Watching Donald Trump on TV early last week, I got a shock. He read from a teleprompter. He sounded like a statesman — well, sort of. He kept the boasting to a minimum. He held the taunts in check.

But what really threw me was his hair. Its color was as muted as the rest of him. I saw flecks of pale silver where I’d grown accustomed to showy gold. For a fleetingly presidential moment, he had a fittingly presidential mane.

The evolution of Trump’s coiffure over the decades has been widely noted and thoroughly documented. He has parted his hair on one side and then the other. He has combed it forward, swept it backward, swirled it like frozen yogurt, aerated it like cotton candy. In a brisk wind, it has been a pair of gossamer wings. During a tense debate, it has been a gargantuan sponge.

But less frequently observed is how much its hue changes, and I don’t mean from one year to another. I mean from one day to the next, in more incremental and mesmerizing ways, to a point where no two observers can agree on what to call it.

“Burnt-Cheetos auburn,” wrote Vanity Fair magazine’s Bruce Handy.

“Tuscan surprise,” said comedian Sarah Silverman.

While it’s tempting to explain these transformations as the lighting’s tricks or a colorist’s tweaks, I think there’s something more magical and mysterious going on. Trump’s hair is his mood ring. It signals how he feels — and who he wants to be — in any given instant.

A somber leader? Its brassiness fades, and there are shimmers of gray.

A big bully? It flares orange, in chromatic symphony with his face.

As Republicans descend on Cleveland for their unconventional convention, my questions go beyond how the GOP will pay for it, considering how many corporate sponsors have fled; if they’ll need to hire seat fillers for all the Republican senators and luminaries who have sent their regrets; and whether the final, formal platform will be more censoriously puritanical than the shaming of Hester Prynne.

I’m in follicular suspense, eager to behold the precise tinge of Trump’s hair, which has been compared to a tangerine, a nectarine and a grapefruit, though I could make an equally strong case for a lemon. He basically has a whole Whole Foods citrus section atop his head.

And we Americans have a situation of overdue justice, wherein a male candidate is finally drawing as much sarcastic, snickering attention for his appearance as so many female candidates have long endured. Just ask the woman whom Trump is running against.

From the early 1990s onward, Hillary Clinton confronted near constant commentary on her hair (along with her clothes), which was regarded as some window into her soul or mirror of her soulnessness. If she altered it too little, she was obstinate. If she altered it too much, she was pandering. Its length, lightness, waviness and accessories were all up for debate. A USA Today headline actually asked: “Hillary’s hair bands: Zippy or just dippy?”

Until Trump came along, men of a political stature comparable to hers were spared such sustained scrutiny, though they suffered moments of cosmetic reprimand — and hairy ones at that.

The news media harangued John Edwards for his $400 cuts, which now look quaint in the context of the $10,000-a-month hair maintenance bills that François Hollande, the French president, reportedly acked up.

I ask this sympathetically, as a man whose own hair will soon be a memory: What exactly is Hollande maintaining? He somehow ended up paying Rapunzel prices in a Rogaine situation.

Trump, on the other hand, has plenty to maintain, though the authenticity of that bounty has been disputed, with some onlookers divining sorcery where he insists there is only God’s miraculous blessing.

And his hair is more than just his hood ornament, or at least I reserve the right to assign it as much metaphoric resonance as Clinton’s was saddled with. To treat it as his prism. His proxy. Almost any question that you could ask about Trump you could ask in nearly identical language about his hair.

Is he/it emulating Vladimir Putin? To riffle though photos of the Russian strongman is to see a plethora of pigments from pewter to persimmon. It’s the same spectrum that Trump inhabits.

Does he/it reach too high and speak too loudly? Is there anything real there, at the root? Or is it all a glistening illusion?

If Trump’s ideology is unclassifiable, then so, too, is his hair. On the Ginger Awareness website, which extols the supposedly disproportionate achievements of the world’s glorious redheads, he is listed alongside Charles Darwin, Vincent van Gogh, Chuck Norris and Kathy Griffin. (It’s an eclectic pantheon.)

And orange, red and reddish foodstuffs are ubiquitous in descriptions of the fibrous canopy that begins at his eyebrows and rockets skyward without interruption, calling into question the very existence of his forehead.

“Pumpkin-pink” was what The New Yorker magazine’s Mark Singer called it. “A pumpkin having a nervous breakdown” was the take of Frankie Boyle in The Guardian, though I think he meant all of Trump, from halo to perfectly manicured (I’m guessing) toenails. “Salmon” has cropped up in several other assessments.

But then so have “wheat” and, in a patriotic vein, “amber waves of grain,” which would make Trump a blond. Caroline Mitgang, writing in Quartz, put him in that category, saying that his hair recalled “the nascent yellow of a baby chick.”

It certainly provides a semantic playground for fun-starved wordsmiths, who have found limitless diversion there. I was especially impressed with an appraisal that I stumbled across from The Daily Beast’s Michael Daly, who also noticed Trump’s shifting shades and pondered the semiotics of it all. I’m not the first at the nexus of his tresses and his temper.

Daly speculated that Trump had incorporated some gray, adding “a hint of George Washington to the Marilyn Monroe.” I detect some lingering Rita Hayworth and Lucille Ball in the equation, but — alas — no Abraham Lincoln.

And I’d like to note that Trump’s vice presidential search came down in the end to Newt Gingrich and Mike Pence, both with hair as changelessly white as Santa’s. Was he looking for someone to cede all color to him, and to show a constancy that he cannot? That’s my theory.

To grapple with Trump is to wrestle with his hair, and its tone on the convention stage may well augur his own in the weeks afterward. I’m not sure if that’s because it functions as a chameleon’s skin, syncing with his psychology and taking its cues from his context, or if we project onto it the color that coordinates with whatever he’s projecting at us.

Probably he’s just using that mess on his head to mess with ours.