This site uses a lot of terms that may be unfamiliar. I hope the following explanations are useful.

AIS: American Iris Society

amphidiploid: a type of tetraploid in which two of the chromosome sets are of one type, and two are of another type. Amphidiploids are generally fertile.

aril: a type of iris native to Asia, related to the bearded irises. The name derives from the "aril" (conspicuous light-colored collar) on the seeds of these irises.

arillate: having an aril, hence any iris with an aril seed; includes both arils and arilbreds.

arilbred: a hybrid involving both bearded irises and aril irises.

arilbred dwarf (ABD): as used on this site, an arilbred less than 13 inches (33 cm) tall. Most are APT triploids from crossing SDBs with pure arils.

arilbred median (ABM): as used on this site, an arilbred iris of one-half aril content or less, between 13 and 22 (33 and 56 cm) inches tall. Most are APTT unbalanced tetraploids from crossing SDBs with C. G. White type arilbreds.

arilpum: a colloquial term for dwarf arilbreds derived solely from arils and Iris pumila.

ASI: Aril Society International

BIS: British Iris Society

border bearded (BB): median irises from 16 inches up to 27.5 inches (41 to 70 cm) tall, that do not have the delicate proportions of the MTBs or the early bloom season of the IBs. Most are 48-chromosome tetraploids (TTTT).

C. G. White type arilbred: amphidiploid (AATT) arilbreds, typified by those produced by C. G. White in the 1950s, but including all arilbreds that are members of this fertile family

chromosome: a structure inside the nucleus of a cell that carries some of the organism's genes. Each chromosome carries many genes. The chromosomes of different species vary in number, size, and shape.

clone: all plants derived from vegetative propagation (division) of a single individual.

colchicine: a poisonous substance used to double the number of chromosomes in the cells of plant, and hence convert a diploid into a tetraploid

cultivar: a "cultivated variety" ; iris cultivars are vegetatively propagated named clones.

diploid: an organism with two sets of chromosomes.

DIS: Dwarf Iris Society

fertile family: a group of irises that are fertile with each other and produce offspring that are also fertile with other members of the family.

gamete: a sex cell, either an ovule (female) or pollen grain (male) for flowering plants

homolog: two chromosomes are homologs (adj. homologous) if they are similar in shape and size and pair during cell division.

hybrid: an offspring of dissimilar parents, usually of different species or species ancestry.

intermediate bearded (IB): median bearded irises from 16 inches up to 27.5 inches (41 to 70 cm) tall, blooming before the tall beardeds.

Iris aphylla: a small bearded iris species from eastern Europe, a 48-chromosome tetraploid (TTTT). It is useful in breeding because of its small size and copious branching and bud count. It has been used by Hager, the Craigs, and others to produce tetraploid MTBs and other medians.

Iris balkana: a dwarf bearded iris species from the Balkans, now usually regarded as a synonymn of Iris reichenbachii. Most forms counted are tetraploid (TTTT).

Iris pumila: a dwarf bearded iris species from eastern Europe, a 32-chromosome tetraploid (PPPP). Crossed with TBs, it gave rise to the modern standard dwarfs, and indirectly to most IBs and MDBs as well.

Iris reichenbachii: a dwarf bearded iris species from the Balkans, which occurs in both diploid (TT) and tetraploid forms (TTTT). See Iris balkana.

Iris schachtii: a small, branched bearded iris species from Turkey. It is a TTTT tetraploid.

median: bearded iris from 8 inches to 27.5 inches (21 to 70 cm) tall. Includes SDB, IB, MTB, and BB classes.

miniature dwarf bearded (MDB): bearded irises up to 8 inches (20 cm) tall.

miniature tall bearded (MTB): median bearded irises from 16 inches up to 27.5 inches (41 to 70 cm) tall which have delicate blooms and slender stems.

MIS: Median Iris Society

oncocyclus: a type of aril iris native to the southern Caucasus, Turkey, Iran, Syria, Jordan, and Israel. Known for spectacular blooms, often globular in shape and intricately marked. All species are 20-chromosome diploids (AA).

oncogelia (OG): a pure aril hybrid of predominantly oncocyclus phenotype, typically more than 1/2 oncocyclus content.

ovules: the female gametes (sex cells) of a flowering plant. The ovules are located in the ovary at the base of the bloom, which becomes a seed pod upon successful pollination.

pollen: the male gametes (sex cells) of a flowering plant. The pollen is located on the anther at the end of the stamen.

Regelia: a type of aril iris native to Turkestan and Afghanistan. Of the commonly grown species, Ii. hoogiana and stolonifera are 44-chromosome tetraploids (AAAA), while I. korolkowii is a 22-chromosome diploid (AA).

regeliocyclus (RC): a pure aril hybrid of predominantly Regelia phenotype, typically 1/2 or less oncocyclus content.

seedling: an iris grown from seed, often used in the specific sense of an offspring of a planned cross that has not been given a cultivar name.

SIGNA: Species Iris Group of North America

species: a naturally occuring range of populations, identified by botanists as distinct from other species. See Species Nomeclature: Naming the Wild Irises.

standard dwarf bearded (SDB): bearded irises from 8 inches up to 16 inches (21 to 40 cm) tall. Despite the name, SDBs are considered medians, not dwarfs. Most are amphidiploids from TB/pumila breeding (PPTT).

tall bearded (TB): bearded irises over 27 inches (70 cm) tall. Most are 48-chromosome tetraploids (TTTT).

tetraploid: an organism with four sets of chromosomes.

triploid: an organism with three sets of chromosomes.

unbalanced tetraploid: a type of tetraploid in which the chromosome sets are of different types, but which is not an amphidiploid. Unbalanced tetraploids have limited or no fertility.

unreduced gamete: a gamete (ovule or pollen grain) which by chance contains the plant's full complement of chromosomes, rather than only half as normal gametes do.

Tom Waters

September 2010

updated May 2018

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Unless otherwise noted, all text and illustrations copyright Tom Waters and all photographs copyright Tom or Karen Waters. Please do not reproduce without permission.