American Rose Annual: 1932
Rosa Gigantea and Its Allied Species
Rev. George M. A. Schoener
Santa Barbara, CA
As the basis of most of my hybridizing experiments has been Rosa gigantea and R. macrocarpa, I have been familiar with both of those species for more than twenty years, and also have had direct contact with the very men who first discovered them in their natural habitat.
Rosa gigantea was found in the year 1888 by the late Gen. Sir Henry Collett in the Shan Hills, Upper Burma, at an elevation of 4000 to 5000 feet. He sent dried specimens to Kew and to the Calcutta Royal Botanic Garden, and eventually others were sent to Crépin with the suggestion that the species be called "gigantea", because of its giant growth. The species was re-collected by W. Hancock and Dr. A. Henry in the province of Yunnan, China, although their specimens show considerable variation from Collett's original.
The most distinguishing features of Gigantea are its giant growth and nearly evergreen foliage. The stems are long and trailing, with stout, hooked prickles. Leaflets are five, large, oblong, finely and simply toothed, the terminal one 2.5 to 3 inches long, the side ones distinctly stalked, olive-green, and glaucous on both surfaces. The flowers are large, solitary, with white petals over 2 inches long. In its native India, the blooms are said to be as much as 15 inches in circumference, and I have had them in Santa Barbara more than 5 inches in diameter, which is by far the largest flower of any wild rose. The fruit is globose, naked, bright red, over a half-inch in diameter, and this is one of the essential characteristics of the genuine species. The carpels are brown, shining, glabrous, .25 inch in diameter, from 6 to 10 in a hip.
The honor of bringing R. gigantea into the United States belongs to the late Dr. Franchesci Fenzi, a native of Florence, who died a few years ago in Tripoli. Dr. Franchesci, as he was known to his friends, maintained a garden in Santa Barbara for more than a quarter of a century, and introduced a great many valuable foreign plants into southern California. According to his son, Camillo Franchesci Fenzi, R. gigantea was imported by his father directly from India about 1904. In the American Rose Annual of 1921, page 175, he is erroneously credited with being the originator of Belle of Portugal. The fact is that, having contact with all the leading horticulturists in the world, he imported Belle of Portugal from the Lisbon Botanical Garden, where it was originated in 1905 from a cross between the old Tea rose, Souvenir de Mme. Léonie Viennot, and R. gigantea. From Dr. Franchesci's garden in Santa Barbara, Belle of Portugal gradually found its way over California and into other southern states.
Dr. Franchesci produced a few Gigantea hybrids. His Montecito and Montariosa are the two best known to me. Both are seedlings of R. moschata by R. gigantea, and both show very dominantly the musk character.
Amongst European workers with R. gigantea, the old Nabonnand firm at Point Antibes, near Cannes, sent out some very good hybrids. Lady Johnson, of a beautiful orange shade somewhat resembling Irish Fireflame, is probably the best. Before that, in 1909, H. Cayeux, also in southern France [Cayeux was in Lisbon at the time], produced Etoile de Portugal, a large, well-made flower of a beautiful shrimp-pink, strongly climbing, recommended for its superb new color among climbing roses. Another good production was Reine de Portugal, of beautiful orange-flame color. Its large, glossy, mildew-immune foliage was a most conspicuous feature of this Gigantea hybrid, which came into my hands around 1920.
Since 1924, Mr. Alister Clark, of Victoria, Australia, has become one of the most successful workers with Gigantea. His variety Harbinger, with brilliant red blooms, is singularly beautiful but is not free from mildew. His Golden Vision and Kitty Kininmonth are also excellent additions to this type.
Beginning in 1912 at Brooks, Ore., continuing at Portland until 1917, and since then at Santa Barbara, Calif., I have made Gigantea the base of practically all my hybridization work. Nearly 1200 different combinations have been made, including such new alignments as Rugosa hybrids with Gigantea hybrids. All of the best-known Hybrid Teas and Pernetianas have also been used with Gigantea and other fine species, including those native to California and Oregon, R. nutkana taking the leading role, and at various times, also R. lucidissima, R. Leschenaulti, R. laevigata, R. bracteata, and this year, R. stellata.
It will help toward a clear understanding to know that a little research over the territory considered to be its natural habitat discloses that there are several independent forms differing considerably from the true type of R. gigantea Collett, especially in the foliage and in the fruit. For example, R. gigantea imported directly from India by Franchesci in 1904 shows no foliage glabrous on both sides, but rather a dull green under-surface. Its fruit is oblong, about .5 inch, shiny scarlet-red, and the seeds are also much smaller than those of the genuine R. gigantea Collett. It is true that the foliage is evergreen and mildew-free, and hence, excellent breeding material.
There is another form, called R. odorata gigantea Rehder & Wilson, found in southern China, which has hardly any characteristic marks of the true Gigantea type, either in foliage, flower, or fruit. It looks much more like a natural hybrid between Gigantea and Moschata or Leschenaulti. It is certain that Rehder & Wilson's R. odorata gigantea had nothing to do with any of the Gigantea hybrids known today, as proved by foliage alone. It is equally certain that neither Nabonnand nor Mr. Alister Clark used R. odorata gigantea Rehder & Wilson in their hybridizing. The hybrids of Mr. Clark and also those of Nabonnand demonstrate unmistakably that they used R. gigantea Collett as a seed or pollen parent.
Besides R. gigantea Franchesci and R. odorata gigantea Rehder & Wilson, there are other types more or less near the genuine. Seed which was imported by me directly from Assam and Burma produced two forms of highest excellence which differ in several essentials from Collett's Gigantea. The hips are smaller, although shiny scarlet-red, but the seeds are not as large. Both are perfectly resistant to mildew and are evergreen. The only difference between these two forms is that one has larger foliage than the other, and also somewhat stronger growth. The flowers of the one from Assam are larger, and lemon-yellow in the bud. Both are excellent plants of highest merit. Such diversity of characteristics makes it apparent that from section to section throughout India, Gigantea is rich in many representatives of characteristic types. But up to date, nobody can definitely say which particular type is the genuine and best one.
In my records of combinations, the name R. gigantea Hybrid frequently appears, either as seed or pollen parent. This form looks like a hybrid between R. macrocarpa and R. gigantea Collett. For distinction's sake, we will call it R. gigantea Schoener. Its outstanding characteristic is the fairly large, green fruits which never turn yellow or red. The foliage is the most beautiful of all of them, distinctly evergreen, glabrous, with the same gloss on both surfaces of the leaflets, and is immune to mildew. Its flowers are larger than any of the others and at first are faint lemon-yellow, gradually turning white.
Besides the Indian representatives of R. gigantea, we have those from China which show much differentiation, but hardly any of them measure up to the quality of R. gigantea Collett or R. gigantea Schoener. As they often show inflorescence similar to R. moschata and the flowers are not much larger than that species, they seem to wander far from the excellence of the more tropical Indian Gigantea. Indeed it seems that R. odorata gigantea Rehder & Wilson is representative of the species found in southern China.
|*Rehder calls this R. odorata var. Pseudoindica. In fact, throughout this article Father Schoener evidently uses R. chinensis as a synonym for R. odorata Sweet, which is R. Thea Savi, R. chinensis var. fragrans Thory, and R. indica var. odoratissima Lindl. See Manual of Cultivated Trees and Shrubs, Rehder.ARA Editor.|
It remains for me to say something about R. macrocarpa. This exceedingly beautiful species was found by Sir George Watt in Manipur in 1888. On first glance, Crépin believed it was identical with R. gigantea, but Sir George, an authority on Indian roses, considered them fully distinct from each other through several essential characteristics, especially the larger foliage of R. macrocarpa, with 5 to 7 leaflets, its very large yellow fruits, not red as in Gigantea, and above all its deep yellow flowers, somewhat larger than those of Gigantea. Because of its large yellow fruit, he first described it under the name of R. xanthocarpa, which means yellow-fruited. In an unpublished diary Sir George goes on to speak about this magnificent species in the following glowing terms:
An extensive climber, running over trees and forming at first straight unbranched stems, as thick as an arm, younger ones with a soft grey-brown bark and here and there short sharp hooked prickles; above completely ramified until it envelopes the tree on which it is found. It thus produces a truly superb effect, and when seen from a distance, causes the trees to appear like magnolias, with large yellow flowers. The leaves when young have a rich brownish green tint, when older they become pale shining green; leaflets 5 to 7, ovate-long, acuminate, shortly and sharply serrated, the terminal one on a long petiole (1 inch), the others almost sessile. Prickles very few on the flowering branches, short, sharp, recurved; on the young flowerless shoots large, massive, flat, recurved. flowers solitary or two or three in the axils of the terminal leaves of the shoots; flower-buds very large, smooth, glaucous, calyx-teeth erect in the bud, long, lanceolate, acuminate, quite entire, sharply reflexed when the flower is fully expanded. Ovary (the hip) glabrous; achenes very large, massive, sparsely hairy, with long protruding free styles, and yellow globular stigmas. Stamens numerous, anthers orange-colored. The fleshy hip or fruit is eaten by the Nagas, the natives of that section of India. It becomes as large as a small apple, and is smooth, glabrous, yellow (certainly never red, as has been said of the species grown in Europe) and sweetly scented.
This species seems to be possibly allied to, though quite distinct from, Rosa chinensis Jacq., and may probably be the true ancestor of Tea roses. It was nowhere observed near villages, but was found frequenting the forests, far away from human dwellings. Since the Nagas do not cultivate flowering plants and seem never to have done so, there is no reason to doubt but that Rosa macrocarpa is, as stated, a truly indigenous plant on the north-eastern mountains of the Burma-Manipur frontier.
Since we know now upon the authority of Sir George Watt that both R. gigantea and R. macrocarpa are probably natural hybrids or subspecies of R. chinensis Jacquin, we must assume that they are not more tender than R. chinensis itself or any Tea roses that descended from that species. A good two-thirds of all the existing Tea roses are dwarfs, and within a reasonable cycle of hybridization through four or five generations, good dwarf varieties from these two grand species ought to be abundant, according to commercial needs. Both species are of paramount importance for future breeding in this country in our effort to get more disease-proof types of foliage. Specialists may choose between either the narrow 7- to 9-foliate leaflets of R. gigantea and the 4 to 7 leaflets of the broader and larger foliate of R. macrocarpa, with the petioles often formidably armed. The yellow color of the petals of R. macrocarpa is deep and lasting, wherefore yellow roses quite distinct from the Pernetiana origin are possible. Because of their close relationship with R. chinensis, it is plain that both species will make easy combinations with any Hybrid Tea or Pernetiana variety, according to the desire of any clever specialist who has a combination for any distinct improvement in mind; for example, a long tapering bud on a stem of over two feet which is considered ideal for cut-flower purposes. We can take for granted, on the strength of the gigantic growth of these two species, that amongst future Macrocarpa and Gigantea hybrids many may be improvements over the forcing varieties of today. Dr. Crocker, Director of the Boyce Thompson Institute, Yonkers, N. Y., who so generously germinated our hybridized seed for the past three years, made this significant statement in a letter last April:
I feel you will have greenhouse roses, produced by your crossings, that are so much better than any others now grown, that there will be no comparison. I have been especially struck by the long, conical buds that appear on many of these Gigantea hybrids, and the wonderful coloring and texture of the petals. Some of the foliage is wonderful. I am more convinced now than ever that good greenhouse roses must be derived from introducing new species-blood rather than from continuous crossing and recrossing of Teas, Hybrid Teas, and Pernetianas.Dr. Crocker's statement confirms my own assertions, and it is rather more than a mere statement of opinion, since it was accompanied by a report based on observation of the 20,000 seedlings in his care which were the results of 1200 different combinations between other pure species and the best-known pedigreed varieties, with R. gigantea and R. macrocarpa.
It would seem fitting to say also a word about R. Leschenaulti Wight & Arnott. Thory, in Redouté reports this very beautiful rose as R. sempervirens var. Leschenaultiana, thereby referring to its evergreen character. Its leaflets are 5 to 7, elliptic, oblong, 1.5 to 2.5 inches across, numerous, in large corymbs; the buds very acute; the fruits globose and red.
This beautiful wild rose has been considered a wild form of R. moschata var. Mill, but it is a perfectly good and distinct species, especially in evergreen characteristics. While it may be closely related to R. sempervirens Linnaeus, it differs from that south European species in its more robust habit, larger flowers, and entirely different foliage. The distinguished French naturalist, Leschenault de la Tour, found it about 1834 on the higher levels of the Neilgherry Hills and Palni Mountains in south India where it is plentiful. It was more recently found by Dr. Henry in Yunnan, China, which amounts to a geographic distribution of over 1000 miles from the south of India to Yunnan. It is the only wild rose in the temperate wilds of southern India, as its closely allied species, R. Lyellii Lindley, is found exclusively on the lower hills of Mysore. According to its evergreen foliage, the suggestion is evident that it also is closely related to R. gigantea, the difference being that its inflorescence is similar to R. moschata.
Rosa Leschenaulti is described by those who have seen it in its native mountains as being so luxuriant that it festoons the trees to a height of 60 to 70 feet with trails of pure white flowers, making a sight never to be forgotten. The violet-tinted stems are powdered with a fine glaucous dust which resembles the bloom on a fruit and adds to its striking appearance. It is one of the most promising untried rose species. As I had this lovely species in Oregon in my collection at Brooks, I speak from personal experience. Rosa Leschenaulti stood out conspicuously as promising.
But the paramount question is, Can all the desirable characters of this species be bred into new types of garden roses? The answer is that the science of genetics applies to roses the same as to other plants. The Mendelian law of inheritance has been verified over and over. Roses have, as other plants, differentiating character units which determine the differences between one species and another. It cannot, therefore, be otherwise that in hybridizing two species which we select for a definite purpose, we should be able to retain in a hybrid a certain unit character of one species which will act as dominant while the other unit of the opposite species will be recessive. This is universally accepted as an unshakable law of nature.
What more could be wanted? We now know as a positive natural law that the valuable characteristics of roses can, indeed, be retained at will in sufficient hybridization experiments.
The problem of sterility raised by Dr. C. C. Hurst, whose septets of chromosomes seemed to presage a new rose classification, seems less hopeless now than then. Dr. Hurst assumed that a simple diploid species from the south could not be successfully crossed with a polyploid species of the north, because of sterility in the hybrids. My extensive experiments with more than 1200 different combinations, always between diverse species of the south and north, have proved the fallacy of Dr. Hurst's assertion, and that there are no barriers or causes for sterility in the sense he postulates, because the chromosomes are not the exclusive carriers of the hereditary mechanism. Very significantly, Dr. Kathleen B. Blackburn, in the American Rose Annual for 1927, page 58, blasts the faint hope to find a surer solution for hybridizing problems by the following sweeping conclusion:
Through consideration of this account of the chromosome number and behavior in the genus Rosa, the experienced breeder may find, perhaps, some indications as to where to look for fertile crosses, but on the other hand, he would be a bold man who attempted to say definitely from this evidence that a hybrid would not be fertile, since the rose apparently possesses a remarkable ability for getting out of a tight corner.Since we know that the unevenness of the chromosome septets has nothing to do with the sterility of roses, we can rest assured that undreamed-of hybrids and new types of roses await us if we have persistence enough to carry out our experiments through the most diverse species and varieties.
1) Simple dominance is not the universal law. Many traits are polygenic, while others are co-dominant.
2) When widely separated species are crossed, the "hereditary units" are often complex linkage groups. In crosses of Raspberries with Blackberries, the distinctive characters of leaf, cane and fruit tend to be inherited as single unit. The same holds true in Roses. Unfortunately the concept of "super-gene" was not discussed until 4 years after Hurst died.
3) Hurst spoke of sterility in the Darwinian sense of "not fully fertile". He thought that Rosa damascena may have originated as a hybrid of the southern diploid R. moschata and the northern tetraploid R. gallica.
4) Differential pairing of chromosomes does play a role in the reduced fertility of some hybrids, and can greatly reduce the frequency of segregation of characters in the hybrid progeny. That is, if we cross Rosa foetida with a Hybrid Tea, we cannot expect fully fertile, deep yellow Hybrid Teas in the F2, and it will take even longer to eliminate the susceptibility to blackspot.]