Plants evolved on land from green algae that likely lived in waters that dried out. Survival on land meant that plants had to adapt to their environment, such as getting nutrients and reproducing without water.
Although many flowers are called lilies, true lilies (Lilium sp.) grow from bulbs, which are fleshy underground storage structures that store nutrients for the plant. An Easter lily is a true lily, a daylily is not. Bulbs themselves are plant adaptations, notes the University of Florida IFAS Extension. Lilies developed them in time to survive long periods of environmental stress, such as cold or drought.
Some plants adapted by developing odd characteristics. Rafflesia sp. are not true lilies but are commonly called corpse lilies because they produce a scent like a rotting animal carcase. The bad scent attracts carrion flies for pollination.
Also not true lilies, water lilies (Nymphaea sp.) have leaves floating flat on the water's surface. Unlike flowers living on land, water lilies have most of their stomata, microscopic pores allowing the passage of carbon dioxide, oxygen and water during photosynthesis, on the upper side of their leaves, instead of the underside.
Plants typically have showy flowers luring pollinators. Calla lilies (Zantedeschia sp.), again, not true lilies, have what appear to be trumpet-like petals surrounding a spike. These petals are technically modified leaves, called spathes. The spike, or spadix, is the real flower.