Daylily
Hemerocallis is a genus of herbaceous, perennial, and rhizomatous plants belonging to the Asphodelaceae family that contains about fifteen species native to Asia. «Day lily» is the most frequent common name used to designate the Hemerocallis species and the cultivars obtained from them. This common name alludes to the fact that the flowers of most species of Hemerocallis open their petals at dawn and wither at dusk, so that each flower does not last more than a day. However, once it withers, each flower is replaced by another on the same stem the next day, so the flowering period of the same plant is very long. Some species open their flowers at night, which wither at dawn the next day.
Distribution
The genus Hemerocallis is native to temperate regions of Asia, particularly Japan, Siberia, Korea and China. Their large and showy flowers have made them popular throughout the world and, through their cultivation, several of the species of the genus have spread, and even become naturalized in many countries in Europe and America.
Etymology and common names
The name Hemerocallis comes from the Greek words for day and beauty, reflecting the fact that individual flowers last only one day. The common name in other languages is: "Taglilie" (German), "hémérocalle" (French) and "daylily" (English). In Spanish, in addition to being known as "day lily", it is also called "japonesa lily", "morning lily" or, "Saint John lily", "yellow lily", "Turkish lily" or, simply, "hemerocalis".
Description
They are herbaceous, perennial, rhizomatous plants with thickened roots. The leaves are linear-lanceolate and sharp. The flowers are large and showy, actinomorphic and hermaphrodite, arranged in pauciflorous inflorescences (2 to 5 flowers), branched, at the apex of a long scape. The perigonium is funnel-shaped or bell-shaped and is made up of 6 tepals arranged in two whorls, which are united at their base to form a short tube, the length of which is highly variable among the different species of the genus. The androecium is made up of 6 stamens, also arranged in two whorls. The filaments are threadlike and curved. The anthers are linear-oblong, dorsifixed, bi-locular and with longitudinal dehiscence. The ovary is inferior, tricarpellate and trilocular, with numerous ovules per locule which are arranged in two rows. The placentation is axillary. The style is threadlike and long. The stigma is small and slightly thickened, capitate or 3-lobed.
The fruit is a trivalve capsule with rounded angles and loculicidal dehiscence. In many cases the fruits do not form or develop because the plant is sterile. The seeds are round, black and shiny. The basic chromosome number is x=11, with diploid and triploid species.
Uses
Ornamental
Plants of this genus are widely used in gardening, especially in landscaping, to cover relatively large surfaces with great color and very low maintenance due to the fact that they are rustic species. They are not frequently used in flower arrangements due to the short life span of each flower, although once a flower withers they continue to open new flowers on the same cut stem for several days.
Food
The flowers of some species are edible and, in fact, daylilies are cultivated for this purpose in some Asian countries, such as China. The flowers are sold in Asian markets both fresh and dried, calling them golden needles. They are used in soups (hot and sour soup) and moo shu pork. Leaf buds, young leaves, and tubercles of some (but not all) species are edible.
The tepals of the day lily are delicious when eaten directly after flowering and are a very good source of iron and vitamin A. They range in flavor from spicy a fruity like peach and its sweetness is due to the presence of nectar at the base of the perigonium.
It must be absolutely certain that the daylily or lily of the day that is intended to be consumed is not a true lily (lilies or lilies belong to the genus Lilium, family Liliaceae), as the flowers of this last species can be very toxic.
Medical
Various species of Hemerocallis have been used for medicinal purposes for centuries in the Far East. In particular, the stems and roots have been used as pain relievers. A medical book compiled in the Zhou dynasty (ca. 1059 BC) explained that the roots of Hemerocallis were "refreshing and not poisonous" and advised its use as a diuretic and to treat incontinence. The juice extracted from the fleshy roots, as well as the boiled young stems, were supplied to treat patients with cirrhosis. The leaves of the daylily have also been used in traditional Chinese medicine for the treatment of inflammation.
In addition to the rich experience of using these plants over the centuries provided by traditional medicine, modern methods of analysis of compounds have allowed us to glimpse that the genus Hemerocallis presents an innumerable number of molecules with interesting pharmacological properties. Thus, through the study of extracts of fresh leaves of Hemerocallis fulva several compounds have been isolated, such as roseosides, flomurosides, lariciresinol and several derivatives of quercetin, all of them with strong antioxidant properties. Other A new antioxidant called Stelladerol (a naphthalene glycoside) was isolated and characterized from the leaves of "Stella d'Oro", a small-flowered daylily cultivar. In addition to these compounds with antioxidant activity, Several new anthraquinones have also been isolated from the flowers and roots of daylily, which were named "kwanzoquinones" since they were found in the variety "Kwanzo" of Hemerocallis fulva. It has been verified that these molecules exhibit antitumor effects "in vitro" against 4 human cell lines and the anti-proliferative activity and cytotoxicity of such compounds have also been documented.
Hemerocallis species
List of species
The species of the genus, arranged alphabetically, are:
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Brief description of some species
The following describes some of the species of the genus that have had a great participation in the creation and development of modern daylily cultivars. Many of these species, moreover, are still cultivated in many parts of the world, despite the fact that their use is continually being replaced by that of modern hybrids.
- Hemerocallis fulva
Species with reddish-orange flowers, 7-12 cm long, gathered in 6-10-floral panicles at the end of a long bracteate scape 6-8 dm high.
The species exhibits some variants in the shape and color of the flowers and in the growth habit. Hemerocallis fulva var. Kwanso and Hemerocallis fulva var. Flore Pleno have double flowers, in which the stamens become tepals. Hemerocallis fulva var. rosea has pinkish-red flowers. Hemerocallis fulva var. littorea displays an evergreen growth habit.
The species is diploid (2n=22), however, the varieties "Kwanso" and "Europe" They are highly sterile triploid clones (2n=33) that multiply asexually through their rhizomes.
This species has contributed several characters to today's daylily hybrids, including recurved and sinuous-margined tepals, lighter midrib on tepals, and an intermediate to long perigonial tube. Some varieties of this species show up to 100 flowers per scape.
- Hemerocallis lilioasphodelus
The flowers are lightly scented, lemon yellow, up to 7-8 cm long and 7.5-10 cm in diameter. The tepals are united at their base, forming a perigonial tube 2.5 cm long. The flowers are gathered in 5-9-floral paniculate inflorescences, at the end of a long bracteate scape up to 1 m high, branched in its upper portion.
It is a species that is not very sensitive to excess water in the soil. In the development of modern daylily cultivars, this species has contributed with its earliness (it is one of the fastest flowering species), with the fragrance of its flowers and with a long flowering period.
- Hemerocallis minor
It is a herbaceous, perennial, deciduous, rhizomatous plant with thickened roots. The leaves are graminiform, 3-5 cm long by 6 mm wide at most. The flowers are yellow, lightly scented, up to 10 cm long, 5-6 cm wide, funnel-shaped, with a brownish tinge on the outside, arranged in briefly branched scapes 25-30 cm high. This species has contributed to the development of modern low-growing, fragrant hybrids.
Cultivated Daylily
The daylily plants cultivated today are, almost entirely, complex hybrids resulting from the crossing between several species of the genus that have been carried out since the beginning of the s. xx. The botanical nomenclature of the cultivated daylily is, therefore, extremely complicated since none of the current cultivars, those with great diversity in flower sizes, colors and shapes as well as flowering times, can be identified by the name of none. of the wild taxa of the genus. For this reason, almost all cultivars are named with the genus name followed by the cultivar name in quotation marks.
History of cultivation in the West
The different species of Hemerocallis were used for more than 4000 years by the peoples of the Far East as food, medicine or as ornamental plants. The first specimens of the genus were introduced to Europe by explorers traveling to the East around the middle of the 16th century. For centuries they were multiplied and cultivated throughout Europe as ornamental plants, maintaining the characteristics of each species.
Origin of current varieties
The first breeding program for daylily was established in the mid-1850s by George Yeld and Amos Perry in England. However, the real revolution in the genetics of this crop occurred around 1920, when Ardow Burdette Stout began his work on hybridization and improvement of daylily while serving as director of the New York Botanical Garden. The first variety of his, & # 34; Mikado & # 34; was registered in 1929 and marketed by the company "Farr Nursery" from Pennsylvania. Stout was a pioneer in the study and use of different species of daylily to create new cultivars.
Since then, and thanks to the distribution of the cultivars created by Stout and the dissemination of his scientific work, many geneticists and breeders in the United States and England made extensive modifications to the original species of Hemerocallis. For example, in the wild species of the genus the only colors available are yellow, orange, and brick red. Today there are almost white, yellow, orange, pink, bright red, purple, scarlet, pastel shades, and some are even almost blue cultivars. Furthermore, many of the possible combinations of those colors have been created. In fact, the number of cultivars of Hemerocallis in the world exceeds 60,000. All of them have been developed through a complicated history of interspecific crossings, selection and induction of polyploidy.
Diploids and tetraploids
The vast majority of Hemerocallis species are diploid, that is, in the nuclei of their somatic cells they have two sets of chromosomes that, in total, add up to 22 chromosomes (in genetics, the expression to say the same thing, "2n=2x=22 chromosomes"). Some clones or wild varieties of the genus are triploid (ie, 2n=3x=33 chromosomes). These triploid clones are highly sterile since in the cell divisions that give rise to the spores (meiosis) the 3 sets of chromosomes cannot be equally distributed among the daughter cells, which is why highly unbalanced cells are formed in their chromosomal endowment. those that end up degenerating. Due to this degeneration of the spores, neither are gametophytes (embryonic sacs or pollen grains) or gametes (oospheres or generative nuclei) formed and, for this reason, the plants are sterile.
During the history of breeding daylilies, it was possible to obtain tetraploid plants by treating normal plants with a chemical agent: colchicine. Colchicine is an alkaloid widely used in genetics to precisely obtain cells, tissues and plants with twice the chromosome endowment of the original plant. These tetraploids have 4 basic sets of chromosomes in their somatic cell nuclei (they are 2n=4x=44). Meiosis in these plants is quite normal because the chromosomes can be distributed equally between the daughter cells and, therefore, they are fertile.
These tetraploid plants have a number of extremely interesting characteristics for an ornamental plant like daylily. In general, the size of all the organs of the plant (including the flowers) is greater than that of the original diploids. The scapes that support the flowers tend to be thicker and more rigid. The colors of the flowers are more intense and, due to the possibility of complementing several different genes that govern the color of the flowers, new types, shades or combinations of color are achieved that would be impossible to obtain in diploid plants. Plant vigor is even greater in tetraploids than in the diploids that gave rise to it.
Experimental work to create tetraploid daylily began in 1940. In 1947, the flowering of the first tetraploid daylily plant was reported, a success that was continued in the following years by different research groups. By 1949, the first tetraploid cultivar named "Tetra Starzynski" followed two years later by two other cultivars, "Tetra Apricot" and "Tetra Peach". All three clones were developed by Dr. Hamilton Traub, who worked for the United States Department of Agriculture. However, the most intense work on genetic improvement of tetraploid daylilies only began towards the end of the 1960s. In the following years, improvement coexisted at both the diploid and tetraploid levels, which determined the creation and registration of thousands of cultivars of both. ploidy levels. At present, however, the larger breeding programs have definitely favored tetraploid cultivars.
The color of daylily flowers
Modern daylily cultivars exhibit great color diversity, especially when considering the narrow range of shades of the wild species from which they arose. Below is a description of the most frequent types of colors, both in the distal part of the tepals, in the throat and in the central rib and, finally, the color combinations that can be found.
The basic color
The color in the most distal part of the tepals is considered the basic color of the flower of a cultivar, which can be:
- yellow: all the shades of yellow, from the lightest lemon, passing through the bright yellow and the golden to the intense orange.
- red: various tones of scarlet, carmine, red tomato, red and red almost black shade.
- rose: from light pink to intense pink.
- purple: from a light lavender, passing through the lilac to the violet.
A blue-lavanda cultivar. - others, like melon, cream to almost white.
The color of the throat
The central area of a daylily flower is called the throat. In most cultivars the color of the throat differs from the basic color. Some of the most frequent colors are greenish, yellow, gold, orange, peach or melon.
The color of the stamens
Like the throat, the stamens can be of a different color than the basal and throat stamens. They are usually pale yellow or greenish.
The color of the central rib
The central rib that runs longitudinally through each tepal is called the central rib. The color of this central rib can be the same as the basic color or it can be different.
Color patterns
Modern cultivars exhibit complex color patterns that are unknown in the wild species from which they are derived. Some of those patterns are:
- "self": is the simplest pattern, in which all teapals have the same basic color.
A self farming. - Mix: Tepalos are a mixture of two or more colors.
- Bitono: external teapals differ with respect to inmates in the intensity or tone of the same basic color.
- Bicolor: external and internal teapals are of different colors.
A "bicolor" cultivation. - Banding: the flower displays a darker area between the throat and the tip of the teapals.
Daring Deception a cultivar "banded".
Flower Shapes
The current cultivars of daylily present a great diversity of forms that have been selected over the decades. Thus, a flower seen from the front can be circular, triangular or star-shaped. The edges of the tepals can be smooth or with many variants of waves. When viewed from the side, the flowers may be flat, recurved, or trumpet-shaped. To complete all this diversity, there are double daylilies, in which there are more than 6 tepals in each flower; and daylily "spider", in which the tepals are at least four times as long as they are wide. Another type of daylily, the newest and least frequent, is called "politépalo". The characteristic is that its flowers are not trimerous, like those of any other daylily, but 4-merous, that is, instead of having 6 tepals, it has 8 and exhibits 8 stamens instead of the typical 6. This class of daylilies can be confused with those with double flowers, however, in the "doubles" what is altered is the number of cycles of the flower, on the other hand, in the polytepals the number of floral parts per cycle is modified.
Foliage characteristics
Foliage color of different hybrid cultivars of daylily ranges from bluish-green to yellowish-green and everything in between. The size of the leaves is also very heterogeneous. It can range from grass-like leaf size and general appearance to corn leaf width and texture. The leaves can be erect or pendulous and the length can vary between 2 and 9 dm. The foliage behavior of daylilies during the cold winter months is known as 'foliage habit', which, for purposes of describing the different cultivars, can be categorized as evergreen, semi-evergreen, and deciduous.
- perennifolios. The hemerocalis of this category retain their foliage throughout the year. They do not produce resting buds but continually produce new leaves, unless the temperature is so low that growth stops. In mild climates, the leaves of this type of hemerocalis remain green throughout the winter. In colder areas, low temperatures burn the foliage but the crown survives. From the crown, the outbreak will begin once the temperature increases. In severe winter zones it is advisable to cover the crowns of the hemerocalis with dry grass to protect them from excessive cold.
- caducos. The deciduous hemerocalis completely lose their leaves when during the winter. As the autumn progresses, these hemerocalis stop their growth, form sleeping buds in the crown, and the foliage becomes yellow and gradually dying. In spring they vigorously restart their growth from these buds.
- semi-perennifolios: it is used to describe any behavior of foliage that is intermediate between the previous two.
Cultivar cold hardiness has no relationship to foliage habit. Thus, there are deciduous foliage cultivars as tolerant or as sensitive to low temperatures as the evergreen cultivars.
Small-flowered daylilies
Small-flowered cultivars are those that have flowers with a diameter of 76 to 114 mm (the original definition is in inches, 3 to 4.5 inches, for that reason they may miss the decimal places when using the system decimal metric in the definition). If the cultivar presents flowers with a diameter less than 76 mm, it is said to belong to the "miniature" category.
Both small-flowered and miniature cultivars have been developed from crosses between the small-flowered species Hemerocallis minor, Hemerocallis citrina and Hemerocallis middendorffii . Small-flowered or miniature daylilies are sought after by many gardeners to grow on patios, small gardens, and balconies where color is desired without too much care or maintenance.
Cultivation and multiplication
Many species of Hemerocallis and the hundreds of hybrid cultivars available are used in gardens and landscaping as they provide color and contrast in beds of perennials when grown in groups. In large parks, they are also effective in dealing with erosion by cultivating them on slopes and in keeping large spaces free of weeds.
Flowering of the different varieties of daylily occurs from mid-spring, and for each plant, the flowering period lasts several weeks. Because different hybrid cultivars start blooming at different times, growing multiple varieties will give you plenty of blooms from spring through fall. Daylily foliage is also prized for its elegance, which is why these plants provide color and texture in perennial beds with their leaves.
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It is an easy plant to grow in any well-drained soil and in a place with full sun. It is tolerant of poor soils, excessively hot summers, and lack of moisture. However, they thrive best in moist, loose, well-drained soil.
Should be planted in spring or fall, more or less superficially. In fact, the crown (the part of the plant where the foliage meets the roots) should not be more than 3 cm deep. Irrigation must be regular, so that the soil is constantly humid. To maintain the vigor of the plants and ensure that they flower profusely, it is necessary to divide the very large, excessively populated tufts, and to remove the scapes -trying not to damage the crown- when the plants have finished flowering.
Pests that affect daylilies are snails, slugs, and aphids. Some fungal diseases (those produced by different species of fungi) can attack these plants, however, they are generally quite resistant.
The multiplication of daylilies can be done through seeds or, more commonly, by division of the bushes. Sexual multiplication by seeds prevents the characteristics of the hybrid cultivar to be propagated from being preserved, so it is used only to create new varieties. The vegetative propagation, by division of the bushes, is carried out after the rest period, that is, in the spring or in the autumn. It is important to carry out this task when the ambient temperatures are not extreme (that is, it is not excessively cold because it is very late in the fall; or very hot because it is very late in the spring). In this way, newly divided plants are provided with a period to establish their root system before stress produced by summer heat or winter frost. The mechanics of the division of the bushes consists of extracting the plant from the ground and dividing the crown into portions that carry 2-3 shoots with their respective roots. Each of these portions must be planted immediately.
Society
In the world there are many societies of enthusiasts for the cultivation, diffusion and genetic improvement of daylilies. The first such society to be created was "The American Daylily Society" (American Daylily Society). Formed in 1946, it is the world's largest organization dedicated to daylilies. It began through the efforts of Helen Field Fischer, who hosted her own gardening show on a radio station in Iowa, USA. Aided by members of a magazine also dedicated to gardening, Fischer organized a meeting of daylily enthusiasts in Shenandoah, Iowa. During that meeting, the group decided to organize a society, initially called the "Midwest Daylily Society" (Mediwest Daylily Society). Later the name was changed to "Hemerocallis Society" and finally, at a historic meeting in 1955 in Baton Rouge, Louisiana, it became the American Daylily Society, which has more than 12,000 members from around the world. One of the responsibilities of this society is to document the registration of new daylily cultivars, since it is the international authority on this matter.
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