Abstract Factory and Inheritance Kotlin

I'm trying to wrap my head around Kotlin design patterns. I've created my Abstract Factory, using the Kotlin reference as a starting point

interface Plant

class OrangePlant : Plant

class ApplePlant : Plant

abstract class PlantFactory {

    abstract fun makePlant(): Plant

    companion object {
        inline fun <reified T : Plant> createFactory(): PlantFactory =
                when (T::class) {
                    OrangePlant::class -> OrangeFactory()
                    ApplePlant::class -> AppleFactory()
                    else -> throw IllegalArgumentException()
                }
    }
}

class AppleFactory : PlantFactory() {
    override fun makePlant(): Plant = ApplePlant()
}

class OrangeFactory : PlantFactory() {
    override fun makePlant(): Plant = OrangePlant()

I'd like all factory instances to inherit from my existing Abstract class Foo. How would I do it? Like this? What am I missing? Or have I lost my mind and haven't realised it?

interface Plant

class OrangePlant : Plant

class ApplePlant : Plant

abstract class PlantFactory {
    abstract fun makePlant(foo: Foo): Plant

    companion object {
        inline fun <reified T : Plant> createFactory(): PlantFactory = when (T::class) {
            OrangePlant::class -> OrangeFactory()
            ApplePlant::class  -> AppleFactory()
            else               -> throw IllegalArgumentException()
        }
    }
}

class AppleFactory : PlantFactory() {
    override fun makePlant(): Plant = ApplePlant()
}

class OrangeFactory : PlantFactory() {
    override fun makePlant(): Plant = OrangePlant()
}

Or should I be looking to add into the companion object?