The last time Richard Hughes showed in Glasgow, his work could be divided into two types. For the most part, he made immaculate sculptures of rather mundane, often unpleasant things. Roadsider (First of the Morning) was a perfect model of a bottle flung from a car window by a driver caught short between service stations. Cast in three stages from resin, everything from the yellow liquid pooled inside, to the blue plastic cap of the bottle, to the beads of condensation on its surface were absolutely realistic, utterly convincing. Even if you were allowed to pick up the art in galleries, you wouldn't want to touch this.

Hughes's second tactic was to make sculptures from the sorts of odds and ends he also makes sculptures of, as in Love Seat, a jumbled pile of mannequin legs, grubby long-johns and sports socks that, when seen from just the right angle, transformed into a hand making the peace sign.

Hughes still makes work such as this. At his first solo outing in New York earlier this year, he showed Crash My Party You Bastards, which looked like an attempt to recreate the aftermath of some very rowdy uninvited guests, but, viewed from across the room, resolved itself into a pouting teenager's face, forming a seedy update to Dali's Face of Mae West with its sofa lips.

But for this show, Hughes seems to have left behind the double-take transformations and casual trompe-l'oeil experiments to focus his attentions on the grimly realistic side of his practice, though there are still signs that this is an artist doing much more than meticulously crafting copies of the underwhelming items that catch his eye.

The walls of the main gallery space at The Modern Institute are dotted with little deflated balloons, all in rather sickly, faded colours, some with jolly faces printed on them.

This being Hughes, they're not balloons, but precise resin casts, and to underline the fact that these are made, not found objects, each one is pinned, impossibly, upside down, sticking up instead of drooping down.

These sad little reminders of a sad little party hark back to Hughes's long-running preoccupation with evoking dingy moments, but giving them a little nudge - in the past he has crafted discarded bike tyres, but looped them, impossibly, around gallery pillars - as if to suggest that there is magic to be found in overlooked episodes, or that we should re-evaluate those hazy memories of teenage years spent aimlessly mucking about.

In the next room, there's a sculpture of a roll of soggy carpet that's been left too close to a bonfire, so that one end is singed, and, thanks to a pulsing light inside, still glowing. If you hold your hand over the embers at the tip, it's a little warm, and there's even a faint chemical whiff in the air.

Like the 180-degree twist of the balloons, Hughes isn't just engaged in perfect model- making - the sculpture of a carpet roll looks like a sculpture of an oversized hand-rolled cigarette, right down to a bend in the middle, as if it's just been flicked away.

The rest of the works inside the gallery, though, are more prosaic, more straightforward. There's a filthy white tarpaulin banner, the sort you see strung up over a shop's signage announcing a closing-down sale, slumped on the floor, caught at the moment it fell from a set of four nails still firmly affixed to the wall.

Another faintly glowing cigarette end shows up, one step closer to reality than the carpet, this time on top of flattened cardboard boxes made of fibreglass and polyester resin.

Across the room, a single plimsoll sits unhappily, blackened with mould, with grass growing through its sole.

Technically, this is Hughes at his best - it is almost impossible to believe that the discarded cigarette isn't about to start a fire in the gallery, or that the abandoned trainer isn't soaked through with brackish water. And so, these pretty repulsive objects become incredibly attractive: the first reaction is to cringe, and think "Yuck!"; the second, which follows quickly, is to get in close, inspecting the works from every angle, spotting the mark of a paintbrush here, an unrealistic sheen there, wondering how on earth Hughes manages to make these things.

This is something Hughes has in common with Robert Gober, the American sculptor best known for his fastidious sculptures of sinks, bundles of newspaper and body parts, or, even, with the hyper-realistic figures made by Duane Hanson and Ron Mueck.

But where those artists prompt an urge to inspect, to work out the techniques of not-quite-perfect reproduction, they lack Hughes's knack for bringing to mind a sense of time captured, the idea that the rotting trainer has been stumbled over while tramping across a patch of waste ground at the edge of a city, or that the cigarette has been dropped in the middle of some furtive conversation round the back of a suburban supermarket.

In the end, these pieces, though apparently more simple than the temporary illusions Hughes makes from piles of junk, or the subtle twists he adds to some of his recreations, offer the greater rewards.

Outside on Robertson Street, Hughes turns his gallery practice on its head with a public work, set in a lot awaiting redevelopment. It is monumental in scale, and, made of bronze, in its materials. Inevitably, though, Hughes has made a memorial to an apparently ordinary incident, casting a stubby, leafless tree which has grown through the burned-out back of an abandoned plastic chair. Out in the street, and viewed from a distance - the lot is fenced off - the thing appears to be absolutely real, if rather unlikely. And it infects its surroundings: the traffic cones that have been chucked over the fence could be by Hughes, and there's even a plastic bottle lying by the gates, with a blue cap, just like Roadsider.

It's a funny reversal of the old joke, in which a gallery-goer ignores the art, inspecting instead the fire extinguishers and light fittings, but, more than that, Hughes really has managed to question the status of the junk littering the city-centre patch he's invaded with an impossibly real, but obviously fake sculpture, in just the same way that his work inside the gallery ask us to look again at the abandoned artefacts he chooses to recreate.