Tar Spot

Not the sycamore leaf, but the black spots. It is Rhytisma acerinum or Tar Spot. It is an ascomycete fungus and more specifically the fruiting body of the fungus. It doesn't harm the tree.

Great Reedmace or Bulrush?

Bulrush, I hear you cry. As in 'Moses in the Bulrushes', the painting by Sir Lawrence Alma-Tadema?
It is a popular belief that up until the time of this painting the common name for this plant, Typha latifolia, was Great Reedmace, but that his popular painting misidentified them as Bulrush and everyone subsequently jumped on the bandwagon.

This is not true of course, as it was being referred to as bulrush long before Sir Lawrence was born. Furthermore, he actually called his painting 'The Finding of Moses'. The term 'bulrush' actually comes from the old English word for papyrus, as in Cyperus papyrus, which is what Moses' floating cradle would most likely have been made of and found amidst.

The BSBI hedges its bets by saying that bulrush and reedmace are both acceptable as common names for Typha latifolia. It belongs to the angiosperm or Magnoliophyta division of the plant kingdom (cf. gymnosperms) - in other words it produces seeds that are enclosed and contain endosperm (food for the developing seedling). It is a monocotyledon (cf. dicotyledon) which means when the seed develops the shoot only has one leaf. Finally, it is in the order Poales, which contains all the grasses, sedges and bromeliads.

Mute Swan

Today's species is another familiar one: the mute swan or Cygnus olor. It is the commonest swan in the UK and named because compared to the other swans (whooper and bewicks) it isn't as 'vocal'. The black swan of Australia is it's closest relative, phylogenetically speaking. 
The monarch 'owns' all 'unmarked' swans, though this right was extended to the Dyers' and Vintners' Companies in the fifteenth century.
The knob at the top of the bill swells during the breeding season on males only, helping to tell them apart. The males are called cobs. They generally pair off and stick together for life, consequently they are a symbol of fidelity. The most famous mute swan is the 'ugly duckling' in the story by Hans Christian Andersen.

Mallard

We popped into the Arundel Wildfowl and Wetland place en route to Chichester today and were dismayed to discover that our Family membership didn't allow us all in as it only covers two adults and two children 16 years old or under. So we had to fork out £9.95 for our eldest, which is the rather daunting student rate. As Matty pointed out: it's really somewhere only the affluent middle-classes would go. Fair enough. It's also a charity doing good work, my wife chipped in. So we paid up, plus some for feed, and had a lovely couple of hours pootling around the reserve.
There were of course some wonderful rarities, but how could one not start with the ubiquitous mallard: Anas platyrhynchos. The name 'mallard' is thought to come from various Old languages, meaning 'drake duck' but it's not very clear. The binomial species name means 'broad/flat nosed'.

And it really is found all over the place, barring Antarctica. It is in the Anseriformes Order and the Anatidae family. This latter contains most of our ducks, geese and swans - although the magpie goose, which turns up in huge numbers at Kakadu National Park in Australia's Northern Territory, belongs to a different family.
Numbers in the UK are swelled by a few winter migrants from Scandinavia and central Europe, but less so than in the past. They swell numbers by around 3%.
Mallard males have a bit of a bad reputation on account of their tendency to commit gang rape. Groups of unpaired males will sometimes pick out an unpaired female, or even another male, chase it until weakened and then copulate with it in turn. There is even a report of homosexual necrophilia, the submission of which won the scientist an Ig Noble prize.