the exact reverse - genetic errors build up constantly over the generations, and it takes external selective forces to prevent cumulative changes from shattering a population into an array of daughter species. So, as a new hybrid daughter of two living fossils, the London plane is doubly fascinating to me.

But the particular specimen shown in these photographs has a third point of fascination for me - together with its companion further down the street, they are among the oldest living trees in my town. The site on which they grow was the location of the first farmhouse on this land, built by the pioneering Ellis family in 1915. They planted these trees along with some sort of fruit tree which I can't quite identify - I'll post the pictures of those another time - back when this entire part of the valley was still being used for subsistence by the native people. In a way, these trees are the living embodiment of the transition between the older face of the Penticton area and the new. I'm more fond of the old than the new, but this isn't the place to discuss such things.

There are a lot of London planes growing in that region of town, and I wouldn't doubt if they're all descended from the two ancient specimens growing on that historical site. I'll be revisiting these later in the year to discuss their leaves.

[chronodendron-blog]

I have no idea how to identify this fungus. Is there an equivalent to dichotomous keys for fungi? The mysteries of life.

The tree that this fungus is growing in is a rather large specimen which I am 90% sure is a hawthorn, a member of the genus _Crataegus_ in the “apple tribe” Maleae of the Rosaceae family. It’s a large genus with a lot of diversity between its species, I photographed about five or six specimens yesterday which belong to at least two separate species (but it might be three). I want to do a little more online research before discussing those trees, though, as right now my knowledge of hawthorns is pretty much limited to “everyone plants the thornless varieties now” and “jeeze those things have huge spurs”. Though not all the species do. Huh.

The hole that this fungus is protruding from is located about six and a half feet up, so I had to raise the camera above my head for the second shot. I had no idea the fugus continued that far into the hole until after the picture was taken; it’s just a fluke that the autofocus rendered such a clear shot on that first attempt. I’ll be revisiting this tree (and many of the trees I’ve photographed this Winter) throughout the coming seasons, so I’m interested to see what time of year this fungus produces its fresh fruiting bodies. The actual “main body” of the fungus is a swarm of microscopically-thin but extremely long filaments (the mycelium) which are located within the tissues of its host - these visible parts are just the reproductive structures, formed when two individual mycelial strands (hyphae) merge together at their tips, a process analogous to fertilization. I’ll be keeping an eye out for interesting fungi throughout the course of this project.

[chronodendron-blog]

This is a duck. Quack.

The mallards (_Anas platyrhynchos_) in this area are extremely tame. This photo was taken in the Penticton Rose Garden, which is one of my favourite places to visit during the Spring and Summer. The ducks were all lounging about beneath the biggest hawthorn tree I've ever seen, a yellow-fruited type (well, the fruit was yellow when it was ripe - right now it's all withered after a Winter on the tree and has turned an ugly reddish brown, you can see fallen fruit around this drake). I snapped this photo moments after this guy bit a female right on the ass, I thought he would go after another but he didn't like me taking pictures and refused to bully again.

[fuckyeahdinoart]

Prenocephale prenes by ~T-PEKC

[chronodendron-blog]

Aaaand I figured out how to do it :P .

This is such a cool interpretation of the strange features of pachycephalosaurs - instead of the traditional "head-butting" interpretation, this artist appears to have envisaged the thick head-shield and shock-absorbing vertebrae as being part of a burrow-sealing adaptation. There are ants in the contemporary world which use their swollen heads as doors to block their tunnels, and the wombat (genus _Vombatus_) has an armoured rump which it uses for the same purpose. So this idea has plenty of real-world precedent.

[chronodendron-blog]

When I first came to the Okanagan way back in '03, I noticed this plant growing in a wide variety of places and immediately dismissed it as a low-growing variety of holly (genus _Ilex_). For many years I didn't question this identification, until one day I mentioned "those holly bushes" to my father and he immediately told me the correct name of the plant - Oregon grape. However, it turns out that the name of the plant was the only thing he had correct - because he went on to tell me that "it's extremely poisonous, the Natives used to dip their arrowheads in the juice of the berries". I do not know what plant he must have been thinking of, or if poison arrows were even used in this part of the world at all, but I now know that Oregon grape is far from poisonous.

_Mahonia aquifolium_ is not closely related to actual grapes (they're both Eudicots but otherwise they are as distant as can be), but is named for the small round berries which have a resemblance to Concord grapes. These berries have always looked dark blue to my eyes, but according to online sources they are actually black with a white bloom on the surface (that is to say, a thin coating of a powdery substance which makes them appear to be lighter in colour). This species also is not related to the genus _Ilex_, which is the only genus in its own family, Aquifoliaceae, in the Aquifoliales. Instead, _Mahonia_ is a very close relative of the barberries (genus _Berberis_) in the Berberaceae family within the buttercup order, Ranunculales. Hybrids between species of _Mahonia_ and _Berberis_ have been documented, and for that reason some specialists consider _Mahonia_ to be an invalid genus and instead place all its species directly within _Berberis_. I hope that this never becomes official because _Mahonia_ is such a fun word to say.

The leaves look amazingly similar to those of European holly (_Ilex aquifolium_), but the flowers are very easily distinguished - those of holly are white, with a slight yellowish tinge on male plants, and have four noticeably distinct petals; those of _M. aquifolium_ are bright yellow and bear six stamens, six petals, and six sepals. Yes, they are Flowers of the Beast. Tremble, ye, and despair. In the Winter, many of the leaves of each plant will turn a deep red colour; I have observed much variety in the precise shade of red involved, from a dingy burgundy colour to bright cherry red and almost everything in between. I've only rarely seen an entire plant turn red, usually many of the leaves stay green throughout the Winter.

The berries are not only edible, but considered delicious by many (and repugnant by others). Several people have told me stories about trying Oregon grape jelly, and I've also been told that it takes so many of the tiny berries to make any amount of jelly that gathering them is a tedious chore. One friend has told me that the fresh berries smell of fish oil when crushed, but I haven't tried it myself so I cannot verify that anecdote. According to online sources, the roots of the plant have been used in herbal medicine to treat stomach problems. This stuff grows everywhere around here, it's something that everybody sees every day and probably never thinks about. I've always liked it, but when allowed to grow large and then pruned back to a shorter height it can look rather scraggly. All these photos were taken alongside one short path, behind the lockworks on Main Street.

[chronodendron-blog]

The two suckers weren't the only recalcitrant fish today. I had one Hell of a time trying to get a shot of my _Schistura_ loach, and finally succeeded in getting him to sit still long enough... only to have this smartass camera decide to jerk me around. It's been a pain lately, the flash won't do what I set it to do and there is no manual focus, only autofocus... and autofocus is like autocorrect, it's a little too helpful. It refused to focus on the opening to the ornament from which the loach was peeking, instead focusing on various other features around that opening. I've included the clearest of the shots here, but the face of the loach is almost indistinguishable.

The genus _Schistura_ is a speciose genus of "river loaches", the fusiform open-water members of the family Balitoridae. This is in contrast with "hillstream loaches", also in the family Balitoridae, which are flattened and pleco-like in their general outline. Hillstream loaches are also pleco-like in habit, having a sucker with which to cling to the surfaces which they scrape for their dinner. At the pet store, this river loach was labelled as "hillstream loach", with no further qualifiers to help me identify it. It took almost an hour of trawling through FishBase to figure out what genus I was dealing with, but I haven't found an exact species match - _Schistura_ contains very many species, and of those listed on FishBase less than half have photographs online. The body of this fish boasts a lovely pattern of light and dark grey stripes, with a white belly and black highlights around the fins. It's an extremely skittish fish, reacting explosively to observation. I had several "false hope" moments where it was sitting still long enough for the stubborn autofocus to finally render a clear view - only for the loach to piss off into the pleco's stronghold the moment I hit the button. I had lots of shots of recently-disturbed gravel, but none of the fish.

The first shot is another of the _Pangio_ loaches, there are three and all of them are quite comfortable being observed when they are amongst their rootmass. They're used to my presence but when a stranger is present they burrow right into the gravel to get away. I don't understand exactly how they tell who is watching them, or why they've decided I am "safe", but I have a hypothesis. It's probably familiarity with my voice, I've noticed that they don't go into deep hiding when a stranger remains quiet, only if they speak, so I assume that our voices are enough to vibrate the aquarium glass in a way which produces sounds that the loaches can recognize. Loaches are Cypriniformes, after all, so they do have very sensitive hearing.

The last shot is another testament to why I need a better camera for aquarium shots - you can see the buggy little machine in reflection. But I like how both the big pleco and the little _Ancistrus_ show up relatively clearly, I couldn't get many shots of them so I should make use of what I was able to shoot. The little bastards are all out in plain view now, maybe with patience they'll eventually get used to being photographed.

[chronodendron-blog]

This animal was much, much more difficult to photograph than the bamboo shrimp. I am not happy with any of these shots, but it was the best I could do on this attempt and I wanted to post something today. The little lady is very shy, I always have trouble observing her because she watches me right back and bolts as soon as I get too close. This time, she seemed to view the camera as a threat, because she would come out of hiding the moment I put the camera out of sight but would bolt again as soon as I brought it back.

Her name is Schwim and according to the pet store she is a "spotted ancistrus". The genus _Ancistrus_ consists of the bristlenose plecos, it is only the males of these species which grow the distinctive "snout full of tentacles" from which they derive their name. I refer to Schwim as "she" because there is not the slightest trace of bristles on this fish - there is a high probability that "she" is actually a male who simply hasn't begun to mature yet, but this fish has more than doubled in size since I bought it and there's still not the least bit of face-tentacle to be seen. It is still a young fish, though, so if it turns out to be a male I will probably have to apologise.

I am not certain of Schwim's exact species, _A. cirrhosis_ looks similar but has more clearly-defined spots, while _A. pirareta_ is also very similar but just a little off. According to the brief research I did before posting, there are quite a lot of species in the genus which are present in aquaria, and many of these species are only distinguishable by minute features of the fins and dermal plates. She is a diligent algae eater, after my standard pleco grew too large to be of any use I introduced her and she almost immediately beat back the incipient infestation of greenery and restored the tank to its state of equilibrium. Like most of my aquarium denizens, this fish is technically a tropical but is thriving in the unheated environment nonetheless.

Neither she nor the standard pleco liked the camera much. They're both out and moving around now, but I'm sure that if I brought the camera out again they'd both nestle right back into their cave (it's just three building stones stacked in a cave-like manner). I had to pull the aquarium away from the wall to get those in-the-cave shots and they still turned out crappy. Better luck next time I hope.

[fuckyeahdinoart]

Calm by *potsmokindino

[chronodendron-blog]

I love this dinoart blog, but I'm still a little clumsy with tumblr and I haven't figured out how to follow a feed unless it has a big ol' "FOLLOW" button.

[chronodendron-blog]

This is a strong beginning for my quest to identify all the living things which I share my life with. Only a few hours after documenting the tiger snail (Neritina natalensis) in my aquarium, I discovered that the filter-feeding shrimp which I had assumed to be long dead was actually still alive, and willing to sit still long enough for some photographs. I had purchased two of these animals from the local pet store sometime in the late Spring or early Summer, they were listed simply as "rock shrimp" and the employees at the store did not know much about them other than the fact that they feed on suspended particles in the water and can tolerate low temperatures. I have an unheated aquarium, and I was a little leery about introducing them because they were in a heated environment at the store, but they did well for several months. However, in September one of them died, and throughout the course of the Autumn the remaining shrimp was sluggish and retiring. I stopped seeing it at all in early December, by January I assumed it was dead (the other shrimp was devoured by loaches within hours of its death, so I wasn't expecting to find any remains).

According to subsequent research, this animal is formally called "Moluccan bamboo shrimp", _Atyopsis moluccensis_, although its range is much wider than just the Maluku Archipelago, stretching from the Malaysian mainland throughout the Indonesian islands east as far as Samoa apparently. They tend to be restricted to high altitude regions within that range, which explains their cold tolerance. I know from personal observation that these crustaceans are voracious filter feeders, their first pair of limbs are modified into fanlike straining structures with which they collect food particles from the open water. When both were still alive they tended to stick together, but the big one would bully the little one, climbing on top of it during feeding times as if trying to take control of the food source. Both individuals had a bad habit of perching on the filter tube, so that I would have to dislodge them before removing the filter during cleanings - but, as already noted, this specimen has been in hiding for months.

The fish in these pictures is one of my loaches, Steve-Dave. I have three members of that species, they are definitely in the Kuhli loach genus _Pangio_ but I can't identify their exact species. The only species on FishBase which matches them in colour and form is _Pangio fusca_, except that _Pangio fusca_ lacks pelvic fins (that is one of its key distinguishing features) while these loaches have conspicuous pelvic fins. The store listed them as "Black Kuhli Loach" one year and "Red Kuhli Loach" another year, so that's no help. They are very entertaining fish to watch, avid burrowers who respond immediately to human presence.

The plant is a Java Fern, _Microsorum pteropus_, which is not really suited to a cold water aquarium but has been growing fine for nearly a year now. The shrimp has most likely been hiding in the dense tangled rootmass, which also tends to harbour the _Pangio_ loaches when they aren't burrowed into the gravel.

[chronodendron-blog]

Until this year, I had been under the impression that _Ailanthus altissima_ was some type of sumac tree. I had wondered why some "sumacs" bore samaras while others bore these big bud-like clusters of fuzzy fruits. Now that I understand the separate identity of these trees, I find myself marveling at their superficial similarities. The picture on the left is a male _Ailanthus_ (you can tell it's a male because it lacks samaras), while that on the right is a staghorn sumac (Rhus typhina). They do have very similar shapes, and in the growing season their leaves and flowers look almost identical. The easiest way to tell the difference is the bark - that of the sumac is brown and tends to flake on older stems (young growth is really fuzzy, with a velvet-like covering of fine trichomes), while the Tree of Heaven has greyer smoother bark with many lenticels or fissures resulting from fusion of lenticels. The difference between the fruits is only useful when fruit is present - the male _Ailanthus_ bears no fruit, for obvious reasons, and must be identified by features of the bark and leaf scars.

Sumacs also bear large compound leaves which leave behind triangular leaf scars; the bud is a different shape than that of _Ailanthus_ and is easily distinguished with a little practice.

[chronodendron-blog]

I've just finished a horticulture course that I began last Autumn, and in December I did a project where I documented the different life stages of the Chinese Tree of Heaven, _Ailanthus altissima_, which is an invasive species here in my valley. Seeing as the purpose of this blog is identification of life forms, this seems like a good species to start with.

_Ailanthus altissima_ is a short-lived fast-growing tree, which spreads by winged seeds and aggressive suckering roots. An individual can grow several meters per year, beginning life as a simple unbranched stick which goes on to produce lateral branches the following growing season. The most distinctive feature of the tree is the triangular leaf scars on these unbranched stems - each scar has a bud nestled in the sinus, and this bud is what gives rise to new growth. This growth habit leads to a very distinctive branching pattern in adult trees, but the bark of the adult looks very different from the bark of young plants. The similarity is best observed by comparing terminal twigs of adult plants with young shoots - because they are the same sort of tissue, young and unweathered.

The leaves are compound, which is to say that each leaf consists of a stem with many small leaflets growing from it. The leaves look like twigs with many leaves on them, but they are single leaves and the entire structure drops each Autumn. The fruit is a samara, a dry podlike structure which is light and papery and is easily blown about by the wind. _A. altissima_ samaras have a distinctive twist to them, curling around their long axis, and the seed is a noticeable round spot at the center of the fruit. The bark of young branches has noticeable lenticels (small dotlike marks which act like pores) which merge together as the tree grows to form narrow pale-coloured fissures on the bark of mature trees. In Winter, when there are no leaves to make identification easy, these mature trees are often overlooked - it can be hard to realize that the young plants are the same species as these nondescript older specimens.

By 50 years of age, an _Ailanthus_ is quite old. The bark becomes very rough and gets colonized by algae and fungi, as the tree no longer produces its noxious defensive chemical (ailanthone) once it enters old age.

[chronodendron-blog]

So today my African tiger snail (Neritina natalensis) worked its way to the middle of the front pane of its aquarium home, putting itself on display. I had to take this opportunity to document it, so here are a few shots of the snail and the curious goldfish who kept coming around to investigate the camera.

In the first photo, you can see the snails antennae extended above its shell, as well as the tips of the radula within its mouth. There's a lot of snail-mouth here.

One of the black moors is investigating the camera while I'm trying to get a shot of the radula fully extended.

At this point I realized that the fish were watching me and started paying attention to them. The large standard goldfish is Big Frank. He's a jerk, shredding the plants and stealing the bottom feeder's pellets. He's also very noisy, sucking gravel into his throat and spitting it out for minutes at a time.

The silver one is Sparky. I don't know what breed he qualifies as, he has a veiltail and a rounded body shape but his eyes are sessile and he lacks any sort of "raspberry" structure on his head. I've seen some goldfish of his type around, sometimes silver and sometimes a coppery brown, but I do not know their name.

Frank, one of the shubunkins and one of the moors. I was having problems with the flash on this camera.

The flash problems really brought out the yellowish tint which the flesh of the snails foot has. It's not so obvious in the other shots.

I disturbed the snail by resting a finger of each hand against the glass in an attempt to steady the camera. It began to turn aside, and then retreated within its shell for a while.

Then I tried to get a shot of the radula fully extended, and eventually succeeded. The white structure visible within its mouth is the radula, the tongue-like scraper with which the snail rasps its algae prey off from solid surfaces.

At this moment, the snail is still on the front glass, attacking each little speck of algae one at a time. It must be able to smell the algae with those antennae, because it always steers directly for the small round patches. I will make a point of photographing it once it has left the glass, to show the most obvious distinguishing feature of this species - the striped shell.

[chronodendron-blog]

Testing the photo upload system.