Lilies are recognizable and widely cultivated flowering plants. Although the name “lily” is frequently used for many different blooms, botanically it refers to a specific group of plants. Distinguishing between a true lily and a “false lily” requires understanding the unique physical characteristics that define its genus. This distinction impacts gardening techniques and pet safety.
The Defining Characteristics of True Lilies
True lilies belong exclusively to the plant genus Lilium, comprising about 100 species native to the Northern Hemisphere. These plants are characterized by a specific underground storage organ known as a scaly bulb. This bulb consists of fleshy, overlapping scales that lack the papery outer covering, or tunic, found on bulbs like tulips or daffodils. The loose scales of a true lily bulb are easily separated, which serves as a natural method of propagation.
The flower structure of all Lilium species displays parts in multiples of three. Each flower features six prominent segments called tepals, which are technically three petals and three sepals that look nearly identical. These tepals can be highly recurved, forming the classic “Turk’s cap” shape, or they can be fused at the base to create a trumpet or funnel shape. The stem is lined with linear or lance-shaped leaves arranged either alternately or in distinct whorls along the entire length of the stalk.
Categorization of Lilium Hybrids
Horticulturalists classify true lilies into nine divisions based on the species characteristics. Three popular groups are the Asiatic, Oriental, and Trumpet hybrids, each offering a distinct aesthetic and growth habit. Asiatic hybrids are often the first to bloom in early summer and are valued for their hardiness and vibrant colors, including oranges, reds, and yellows. These lilies typically feature medium-sized flowers that face upward or outward and are generally unscented.
Oriental hybrids represent a contrast, blooming later in the season during mid to late summer. They are distinguished by their large flowers, which can measure 6 to 8 inches across, and their intense, sweet fragrance. The color palette is usually restricted to whites, pinks, and reds, often with distinctive spots or stripes on the tepals.
Trumpet or Aurelian hybrids are known for their towering stature, frequently reaching heights of five to six feet. They feature long, waxy, trumpet-shaped flowers. These mid-summer bloomers emit a heavy, sweet fragrance, particularly in the evening, and are commonly found in shades of white, gold, and apricot.
Common Misidentified “Lilies”
Many popular garden and house plants are commonly called “lilies” despite having no botanical relationship to the Lilium genus. Daylilies (Hemerocallis) are frequently misidentified. They grow from tuberous roots rather than a scaly bulb, and their strap-like leaves emerge directly from a crown at the soil line, not along a central stem. The term “daylily” is apt because each flower bloom lasts for only a single day.
Calla Lilies (Zantedeschia) and Peace Lilies (Spathiphyllum) belong to the Araceae family. They do not grow from a bulb, instead producing from a rhizome in the case of the Calla Lily. Their structural difference lies in their inflorescence, which is not a flower with six separate tepals. What appears to be the flower is actually a spathe, a modified leaf, that surrounds a central spike of tiny true flowers called a spadix.
Water Lilies (Nymphaeaceae) are another non-related group. They are distinguished by their aquatic habitat and their growth from submerged rhizomes rather than a terrestrial bulb.
Toxicity and Safety
The distinction between true and false lilies is important regarding household safety, especially for cat owners. True lilies (Lilium species) and Daylilies (Hemerocallis species) contain an unknown, water-soluble toxin that is highly nephrotoxic, severely damaging the kidneys of cats. Ingestion of even a small amount of plant material, including leaves, petals, stems, pollen, or water from a vase, is considered a life-threatening veterinary emergency.
Initial symptoms of poisoning can appear within one to three hours, commonly presenting as vomiting, drooling, and lethargy. If left untreated, this progresses to acute kidney failure within 36 to 72 hours, resulting in dehydration and the cessation of urine production. Immediate veterinary intervention, often involving induced vomiting and intensive intravenous fluid therapy, is necessary to prevent fatal kidney damage.
In contrast, Calla and Peace Lilies are considered less dangerous. They contain insoluble calcium oxalate crystals, which cause immediate but temporary irritation to the mouth and throat, but do not cause kidney failure.