The Genesis Of Cypripedium Hybrids

by Carson E. Whitlow*

     With the hardy Lady's Slipper Orchids being among the most beautiful of our native wildflowers, you would think that they would have long since been hybridized. Unfortunately, there have been several obstacles to this occurring, not the least of them being difficulties in culture and seed germination.
     The first artificial Cypripedium hybrid was accepted for registration on August 17, 1987. It was given the grex name of Cypripedium Genesis. The parents were listed as Cypripedium reginae and Cypripedium pubescens (= Cypripedium calceolus var. pubescens).
     When the "New Orchid Hybrids" listing was printed in the October 1987 issue of The Orchid Review, the following footnote provided an historical point: "Cypripedium Linnaeus is a generic name re-introduced into registration use upon the registration of the first grex derived from true Cypripedium species. (Its earlier use in registration, for grexes which were truly Paphiopedilum, was discontinued in 1968 upon published correction of all the earlier Paphiopedilum grexes to their correct generic designation)..."
     Cypripedium Genesis was one of a dozen or so Cypripedium hybrids made in the spring of 1978. It, along with several others, produced seedlings which were removed from flasks and placed in the beds the following year. Tom Hillson of Ames, Iowa, had developed the flasking medium used. Together, we had developed the seedling development techniques. Approximately 90 seedlings of Cypripedium Genesis were planted. Mortality was high and by 1982, only two seedlings survived. The other hybrids had long since vanished.
     In the fall of 1982, the seedlings were transferred to another bed, where they continued to grow but seemed to indicate they were getting too much sun. In the fall of 1985, they were moved to a slightly shadier area. The next spring, only one seedling appeared. This remaining seedling had developed two growths the year before and continued with the two growths to the spring of 1987, when it bloomed.
     On the strongest of the two growths, a well-developed flower was produced. However, an insect larva found it most enticing and ate a hole in the side of the pouch and part of the staminode. The other growth produced a deformed flower, which was removed.
     The flower, on opening, exhibited quite a bit of yellow. But this faded to off-white in a manner similar to what is found in some specimens of Cypripedium X favillianum (a natural hybrid of Cypripedium candidum and Cypripedium calceolus var. pubescens). The sepals and petals are overlaid with reddish purple striations. The lip likewise is covered with more profuse striations, which flow from the opening of the pouch. The color of the striations changes to a nice lavender as the yellow fades.
     The shape of the flower is very much like Cypripedium pubescens except that the petals are more rounded on the end and generally have wavy edges instead of being twisted. The plant itself easily could be mistaken for Cypripedium pubescens as well.
     Whereas Cypripedium Genesis took nine years to reach maturity and bloom (due, most likely, to grower error and neglect when it needed attention), the indications are that four years to first flowering may be a reasonable expectation.
     A second Cypripedium hybrid bloomed April 22, 1988. It is a hybrid of Cypripedium formosanum and Cypripedium acaule and was made on May 20, 1984. The hybrid registration has been submitted with the grex name of Cypripedium Promises.
     In the case of this hybrid, approximately 18 seedlings were produced. The medium used was one developed by John Krebs of Chesterfield, Missouri. The seedlings were potted and placed in full shade under tall pine trees. Within a week, squirrels got into the plants and only six of the seedlings could be saved. They were brought inside and placed under lights. Except for two weeks in late October when they go out on my screened porch to chill and harden off for winter, they have been raised exclusively under lights. They are refrigerated at near freezing temperatures for four months to meet their dormancy requirements.
     Of the seedlings of this second hybrid, one has grown extremely well, producing five growths, four of which bloomed. The other seedlings are single-growth plants, one of which has also bloomed.
     The sepals and petals of Cypripedium Promises are green, heavily lined with lavender. The lip is white, heavily veined and tinted lavender. The dorsal sepal is shorter than in Cypripedium acaule but nicely shaped. The petals are sword-like, broader than in Cypripedium acaule yet narrower than in Cypripedium formosanum. In Cypripedium acaule, the flower bract lies over the flower, pushing the dorsal sepal down. However, in the case of Cypripedium Promises, the bract is held upright, allowing the flower to be relatively flat.
     The entrance to the pouch of Cypripedium formosanum is an orifice in the center of the lip. The entrance to the pouch of Cypripedium acaule is a slit in the pouch that runs all the way from under the staminode to the tip of the pouch and is hidden in the fold of the lip. In both species, the lip comes together and is covered at the top by the staminode. In Cypripedium Promises, the opening is a slit 1/8" wide running from (but not closed or covered by) the staminode to the tip of the lip. It is unusual but not unattractive.
     Of secondary interest are the leaves. Cypripedium formosanum has two large, fan-shaped leaves which nearly overlap. They are held well above the ground on a tall stem. The two leaves of Cypripedium acaule are more linear and pointed and do not have a supporting stem (as the species name implies). In the hybrids, the leaves are somewhat club-shaped but they open to rather broad ends. Three leaves were produced by several of the mature or nearly mature plants. However, they do not have a recognizable supporting stem.
     These two hybrids are the first of many to come in an effort to broaden the floral possibilities in cypripediums and, most of all, to increase their adaptability and ease of culture. As greater understanding is gained in seed germination and plant cultural needs, populations of seedlings will increase substantially. Although really little more than just out of the research phase at this time, considerable effort is being expended to produce and provide relatively easy-to-grow hybrids for everyone to enjoy.

* This article appeared in the American Orchid Society Bulletin, August 1988, Volume 57, Number 8, Pages 850-853.

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