tokens: Cultivars that descend from Geheimrat Dr. Oldenburg include : Alkmene ( Geheimrat Dr. Oldenburg × Cox 's Orange Pippin ) ; Apollo ( Cox 's Orange Pippin × Geheimrat Dr. Oldenburg ) ; Clivia ( Geheimrat Dr. Oldenburg × Cox 's Orange Pippin ) ; ; Elektra ( Cox 's Orange Pippin x Geheimrat Doktor Oldenburg ) ; Roba ( Geheimrat Dr. Oldenburg x unknown ) ; and possibly Dukat ( Geheimrat Dr. Oldenburg × Cox 's Orange Pippin ) .