Cytologia 37: 59-81, 1972

Chromosomes of from Japan and South

Charles H. Uhl and Reid Moran

Division of Biology, Cornell University, Ithaca , N. Y. 14850 and Natural History Museum, San Diego , California 92112, U. S. A.

Received June 10, 1970

About 35 species of Crassulaceae are native to Japan and Korea, though about twice as many have been proposed. The most recent floras are those of Chong (1957) for Korea and Ohwi (1965) for Japan. Chong recognized Meterostachys (1 species), Orostachys (3 species), Rhodiola (2 species), and Sedum (14 species and 1 variety), for a total of 20 species and 1 variety; we would recognize about 16 of these and add one more (S. viridescens Nakai). Ohwi included these genera in Sedum. Besides two cultivated species, he recognized 32 species and 6 varieties and mentioned three other species; we would recognize about 29 of these species and add two more (S. sikokianum Maxim., S. zentaro-tashiroi Makino). Cytological data have been of considerable value in treating with problems of relationship in the Crassulaceae (Uhl 1961, 1963), and the present work is part of a general cytotaxonomic study of the family. Although chromosome counts have been reported for a few Japanese and Korean species there has been no systematic cytological survey of the family in this area before. From late 1953 through 1956, Moran travelled sporadically but widely in Japan and South Korea; he also visited Okinawa and the Philippines. He made about 350 collections of Crassulaceae, taking herbarium specimens of those in and cytological material of those in bud and usually collecting living to be grown in Berkeley and in Ithaca. The first set of field-collected specimens is in the Uni versity of California Herbarium at Berkeley; herbarium specimens from cultivated plants are there or in the Wiegand Herbarium or Bailey Hortorium, Cornell Uni versity. Some buds were fixed in the field, but most counts are from plants cultivated for several months or more. Buds were fixed in modified Carnoy's solution (3 parts chloroform, 2 parts absolute ethanol, 1 part glacial acetic acid), the anthers were squashed in aceto carmine, and meiosis was studied in the microsporocytes. The slides were then made permanent. Photographs of the chromosomes are from permanent slides.

Orostachys Orostachys Fisch., with perhaps fewer than a dozen species, ranges from Japan to the Ural Mountains. Some of the species are extremely variable, and some of the taxonomic problems are difficult to resolve from herbarium material alone. 60 Charles H. Uhl and Reid Moran Cytologia 37

Although Japanese and South Korean plants have been named as eight species, we treat them as three variable species and one variety. Orostachys japonicus (Maxim.) Berger may be referable to some earlier-named mainland species, whether O. erubescens (Maxim.) Ohwi or O. fimbriatus (Turcz.) Berger; but this is uncertain. Besides topotypes of O. furusei Ohwi and O. genkaensis Ohwi, the collections studied included some representative of O. boehmeri (Makino) Hara (e.g. 5440) and of O. aggregatus (Makino) Hara (e.g. 5434). On the basis of 58 collections of four species, the apparent basic karyotype of Orostachys is of 12 rather small gametic chromosomes (Figs. 1, 3, 4). Since many of the plants reproduce vegetatively, it is perhaps not surprising that the 58 collec tions include nine triploids, three tetraploids (Fig. 2), and one heptaploid. In fact, in the Korean O. minutus (Komarov) Berger, nine of the twelve collections studied were triploid (Figs. 5-7) or tetraploid, meiotically irregular, and probably sexually sterile.

Figs. 1-8. Metaphase I chromosomes of Orostachys and Meterostachys, •~2000. 1-2, O . japoni cus, 5167, n=12; 5458, n=24. 3, O. malacophyllus, 5250, n=12. 4, O. minutus, 5161, n=12. 5-7, O. minutus triploid, 5221: 12II-III+4I; l2II-III+7I; l2II-III+9I. 8, M. sikokianus , 5160, n=16.

Soeda (1944) reported n=12 for a cultivated of "Cotyledon spinosa L." (=O. spinosus (L.) Sweet), but we wonder whether this might not be O. japonicus, which is much more likely to be grown in Japan.

Meterostachys Meterostachys sikokianus (Makino) Nakai (=Sedum leveilleanumHamet) is a variable speciesof Korea and southern Japan, resemblingOrostachys in vegetative structures but differingin inflorescenceand . To judge from nine collections from widely scattered localities, it has a basic karyotype of 16 rather small gametic chromosomes (Fig. 8) and thus is sharply distinct cytologicallyfrom the species of 1972 Chromosomes of Crassulaceae from Japan and South Korea 61

Orostachys studied. We are inclined to maintain this monotypic genus, at least pending fuller knowledge of the other species of Orostachys.

Sedum

Five sections of Sedum (sensu Berger 1930) are represented in Korea and Japan . Section (or subgenus) Rhodiola is represented on Honshu and Hokkaido by S. ishidae Makino and by the 11-chromosome race of S. rosea (L.) Scop. S. rosea is a highly polymorphic circumboreal species which in North America also has an 18-chromosome race (Uhl 1952). It appears to be common in Alaska, but no re ports have been made of its chromosomes there.

Figs. 9-21. Metaphase I chromosomes of Sedum Section Telephium, •~2000. 9, S. cauticola,

5553, n=24. 11, S. pluricaule, 5270, n=11. 10 and 12, S. sieboldii, M5554, U137, n=25. 13, S. sordidum, 5241, n=12. 14, S. spectabile, 5527, n=25. 15, S. telephium, 5565, n=12. 16,

S. verticillatum, 5537, n=ca. 48. 17, S. viride, 5546, n=12. 18, S. viridescens, 5511, n=23. 19-21, S. viviparum triploid, 5282: 12III; 12II-III+2I; 11II-•‡+4I.

Section Telephium includes about 20 species, of which about 11 occur in this area. All 11 have now been studied cytologically. The basic chromosome number is almost certainly 12, though the Chinese S. tatarinowii Maxim. has n=10 (Baldwin 1937), the central Asian S. ewersii Lodd. and the East Asian S. pluricaule Kudo (Fig. 11) have n=11, and several polyploids occur. S. sordidum Maxim., S. 62 Charles H. Uhl and Reid Moran Cytologia 37

telephium L., and S. viride Makino all have n=12 (Figs. 13, 15, 17). S. telephium also occurs in Europe, where it is represented by diploids, triploids and tetraploids (Baldwin 1937, Turesson 1938). Sugiura's (1937) report of n=18 in this species was probably either an error or based on a somatic count of a triploid. Four collec tions of S. cauticola Praeger from Hokkaido had n=24 (Fig. 9). The widely cultivated S. spectabile Boreau (Moran 1964) and S. sieboldii Sweet both have n=25 (Figs. 14, 10, 12) as found also by Baldwin (1937) and Soeda (1944). The former number has been verified from four native populations. S. viridescens Nakai of Korea, for which the later name of S. taquetii Praeger has generally been used in cultivation (Moran 1965), has n=23 (Fig. 18). On the basis of two collections, S. verticillatum L. appears to be octoploid, with n=48 (Fig. 16); however this is a widespread and variable species, and more collec tions need to be studied. S. viviparum Maxim. which reproduces profusely by means of bulbils formed in the , was triploid (2n=3x=36) in both collections studied (Figs. 19-21). The only plant of S. erythrostictum Miq. studied was meiotical ly irregular. Soeda (1944) reported a somatic chromosome number of 50 in a cul tivated plant of this species and also found irregular meiosis. Soeda's report of n=11 for S. verticillatum (in contrast to our count of n=48, probably) suggests that he may have had a different species. His counts for S. cauticola, S. pluricaule (as S. yezoense) and S. sordidum agree with ours. With the possible exception of the distinctive S. sikokianum Maxim., for which we have no count, the section Aizoon is a polyploid complex with a basic chromosome number of 16 (Figs. 22-25). We follow the usual, if perhaps somewhat arbitrary, practice of dividing the plants of our area (again excepting S. sikokianum) into two species; but some plants could not be assigned with complete assurance. S. aizoon L., the larger of the two plants, may be regularly hexaploid, but S. kamt schaticum Fisch. is much more variable: ten Japanese and Korean collections were diploids with n=16 (Fig. 22), one other had the same, with an extra, probably accessory, chromosome (Fig. 23), six were tetraploids with n=32 (Fig. 24), five were probably hexaploid with n=48 (Fig. 25), and three each apparently were pentaploids and heptaploids. Irregularities at meiosis increase approximately with the degree of ploidy, though the odd-ploids are especially irregular. We have the impression that sexual reproduction may not be very important to the maintenance of some of the polyploids, but we have no experimental evidence. Soeda (1944) reported diploid S. kamtschaticum from near Sapporo and near Tokyo and triploid and tetraploid plants ("from Amur?") in cultivation. He also reported S. aizoon from Hokkaido as tetraploid (2n=64). The remaining species are all more typical of Sedum and belong to the section (or subgenus) Sedum (=Seda genuina Koch), though monocarpic species have been placed in the artificial section Epeteium Boiss. All are rather small, yellow-flowered annuals to perennials. Some are extremely variable, and the exact number of species is uncertain. Fourteen-probably all but three of those occurring in this area - have been studied cytologically, most of them for the first time. The species or complex most notable cytologically is S. polytrichoides Hemsl. sensu latiore, including S. coreense Nakai and S. lepidopodum Nakai of Korea, 1972 Chromosomes of Crassulaceae from Japan and South Korea 63

Figs. 22-39. Metaphase I chromosomes of Sedum Sections Aizoon and Sedum, •~2000. 22-25,

S. kamtschaticum, 5436, n=16; 5252, n=16+1; 4826, n=32; 5171, n=48. 26-27, S. alfredii, var.

nagasakianum, 5579, n=62; 5408, n=65. 28, S. ambiflorum, 4847, n=67. 29, S. bulbiferum, 5386, n=19. 30, S. formosanum, 5057, n=32. 31, S. japonicum, 5244, n=19. 32, S. lineare, 5446, n=36. 33, S. makinoi, 4357, n=36. 34-35, S. oryzifolium, 5407, n=10; 5230, triploid:

5III+5II+5I. 36, S. rupifragum, 5398, n=68. 37. S. senanense, 5238, n=9. 38, S. subtile, 5315, n=28. 39, S. tricarpum, 5313, n=62.

S. yabeanum Makino of Tsushima, and S. kiusianum Makino of Shikoku, Kyushu, and western Honshu. In the 39 collections studied, we have found 13 gametic chromosome numbers, from 11 to 35 (Figs. 40-52, and map, Fig. 53). The chro mosomes are always quite small, but several collections showed substantial differences in size within the set (e.g., Figs. 45, 48). Three collections were conspicuously ir regular at meiosis, and several others showed lesser irregularities. Apparently because of sexual sterility and not on the basis of cytological study, Nakai (1940) 64 Charles H. Uhl and Reid Moran Cytologia 37

suggested that S. lepidopodum might be a triploid form of S. kiusianum. The plants we include in this complex are fairly diverse; but chromosome number is very imperfectly correlated with morphology and distribution. The seven northernmost collections, mainly from near Seoul, all had n=16; plants of that area, including one with n=22, are rather uniform and are narrow-leaved like S. kiusianum. Plants from within 25 miles of Pusan had seven different chromosome

Figs. 40-52. Metaphase I (except Fig. 42, Metaphase II) chromsomes of Sedum polytrichoides sensu latiore, •~2000. 40, 4761, n=11. 41, 5473, n=12. 42, 5512, n=14. 43, 5220, n=16.

44, 4772, n=20. 45, 5483, n=21. 46, 5156, n=22. 47, 4786, n=23. 48, 5574, n=24. 49, 5503, n=25. 50, 4768, n=26. 51, 4731, n=27. 52, 5533, n=35.

numbers (Fig. 53); they are less uniform than the northern plants but regularly have wider . Plants from the south coast with n=23, n=25, n=26, and n =27 are somewhat larger than other collections, with stouter stems and more stiffly spreading leaves. All six collections from Tsushima had n=24, a number not found elsewhere in the complex (though four Korean collections had n=12); this is S. yabeanum, a broad-leaved form similar to some Korean collections. The other two Japanese collections had n=25 prob. and n=35. The best taxonomic treatment of this complex remains a problem; but in view of the diversity of chromosome numbers, the proposed S. coreense, S. kiusianum, and S. lepidopodum clearly can be placed within the complex only with the cytological study of topotypes and of Chinese material including a topotype of S. polytrichoides. 1972 Chromosomes of Crassulaceae from Japan and South Korea 65

S. oryzifolium Makino, S. japonicum Siebold, and S. senanense Makino are all somewhat similar and respectively have n=10, n=19, and n=9 (Figs. 34, 31, 37). S. japonicum may be suspected of having had an amphidiploid origin from the other two or from something like them. One collection of S. oryzifolium was triploid (Fig. 35). S. bulbiferum Makino also has n=19 (nine collections) (Fig. 29). Plants of this species also form bulbils in the inflorescence and propagate vegetatively with great efficiency, and so it is not surprising that four other collections of the species were triploid. S. subtile Miquel with n=28 is similar and may be related to these (Fig. 38). S. lineare Thunb. has 36 small gametic chromosomes (Fig. 32). The related S. sarmentosum Bunge may have about the same number, but it usually displays considerable irregularity at meiosis. The latter species is very common in cultiva tion and escapes frequently. It can become a nuisance in a rock garden, where it propagates itself by means of runners and broken bits of stem. S. formosanum N. E. Brown ranges from southern Japan through the Ryukyu Islands to Formosa. Five collections from Kyushu and Okinawa had n=32 (Fig. 30), but one from Ishigaki in the southern Ryukyus had n=33. S. makinoi Maxim. is somewhat similar and also slightly variable cytologically, having n=35 and n=36 (Fig. 33). Several other species have higher numbers. S. tricarpum Makino departs from the usual Crassulaceous pattern in having fewer carpels than (three vs. five). It has 62 gametic chromosomes (three collections )(Fig. 39). S. alfredii Hance, var. nagasakianum Hara, has the same number in one collection (Fig. 26) but n=65 in two other collections (Fig. 27). S. rupifragum Koidz, probably is related to the preceding species and has 68 pairs of chromosomes (Fig. 36). The only species indigenous to the Philippine Islands, S. ambiflorum R. T. Clausen also is related to these species and has n=67 probably (Fig. 28). Allied species occur in Formosa, but no plants from there have been available. The diversity among the species in the number and size of their chromosomes is noteworthy. In the 34 species reported here, 27 different gametic chromosome numbers have been found, ranging from 9 to 68, and the chromosomes range in size from very small (e. g., S. alfredii, Fig. 27) to relatively large (e.g., S. pluricaule, Fig. 11). Some species are heterogeneous not only in their morphology but also in their karyotypes, and at least 10 species, as delimited here, have more than one chromosome number. Furthermore, the pattern of variation differs, from strict eupolyploidy in Orostachys and probably in Sedum section Aizoon to polyploidy complicated by a little dysploidy in Sedum Sect. Telephium to extreme dysploidy with no obvious basic or ancestral chromosome number in S. polytrichoides sensu latiore. These differences in patterns of change in chromosome number that have accompanied evolution are surely related to the dynamics of that evolution, but the significance is obscure. A comparable situation exists in North American Crassulaceae, where Dudleya, often submerged in Echeveria, has always 17 gametic chromosomes or a multiple (Uhl and Moran 1953), whereas various species of Eche veria (sensu stricto) have every gametic number from 12 to 34 and many higher num 66 Charles H. Uhl and Reid Moran Cytologia 37 bers, with no obvious basic or ancestral number (Uhl unpub.). Perhaps the study of certain other cytological characters may help to clarify this situation.

Fig. 53. Distribution of various chromosome numbers in S. polytrichoides sensu latiore in South Korea and adjacent areas. Localities of meiotically irregular collections are indicated by X. 1972 Chromosomes of Crassulaceae from Japan and South Korea 67

Table 1. Chromosome numbers of Crassulaceae from Japan and South Korea 68 Charles H. Uhl and Reid Moran Cytologia 37

Table 1. (Continued) 1972 Chromosomes of Crassulaceae from Japan and South Korea 69

Table 1. (Continued) 70 Charles H. Uhl and Reid Moran Cytologia 37

Table 1. (Continued) 1972 Chromosomes of Crassulaceae from Japan and South Korea 71

Table 1. (Continued) 72 Charles H. Uhl and Reid Moran Cytologia 37

Table 1. (Continued) 1972 Chromosomes of Crassulaceae from Japan and South Korea 73

Table 1. (Continued) 74 Charles H. Uhl and Reid Moran Cytologia 37

Table 1. (Continued) 1972 Chromosomes of Crassulaceae from Japan and South Korea 75

Nuclear volume

Besides chromosome number, several other parameters of nuclear cytology are potentially of interest to the student of classification and evolution. These include notably nuclear volume and mass, and the quantity of DNA associated with a chromosome set. Because of their different patterns of variation in chromosome number, the species studied here offer especially significant material for seeking correlations between these other parameters and chromosome number. Here we present a first crude attempt to correlate nuclear volume with chro

mosome number in two polymorphic and cytologically variable species complexes. The section Aizoon was chosen as an example of extensive eupolyploidy, from diploids

(n=16) to apparent heptaploids, and S. polytrichoides (sensu latiore) as an example of dysploidy, with gametic numbers from 11 to 35. In these two complexes the size of the sample and the proportionate difference in extremes of chromosome num ber are almost the same.

For estimates of nuclear volume, we used the same permanent squash prepara tions from which the chromosome numbers had been determined. Twelve micro

sporocyte nuclei (in most cases) at stages from pachytene through (mostly) diaki nesis were sketched with the aid of a camera lucida. Nuclei were chosen at random, except that conspicuously flattened or deformed nuclei were excluded. The mag

nification of the sketches was determined, and the volume of each nucleus was cal culated, using the formula for an ellipsoid: v=4/3 ƒÎ a2b, where v is the volume,

b is the longest semidiameter of the nucleus and a is the semidiameter at right angles to b. The thickness of the nucleus cannot be measured directly, and this method assumes that it is equal to the lesser of the two measured dimensions.

Any flattening of the nucleus will increase the two measured dimensions, and it will decrease the thickness while increasing the assumed value for the thickness.

Thus flattening will make the formula less nearly applicable and will increase the estimated volume. Since many if not most nuclei in these squash preparations

have been at least somewhat flattened, many if not most estimated volumes will be too large by unknown but sometimes probably substantial amounts. Flattening

of the nuclei unquestionably is a serious source, and probably the principal source, of error. It may be largely responsible for discrepancies among the estimated nuclear

volumes for different plants of the same species and with the same chromosome number, where the largest value is sometimes more than twice the smallest. To

reduce this error, we excluded the two most discrepant nuclear volumes of each twelve measured-usually the two largest, presumably representing the most

flattened nuclei-and calculated the mean from the remaining ten. Table 2 lists collections studied, with their chromosome numbers and the

estimates of their mean nuclear volume at late prophase I, with standard errors.

Figures 54 and 55 show mean nuclear volumes plotted against chromosome number

for about thirty collections of each of these two species complexes. In the first calculations, it seemed that variation within some plants and classes

was greater than expected, probably because too many flattened nuclei had been

measured. Accordingly, another set of measurements of nuclear volumes was made 76 Charles H. Uhl and Reid Moran Cytologia 37

Table 2. Chromosome number and nuclear volume in S. Sect. Aizoon (left) and S. polytrichoides sensu latiore (right) 1972 Chromosomes of Crassulaceae from Japan and South Korea 77

Fig. 54. Nuclear volumes at meiotic late prophase I in S. Sect. Aizoon compared with ploidy. Arrows indicate the means, the dotted arrows denoting the means before values for some collec tions (indicated by parentheses) were recalculated. See text for additional explanation. Note the approximately linear increase with ploidy. 78 Charles H. Uhl and Reid Moran Cytologia 37

for two diploid and three tetraploid collections of S. kamtschaticum, taking more care to exclude nuclei that had been excessively flattened in making the squash.

In Table 2 and Fig. 54 the earlier calculations for these collections are enclosed in parentheses. In Fig. 54 the collection numbers to the left of the vertical lines in dicate the recalculated volumes and the dotted and solid arrows indicate the means before and after recalculation, respectively. These recalculations support the conclusion that flattening is the major source of error in these measurements. Because this error is difficult to estimate but apparently is sometimes large, the individual values are not necessarily reliable. However, because the slides and measurements were made in the same way, and because of certain consistent trends in the results, it does seem that the aggregate of the measurements of all the collec tions provides a useful comparison. Comparison of nuclear volumes in the two species complexes at once reveals a striking difference between them. In Section Aizoon increase in chromosome num ber is accompanied by a nearly proportional increase in nuclear volume (Fig. 54).

Doubling the chromosome number from diploid to tetraploid approximately doubles the volume of the nucleus-on the average. The higher levels of ploidy do not all fit quite so well, but the trend is maintained. The extremes in calculated nuclear volume, from the lowest diploid (325ƒÊ3) to the highest heptaploid (1767ƒÊ3) differ by a factor of 5.4. In the highly dysploid S. polytrichoides (sensu latiore), on the other hand, no relation between chromosome number and nuclear volume is evident

(Fig. 55). The extremes of nuclear volumes (175 and 479ƒÊ3) differ by a factor of 2.7, but most of the range is found among plants of the same chromosome number, e. g., n=12.

These observations have important implications regarding the mechanisms by which chromosome number has changed with evolution in the two taxa. In Sec tion Aizoon the change in chromosome number seems clearly to be the result of multiplication of the more or less complete genome, implying a buffering and redundancy of genetic information proportional to the ploidy. In S. polytrichoides

(sensu latiore), on the other hand, most plants appear to be effectively diploid, since the average nuclear volumes do not differ any more among plants with chro mosome numbers ranging from n=12 to n=27 than they do just among plants with n=12. (The one plant with n=35 has somewhat larger nuclei.) It appears that very extensive rearrangement and repackaging of essentially the same amount and kind of chromosomal material, probably chiefly by translocations, have accompanied and made possible the many changes in chromosome number in this complex. Com parable dysploid differences in chromosome number among species within a genus have been reported in certain plants (e. g., in Carex by Davies 1956) and animals

(e. g., in moths by Suomalainen 1965), where diffuse kinetochores of the chromosomes are thought to have made them possible. There is no evidence for diffuse kineto chores in S. polytrichoides, and we doubt their presence in the Crassulaceae. Clearly nuclear volume is a significant cytological parameter. Further studies are justified, using nuclei that have not been flattened and for which more accurate calculations can be made. Fig. 55. Nuclear volumes at meiotic late prophase I in S. polytrichoides (sensu latiore) compared with gametic chromosome number. Chromosome numbers were estimated for meiotically irregular collections, indicated by parentheses. Note the absence of any clear correlation. Several means are indicated by arrows. 80 Charles H. Uhl and Reid Moran Cytologia 37

Summary

Chromosome numbers are reported for 257 collections, representing all but about five of the approximately 35 species of Crassulaceae native to Japan and South Korea, 21 of them for the first time. These species differ considerably among themselves in their chromosomes: in number, in size, and in the constancy or variation within species. A higher proportion of triploids and other odd-ploids has been found than is known in the family elsewhere, usually accompanied by obvious adaptations for vegetative propagation. Several species or species com plexes that vary greatly in their morphology have been found to vary also in their chromosomes; but not enough is known about them yet to propose new ways of classifying them. Rough measurements of nuclear volume support the conclusion that members of two species complexes differ in the types of chromosome change predominating in their evolution, polyploidy in S. Sect. Aizoon and structural chromosomal rearrangements in S. polytrichoides sensu latiore.

Acknowledgement

We thank the University of California Botanical Garden, Berkeley, and par ticularly Mr. Paul C. Hutchison, for their cooperation in receiving, growing and distributing many of the plants reported here.

Literature cited

Baldwin, J. T., Jr. 1937. The cyto- of the Telephium Section of Sedum. Am. J. Bot. 24: 126-132. Berger, A. 1930. Crassulaceae. Die Naturlichen Pflanzenfamilien. A. Engler and K. Prantl, editors. Second edition 18a: 352-483. Chong, T. 1957. Korean Flora. Seoul. Davies, E. W. 1956. Cytology, evolution and origin of the aneuploid series in the genus Carex. Hereditas 42: 349-365. Jinno, T. 1956. On the relation between the chromosome numbers and the flora growing on the coast of the Inland Sea in Japan. Jap. J. Gen. 31: 147-150. Moran, R. 1964. Sedum spectabile in South Korea. Cactus and Succulent J. Am. 36: 140 -144. - 1965. Sedum viridescens Nakai. Cactus and Succulent J. Am. 37: 5-8. Nakai, T. 1940. Notulae ad Plantae Asiae Orientalis (XII). Jour. Jap. Bot. 16: 7-8. Ohwi, J. 1965. Flora of Japan (in English). Edited by F. G. Meyer and E. H. Walker. Smith sonian Institution, Washington, D. C. Soeda, T. 1944. A cytological study on the genus Sedum, with remarks on the chromosome num bers of some related plants. J. Fac. Sci. Hokkaido Imp. Univ., Series V, 3: 221-231. Sugiura, T. 1936. Studies on the chromosome numbers in higher plants... I. Cytologia 7: 544-595. - 1937. A list of chromosome numbers in Angiospermous plants III. Bot. Mag. (Tokyo) 51: 425-426. Suomalainen, E. 1965. On the chromosomes of the Geometrid moth genus Cidaria. Chromosoma 16: 166-184. Turesson, G. 1938. Chromosome stability in Linnean species. Ann. Roy. Agr. College Sweden 5: 405-416. 1972 Chromosomes of Crassulaceae from Japan and South Korea 81

Uhl, C. H. 1952. Heteroploidy in Sedum rosea. Evolution 6: 81-86. - 1961. Some cytotaxonomic problems in the Crassulaceae. Evolution 15: 375-377. - 1963. Chromosomes and phylogeny of the Crassulaceae. Cactus and Succulent J. Amer. 35: 80-84. - and Moran, R. 1953. The cytotaxonomy of Dudleya and Hasseanthus. Am. J. Bot. 40: 492-502.

Note added in proof: Five months after this paper was submitted, we learned of a thesis on Japanese species of Sedum done in 1967 by Hiroshi Yuasa and saw excerpts from the Japanese Encyclopedia of Horticulture (in Japanese), vol. 4, 1969, and vol. 5, 1970, in which some of his chromosome numbers in Orostachys and Sedum are published. Many of his counts agree with ours, but some do not; and he studied some species which we did not.