Plant Families of the Midwest

The Morton Arboretum's Naturalist Certificate Program
Plant Families of the Midwest - Winter 2001
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*Lilium* flower
Liliaceae Lilium Lily Calyx: 3 free sepals Corolla: 3 free petals Androecium: 6 free stamens Hypogenous Gynoecium: 1 pistil 1 stigma and style 1 Ovary with 3 chambers which means that there are 3 joined carpels - syncarpous no accessory flower parts

The perianth is interpreted to be 3 Sepals and 3 Petals which are identical in appearance. Often the term Tepal is used when you can't tell if they are sepals or petals. Note that their are two sets of 3; one set inside the other. The outside set would be the sepals, the inside set the petals. The androecium has two sets of stamens (3 + 3 = 6). Notice the orange pollen produced by the anthers. The gynoecium shows one pistil with a stigma, style, and ovary. The ovary is divided into 3 chambers (locules). You can also see the 3 lobes of the ovary from the outside and the 3 lobes of the stigma. So this is syncarpous - made of 3 fused carpels. There are leaves on the stem below the flower but no bracts.

There are two different ways that books will refer to the ovary position in relation to the other flower parts. In the lily flower, if you look from the viewpoint that the perianth and androecium are attached BELOW the ovary you would say the flower is hypogynous. If you look at it from the opposite perspective of how the ovary is positioned ABOVE the perianth and androecium you would say the ovary is superior. An inferior ovary (below the other parts) is found in flowers that are epigynous (perianth and stamens attached above ovary). Needless to say this is often confusing. Superior / inferior are the older terms.

Liliaceae are members of Class Liliopsida which contains the group of plants commonly named the Monocotyledons. The monocots typically have flower parts in threes (3 merous). We see this in the lily: 3 sepals, 3 petals, 3 + 3 stamens, 3 carpels. Dicots have flower parts mostly in multiples of 4 or 5, sometimes 2.