One of the best things about midsummer bloom in the garden is day lilies, and there are many amazing color choices and flower forms.  For an additional gardening information source for day lilies, click the link to The American Hemerocallis Society,  http://www.daylilies.org.  For a diagram of the parts of the day lily, click the link http://www.daylilies.org/ahs_dictionary/ImageMap.html.

Color Patterns

Bicolor - the petals and sepals are different colors.

Bitone - the petals and sepals differ in shade or intensity of the same basic color.

Blend - the flower is a blend of two or more colors.

Dotted, Flecked, Flaked, Speckled, or Stippled - colors are clumped into larger pools.

Dusted - color appears to be finely misted onto the surface.

Diamond dusted - the flower has a sparkling or glistening appearance as if sprinkled with gold, silver, or tiny dimonds.

Edged or Picoteed - the edges of the flower segments are either lighter or darker than the segment color.

Eyed, Eyezoned or Banded - the flower has an area of different or darker color (called a zone) between the throat and the tips of the flower.  It is an eye if the zone occurs on both the petals and the sepals.  It is a band if the zone occurs only on the petals.  It is a halo if the zone is faint or only lightly visible.  It is a watermark if the zone is a lighter shade than the rest of the flower.

Midrib - the center vein of each flower segment; it may be different in color from the rest of the segment.

Polychrome - the flower segments have an intermingling of three or more colors.

Self - the flower is the same color throughout; the stamens and throat may be different.

Tipped - the segment tips, or just the petal tips, are a different or contrasting color from the body of the segment.

Flower Form

Circular - the flower appears round; segments often overlap, giving a full appearance.

Double - this form has more than six segments; the extra segments may appear as a tuft in the middle of the flower if they may appear as two blooms in one.

Flaring - the segments arch out from the throat; the flaring side view most often accompanies the triangular front view.

Flat - flowers are flat except the throat, which is concave.

Recurved - the flower flares, but the ends roll or tuck under.

Ruffled - there are ruffles along the flower edges.

Spider - flowers with very narrow petals and a spider-like form; also referred to as an informal form.

Star - the flower shape looks like a three-pointed or six-pointed star.

Triangular - when viewed from the front of the bloom, the flower segments form a triangle.

Trumpet - segments rise from the throat in an upward pattern rather than the usual outward pattern; the flower form resembles a true lily.

Flower Size

Miniature - flowers less than 3 inches in diameter.

Small - flowers from 3 inches up to 4 inches in diameter.

Large - flowers 4 inches and over in diameter.

Height

Low - the scapes are from 6 to 24 inches high.

Medium - the scapes are from 24 to 36 inches high.

Tall - the scapes are more than 36 inches high.

Bloom Time

Nocturnal - day lilies open late in the afternoon and remain open all night.

Diurnal - day lilies only open during the day.

Extended - day lily blooms remain open at least 16 hours; both diurnals and nocturnals may be extended bloomers.

Extra Early (EE) - varies from March to June depending on your zone.

Early (E) - three to five weeks prior to the mass of bloom at midseason.

Early Midseason (EM) - this ranges from May to July depending on your zone.

Late Midseason (LM) - one to three weeks after the height or peak of bloom in your garden.

Late (L) - four to six weeks after the peak of the season.

Very Late (VL) - these day lilies are the last to bloom in late summer or early fall.

Rebloomer (RE) - these day lilies bloom more than once during a single season.

Everbloomer - these day lilies bloom repeatedly through the summer and may have very little or no time between flushes of bloom.  This is a relatively new term for day lilies and the goal of many hybridizers.  Stella De Oro is the top everbloomer followed by Happy Returns and Rosy Returns.

Plant Types

Dormant - the leaves of these day lilies die completely back as winter approaches.

Evergreen - these day lilies retain their leaves throughout the year; in mild winter climates, the leaves remain green all winter.

Semi-evergreen - this is an intermediate classification.

In general, evergreen types will do better in hot climates with very mild winters, and dormant types prefer colder areas.

Chromosomes

Diploid - have 22 chromosomes.  Day lilies are considered by some to be more graceful in form.  Spider and double day lilies are more commonly diploid.  Although diploid flowers may be smaller, they are also more numerous. 

Tetraploid - have 44 chromosomes.  Have larger flowers, colors are often more intense, and scapes tend to be sturdier and stronger.