By Definition hybrid means the offspring of two animals or plants of different races, varieties, species, or genera. The reproductive processes of the orchid are such that, with few exceptions, the genera do not intermingle readily, so the generic lines remain uniquely pure. It has been observed that in the few cases where, under natural conditions, members of the same orchid genus united the resulting hybrid was usually superior to either parent. An example of this is Cattleya Dowiana crossed with Cattleya gigas resulting in Cattleya Hardyana, a fine round flower of gigas mauve enriched with the iridescence of the Dowiana (yellow with dark red lip).

The purposes of the grower in developing hybrids have been to increase the stock, to increase the size and number of flowers, to change and improve the color of flowers, to improve the growth habits of the plant, and to throw strength into a weak line. Con­stant experimentation in the production of hybrids has been going on for many years. Some genera have been found to be definitely incompatible, but many others are cross fertile and can be made to produce interesting, often remarkable, flowers.

The crosses between genera are referred to as bi-generic. The most famous bi-generic cross is important for purely historic and horticultural reasons, having no commercial value. This cross was Epiphronitis Veitchii (Epidettdrum radicans, scarlet species of Mexico) with Sophronitis grandiEora (bright orange species of Brazil), recorded by Veiteh and judged by the Royal Horticul­tural Society to be the outstanding hybrid of 1890, receiving the First Class Certificate (F.C.C.).

Crosses of three genera are tri-generic. The most popular and famous is the hybrid of much commercial value, the Brassolaelio-cattleya, combining the crisp texture of the narrow-petaled Laelia with the more rounded Cattleya and adding the only outstanding feature of Brassavola, a very full, showy lip.

Even four-generic crosses have gone into some hybrids. The combination of names in such cases is so unwieldy that coined names are used: e.g. Potinara referring to the hybrid of Brassa­vola, Laelia, Cattleya, and the brilliantly colored Sophronitis.

As has been noted, certain genera will not cross with others. The failure of a plant to produce fertile seed when crossed with another plant may be the result of a difference in chromosome number, although there are many other possible causes. Many in­quiries are under way in this highly technical field of research, but published information is very limited.1 The failure of a genus to cross with another does not, however, entirely rule out hybridiza­tion. Cymbidiums do not combine with other genera, but crosses within the genus have come in for their share of glory, the progeny being much improved in form, shape, texture, and clear­ness of color. Hybrids between species of the same genera, such as the Cymbidium crosses, are called interspecific hybrids as dis­tinct from the intergeneric variety.

Calanthe Dominyi, the first orchid hybrid produced under greenhouse conditions, a union of C. Masuca and C. furcata, was developed in 1853 by a grower for Veiteh and Sons at the sug­gestion of John Harris, an Exeter surgeon. The production of hybrids has, since that time, attained such proportions as to make listing and classification a task of the first magnitude. Sanders7

1 Dr. Gustav Mehlquist, of the Missouri Botanical Gardens, has published cytological findings on Cypripediums and is now reported working on Cym­bidiums. Dr. Robert Duncan has published articles on chromosome numbers in Cypripediums in Amer. Jour. Bot. 32:506 and Orchid Digest, Sept.-Oct. 1947- Complete List of Orchid Hybrids, published in 1947 under the sponsorship of the American Orchid Society, requires 566 pages to list registered hybrids through 1 January 1946. There was no space in that fat volume for description or data on culture. The interested grower must compile his own records. Material may be obtained from personal observation, from conversation with fellow growers and experts, and from bulletins of the many orchid socie­ties and occasional articles in horticultural bulletins such as those issued by the Missouri Botanical Gardens and New York Botan­ical Garden. Much information may also be derived from the catalogues of commercial orchid establishments.

As one of them has commented, most growers 'are too busy growing orchids to find time to write,' but the exceptions to this rule give some insight into the problems for which a solution is sought through hybridization. Everest McDade has published in­teresting material on changing the blooming period of certain genera, particularly the Cattleya and allied groups, so that the popular whites come in the busy season from Christmas through June rather than from July to December.2 His conclusion is that, if the blooming season in the hybrid is to be influenced, it is necessary to choose parents with a known, dependable, dominant blooming season. Cattleya Mossiae, commonly called the Easter orchid, has the tendency to postpone summer blooms till fall and winter blooms till spring. Cattleya Mossiae Reineckiana, white with a colored lip, or some of its more available hybrids is of value as a parent because it can be depended upon to bloom in May or June. Cattleya Mossiae Wagnerii, the pure white form, or certain of its hybrids pulls progeny toward May and June. Cattleya gigas is used to advance reluctant bloomers to the desirable season from December to June.

The securing of yellow color is another problem that has been tackled through hybridization. Yellow is desirable in an orchid flower but difficult to obtain. The pollen of yellow-flowering orchids is frequently infertile, and even many of the yellow hybrids seem lacking in some vital element, producing crippled growths. Yellow color derives chiefly from Cattleya Dowiana aurea, which is of clear golden tone, with a rich velvety maroon or crimson lip and splashy gold stripes in the throat. Also used are Cattleya bicolor, a greenish-bronze species of Brazil, and Laelia tenebrosa, with purplish-brown sepals and petals and a purple lip. The latter in some instances gives a bronzy sheen or coppery overlay to a dominantly purple flower, he. luminosa aurea (Cattleya Dowiana aurea x Laelia tenebrosa), by Charlesworth in 1901, has been fre­quently used in hybridizing with a pleasing iridescent result.

Perhaps the greatest triumph of the hybridizers has been the Brassolaeliocattleya. The Cattleya had been found to cross most readily with Brassavola Digbyana, insignificant except for an extra-large frilled lip, to produce well-shaped flowers with a full, fringed lip. The Brassocattleya, in spite of size and beauty of lip and color, frequently has the disadvantage of 'starry,' narrow sepals and petals as well as poor texture, so that it does not keep well. It also rarely blooms with more than one flower, although there are outstanding exceptions, such as Be. Mme Charles Maron (B. Digbyana x C. gigas). By adding Laelia to the Brassocattleya perfection was reached. The Laelia stands firmly erect, and its influence was to strengthen the weak dorsal of the simpler cross. The size of the resulting Brassolaeliocattleya is enormous and the color range wide. Many of the modern Brassolaeliocattleyas are so full and round that the hand can be hidden by a single flower.

The grower will be enabled to work toward those qualities he most values by keeping careful records of his hybrids. In compil­ing such a record the following suggestions may prove of value.

1. On first receiving a choice hybrid, record the name, par­
   entage, grower, and, if possible, the hybridizer and the date of
   hybridizing.
2. From personal  observation record  the date of blooming,
   quality, color, texture, and number of flowers.
3. By comparing notes with other growers, note possible varia­
   tion in color and blooming time. An exciting phase of orchid study is the tracing of the family tree of any given hybrid. Occasionally the direct antecedents of a hybrid cannot be determined, but usually the original species' parents can be ascertained and will provide a useful key to the future of the hybrid, its appearance, habits, and successful cul­ture. There are several types of family tree. These examples should give the reader an idea of how a family tree might be prepared in any particular instance.

The family tree of the primary hybrid is rather simple.
Epiphronitis Veitchii Veitch, 1890
(Small, bright, orange-scarlet flower.)
Cattleya Fabia Veitch, 1894
(Large, round, dark pur­ple with iridescent sheen.)
Epidendrum radicans (Tiny spray type of flower, growing weed rank, bright red.)
x Sophronitis grandiflora (Flowers 3 inches, scarlet, orange-yellow lip, one-flowered.)
Cattleya  Dowiana   (Flower   golden   yellow,   large, maroon-red lip, velvety.)
x Cattleya labiata (Flower mauve, large, round petals and sepals, good lip.)
Secondary hybrids are more complicated.
P. amabilis (Large, white, yellow keel and spotted red on lip.) x
P. Rimestadiana (var. of amabilis, stronger, blooms all year.)
P. Gilles Gratiot x
P. Rimestadiana
C. insigne (Flowers whitish, flushed, lined and spotted with red.) x
C. Parishii Sanderae (White flower 4 inches, lip 2 yellow keels, cen­ter yellow, richly marked with purple.)

The pedigrees of some famous plants read like lines of royalty. Cymbidium Swallow, descended from the very distinguished C. Alexanderi, Westonbirt var. (F.C.C., R.H.S.) and the equally distinguished C. Pauwelsii, Comte d'Hemptinne var. (F.C.C., R.H.S.), has a bewildering number of excellent qualities. Among them are its variation and purity of color, whether it be cream, flush-pink, or yellow-pink, or fine white—the latter surprising in view of the fact that the Pauwelsii is intensely colored. The shape and texture are round and crisp. The habit of growth is strong. Cymbidium Alexanderi, the first parent, was developed in 1911 by Sir George Holford of Westonbirt (home of many famous crosses), Tetbury, Gloucester, England. Cymbidium eburneo-Lowianum, hybrid of eburneum (white and creamy-white, deep yellow disc on lip), and Lowianum (yellowish-green with cream lip, rich crimson border) were combined with insigne (whitish, suffused pink, lip dotted dark crimson, and all flushed crimson-purple) to form a parent of such outstanding worth that it is world famous. Cymbidium Pauwelsii, developed by Pauwels in 1911, while of simpler pedigree (insigne x Lowianum), is also widely known as a satisfactory parent.

A third type of family tree is more complicated, as illustrated by the ancestry of one of the Brassolaeliocattleya.
Brassolaeliocattleya Emilia
H. G. Alexander, 1940
(Flower, sepals, petals, and lip, mauve, double-frilled lip, large, crisp texture)
Blc. Ursula                 Lc. The Moor
Brassavola Digbyana      Lc. Sargon     Lc. Canhamiana
(Flowers small,   '
greenish-white,    C- Mossiae      L-
extremely large    (Rlch Pur- lip) pie but with spid­ery petals.)
C. Hardyana                Lc. Lustre
C. Dowiana C. gigas           C. Lueddemaniana     Lc. Callisloglossa
(Gold with      (Mauve, fine   (Amethyst with
mauve throat.)        shape, darker     white lip.)
lip.)                                ,______ .______ ,
C. gigas   L. purpurata

Some specific developments in the hybrid field are interesting enough to merit brief review. A great deal has been done in the development of fine Phalaenopsis hybrids. They are not of great number but are of outstanding quality. Gravel culture has been responsible for the growth of large round Phalaenopsis of compli­cated parentage. Phalaenopsis Altadena (P. La Canada x P. Psyche) and P. Winged Victory (P. Elizabethae x P. La Canada), by Orchid Research of California in 1946, are whites of extreme size, leathery texture, and round shape. Phalaenopsis Reve Rose (P. Algers x P. Schilleriana), by Veitch in 1932, is capable of producing flowers of dusky rose, lacking the veining considered unattractive in the pink Schilleriana. Phalaenopsis Gilles Gratiot (P. amabilis x P. Rimestadiana), by Dr. Gratiot in 1920, is a primary hybrid found in the background of many later hybrids.

Among the hybrids showing great promise of improvement over the parents are the Odontonias. Odontoglossum crispum and its hybrids are spray flowers of outstanding texture, color, and beauty, but for some growers they present a problem in blooming. Simi­larly, Miltonia is a plant of fragile characteristics and difficult for some growers to treat successfully. Miltonia blooms, with the dis­tinctive butterfly mask around the lip and throat of the pansy face, are of delicate beauty and unsurpassed color. The Odon­tonias resulting from the union of these two species retain the beauty of both and in some way have their life and growth habits strengthened so as to grow successfully in the Cattleya house.

The Odontonias bloom from April to May. Many of the hy­brids are sterile and, owing to the delicacy of the parent plants, seed is difficult to grow, so the plants are rare. Among the out­standing Odontonias, with parent plants and growers listed, are:

Odontonia Avril Gay (M. Duchess of York x O. Serapis). Rosy-mauve to crimson-purple on white ground. Charlesworth.
Arima (M. Nesta x O. Purple Queen). Sepals and petals chocolate-red; lip red and white with golden disc. Charlesworth.
Alexandra (M. Merope x O. Crethus). Sepals and petals purple; lip white spotted with red. Charlesworth.
Cardinalis (M. Lyceana x O. Purple Queen). Petals cardinal red tipped with white; lip white with red spots. Charlesworth.
Tyana (Odtna. Nesta x O. St. James). Petals mahogany-red, tipped and spotted white; white-dusted lip. Black and Flory.
Olga (Odontonia Thisbe x O. crispum). White with chest­nut-red lip. Charlesworth.