Euphorbia flanaganii f. cristata is a succulent plant with a swollen underground stem. Euphorbia flanaganii
has two cristate forms. One with a cristate central shoot and normal cylindrical lateral shoots developed on it and another with cristate lateral shoots only, without main shoot. The form with lateral shoots type cristation is very common in cultivation. It looks very different from the species and forms a thin flattened crowded cluster and develops, in time, a large cushion-like mass, up to 6 inches (15 cm) tall and up to 12 inches (30 cm) wide, which resemble a wavy emerald-green coral. The form with caudex cristation forms a snaky, fan-shaped ridge with normal cylindrical lateral shoots developed on it. It is quite rare and very different from the cristation involving a lateral shoot.