The name “lily” is frequently applied to flowers outside the genus Lilium, causing confusion. A true lily is botanically defined as a plant that grows from a scaly, underground bulb. Its flower structure features six petals (tepals) and six distinct stamens. These flowers are typically large, showy, and often trumpet-shaped, growing on a single, erect stem with leaves arranged in whorls or spirals. The common usage of “lily” for look-alike species is based on visual resemblance, despite the plants belonging to different families and possessing distinct botanical structures.
Daylilies: The Most Common Confusion
The daylily (Hemerocallis) is the most frequent source of mistaken identity, though it is not a true lily. The primary structural difference lies beneath the soil: daylilies grow from tuberous or fleshy roots, not the scaly, true bulbs of Lilium. This root structure results in a distinctly different growth habit above ground.
Daylily foliage consists of long, flat, strap-shaped blades that emerge in clumps directly from the base of the plant. True lilies, in contrast, feature leaves scattered or whorled along a single, unbranched flower stem. The flower’s lifespan is also different, as a single daylily bloom lasts for only one day before fading, which is the origin of its common name. True lily flowers remain open for a week or longer, making them a popular cut flower.
Flowers Defined by a Single Spathe
Another group of lily look-alikes is defined by a unique floral structure called a spathe and spadix, which separates them from Lilium. The “flower” is not composed of six petals, but rather a specialized, often colored, leaf-like bract called the spathe. This spathe wraps around a central spike, the spadix, where the plant’s actual flowers are clustered.
The Calla Lily (Zantedeschia) exhibits this structure with a large, funnel-shaped spathe that visually mimics a trumpet lily. Calla Lilies grow from a rhizome, which is an underground stem, not a true bulb. Similarly, the Peace Lily (Spathiphyllum) is an indoor houseplant known for its striking white spathe that cradles a pale yellow or white spadix. Both Zantedeschia and Spathiphyllum are part of the Araceae family, which is botanically distant from the true lily family, Liliaceae.
Peruvian Lilies and Other Spotted Varieties
The Peruvian Lily, or Alstroemeria, is frequently utilized in floral arrangements due to its resemblance to a smaller, delicate lily. This plant grows from tuberous roots and produces a cluster of funnel-shaped blooms atop its stems. While it features six tepals, the flowers are typically marked by distinct spotting, streaks, or darker “whiskers” on the inner petals.
A distinguishing feature of Alstroemeria foliage is that its lance-shaped leaves twist 180 degrees as they grow from the stem, a process called resupination. This causes the underside of the leaf to face upward. Peruvian Lilies are known for their vibrant colors, including tones of pink, orange, white, and yellow, and they possess a long vase life, sometimes lasting up to two weeks as a cut flower.