The day before the Oregon Trail, Coco asked the other families in Ms. Harper’s class if she could join up with them. “Do you need a baby?” she asked the Murdochs and the Hancocks, the Bakers and the Blackthorns. “Or an adolescent?”

“No,” they said, if they bothered with her at all. Even though it was still regular school until tomorrow, the families were already insular and protective, clumping around desks between subjects.

“Aren’t you a matriarch yourself?” the Blackthorn matriarch asked.

“I don’t want to be,” said Coco. “I want to be a kid.”

“That’s stupid. Ms. Harper says we have to accept our station.”

“Yeah,” said the Blackthorn son, who blew his nose on his math worksheets. “Matriarchy is an incredible honor. Women rule.”

“Want to trade?” Coco asked.

“Doy, no.”

None of the girls assigned as daughters were interested in becoming matriarchs. Or at least they wouldn’t admit it to Coco. The best option was to join the Culver family, who offered her the role of an ox.

“You can pull our wagon,” said Alex, the Culver family patriarch. “If you can find another ox, we’ll yoke you. It’ll be super.”

What she wanted to be was a boy. Like Devon or Alex, but nice. She wanted to wear short pants and follow behind a party, providing for anyone who was hungry. She wanted to be a smooth-faced, short-haired colonial boy.

At home that night, Coco stuffed yellow felt triangles with dry grass for horns and affixed them to the cap of her headgear. She prepared a poncho that simulated the powerful shoulders of an animal and tied a piece of rope to her belt for a tail.

“Coco,” her mom said. “I thought you were a matriarch?”

Lately Coco hated the sound of her own name, which was like a pet’s name or the name of a girl with makeup in a Western saloon, embarrassingly girlish, the verbal equivalent of balloons stapled to her chest. She twitched like she’d been hit. “I used to be.”

“You look . . . You look like . . . I don’t want to say it.”

“What?” Coco struggled to speak clearly. Although her headgear was for night use only, she’d hooked the mouthpiece into the metal tubes on her molars. Otherwise the cap didn’t stay taut on her head. “What do I look like?”

Her horns flopped over her eyes. Her mom didn’t answer.

The next day, all four fifth-grade classes lined up at the head of the Oregon Trail. Each class was divided into six families of three or four members. People were meticulously dressed. The matriarchs wore full hoopskirts and aprons, bonnets and bodices with puffy sleeves, colonial dirt rubbed purposefully on the hemlines. The fathers and uncles wore leather vests and hats; the boys wore britches. The families pulled red wagons and garden carts and wheelbarrows to which they’d attached hula hoops with sheets over them, like genuine covered wagons. Everyone must have been gathering materials since kindergarten.