Alstroemeria, commonly known as the Peruvian Lily or Lily of the Incas, is a favorite in floral arrangements globally due to its vibrant colors and exceptional longevity as a cut flower. Its common names, which include “lily,” frequently lead to confusion about its actual scientific relationship to true lilies. Given the significant differences in plant care and, more importantly, household safety, it is helpful to establish the precise botanical identity of this popular bloom.
Botanical Identity of Alstroemeria
Despite its popular designation, Alstroemeria is not a member of the family that contains true lilies. Scientific classification places all true lilies in the genus Lilium, which belongs to the family Liliaceae. Alstroemeria, however, is classified under its own distinct family, Alstroemeriaceae.
This taxonomic separation signifies that while both plant groups are monocots and share a distant evolutionary ancestor within the order Liliales, they represent different lineages. The two families diverged long ago, leading to distinct biological characteristics in their growth, structure, and chemical makeup. This difference in family is the definitive scientific answer to whether Alstroemeria is a lily.
Distinctive Growth Habits and Floral Structure
Physical characteristics of the Alstroemeria plant provide clear visual evidence for its separate classification from Lilium species. True lilies develop from a true bulb, which is a fleshy, layered structure containing an embryonic plant and food storage. In contrast, Alstroemeria grows from a cluster of tuberous roots or rhizomes, which are underground stems that spread horizontally to form new shoots. This root structure is a fundamental difference in their life cycles and propagation methods.
A striking and easily observable feature of Alstroemeria is the unique twist in its leaves, a characteristic known as resupination. The leaf blade twists 180 degrees at its base, or petiole, causing the surface that is botanically the underside to face upward toward the light. True lilies (Lilium species) possess flat, untwisted leaves that emerge directly from the stem.
The flower itself, while superficially lily-like, features six petal-like structures called tepals. The two inner tepals often display distinctive streaks, spots, or dark markings that serve as nectar guides for pollinators.
Differences in Toxicity and Handling
The most significant practical difference relates to their toxicity, especially in households with pets. True lilies (Lilium and Hemerocallis genera) are highly toxic to cats. Ingestion of any part of the plant, including the pollen or even the vase water, is capable of causing irreversible, acute kidney failure and is a life-threatening veterinary emergency.
The Peruvian Lily, conversely, does not cause this severe systemic damage. Alstroemeria contains a chemical compound called tulipalin A, which is a mild irritant. If a pet ingests the plant, it may result in mild gastrointestinal upset, including vomiting or diarrhea, but these symptoms are usually self-limiting.
For humans, tulipalin A is a common sensitizer known to cause contact dermatitis, particularly in florists. This condition, sometimes referred to as “tulip fingers,” causes fissuring, redness, and itching following direct contact with the plant’s sap. Sensitive individuals handling Alstroemeria should wear protective nitrile gloves, as the allergen can penetrate certain materials like vinyl.