Heartland Peony Society Glossary

Heartland Peony Society Index of Botanical and Peony Terms

Biternate: A leaf divided into 3 main divisions, each of which is divided into 3 leaflets.

Carpel: The female portion of a flower containing: 1) an ovary, holding one or more egg cells. 2) style and 3) stigma which is at the tip of the style. during pollination, it is the receptor for pollen.

Chimera: An organism composed of two genetically different types of tissue. Both types of tissues have originated from the same zygote, and the difference is often due to mutation during ordinary cell division.

Cultivar: A specific cultured variety of plant. A cultivated plant variety or cultural selection. An international term denoting any cultivated plant that is clearly distinguishable from others by one or more characteristics and which when reproduced retains those characteristics. In the USA "variety" is considered to be comparable to cultivar.

Deciduous: Describes a plant whose leaves fall off seasonally, or a leaf which falls off seasonally. Most deciduous plants shed their leaves in autumn at the end of the growing season. Typically all tree peonies are deciduous in nature.

Epigeal: A seed is described as epigeal when the cotyledons of the germinating seed expand, throw off the seed shell and become photosynthetic above the ground. (Opposite = Hypogeal).

Family: The taxonomic group of plants or animals consisting of distinct genera.

Genus: (Pl. Genera): The smallest natural taxonomic group of plants or animals consisting of distinct species.

Graft: 1) Propagation of plant by transfering part of one plant to part of another resulting in a new plant. In tree peonies a desired cultivar is grafted onto a root to speed up propagation.
2) The result of the above propagation.

Hemicryptophyte: Perennial plant whose buds are located at the level of the ground during the periods of vegetative rest (winter, dryness): Rather than other forms such as phanérophyte, chaméphyte, cryptophyte, geophytes, helophytes, epiphytes, and hydrophytes. Most species of herbaceous peonies are considered to be hemicryptophytes with their buds wintering at or near the ground surface.

Herbaceous: Plants which die to the ground each winter. The plants loose all growth which is above ground and all growth for the next year emerges from below the ground surface.

Hilum: (Pl. Hila)The mark or scar on a seed produced when it is removed from the pod.

Hybrid: Originally a cross between two distinct species, but now a combination of any two genetic lines. Common peony hybrids involve up to four species, but some 'hybrids' include selections within a single species.

Hypogeal: A seed is hypogeal when the cotyledons of the seed remain inside the seed shell, remain below ground and are non-photosynthetic. The converse, a seed is epigeal when the cotyledons expand and cast off the seed shell above the ground and become photosynthetic.

Leaf Spot: A disease of fungal or bacterial origin that produces discolored spots

Ovary: The part of the carpel, usually the enlarged base, which contains the ovules which eventually becomes the seed.

Pinnate: Bearing leaflets on each side of a central stalk. The arrangement of leaflets (in a compound leaf) on opposite sides of a common axis.

Pollen: The male element in flowering plants which carry the DNA of plants during fertilization of flowers. Pollen appears as a fine dust produced by the anthers.

Rootstock: A portion of root to which scion is grafted to propagate a tree peony.

Scion: The selected part of the plant which is used in a graft. In the case of tree peonies, it is a stem segment from the current year's growth that is taken near the end of the growing season.

Species: 1) A population of plants that share similar characteristics and interbreed. A population will show some natural variation, but retain basic characteristic both in external features and genetic make-up.
2) The basic taxonomic level. Species names are in Latin or have been Latinized. The species name is a binomial consisting of genus and species, consisting of two words such as Paeonia officinalis or Paeonia rockii. All peony species are members of the genus Paeonia.

Summer Deciduous: Some peonies have the habit of becoming dormant in mid-summer. Particularly this occurs if subjected to stress such as high temperatures and drought. For herbaceous peonies the term means the plant looses its leaves as well as above ground stems before the end of the summer.