Variation in corolla

• Apetalous – without petals; sometimes the petals are reduced into inconspicuous scales.
• Bilabiate – when the united corolla becomes two-lipped at the rim
• Campanulate – when the united corolla assumes the shape of a bell.
• Funnel-shaped or funnelform – when the corolla tube gradually expands upward like that of a funnel.
• Gamopetalous or sympetalous – when the sepals are united at their margins forming a corolla tube.
• Ligulate or strap-shaped – the base of a short tube opening out into an elongated, flat, strap-like appendage.
• Ligule – a flattened part of a ray corolla.
• Lip – these are projections in a two-lipped bilabiate corolla of an irregular flower.
• Papilionaceous – irregular flowers of family Fabaceae resemble that of a butterfly.
• Plicate – when the petals are folded in longitudinal plaits.
• Polypetalous or choripetalous – when the petals are distinct or free.
• Rotate or stellate – the petals are wheel-shaped, the lobes radiate from the base.
• Salvershape – the corolla tube is elongated and the short corolla limb spreads horizontally.
• Spur – a protruding structure of the corolla or calyx.
• Tubular – when the corolla tube is elongated, the size is almost uniform throughout the tube.
• Urceolate – when the corolla is shaped like an urn.