ANALYSIS OF THE KARYOTYPES IN YUCCA, A GA VE AND THE RELATED GENERA WITH SPECIAL REFERENCE TO THE PHYLOGENETIC SIGNIFICANCEI~ Dyuhei SATo Divisionof Genetics, Bot. Inst. Faculty of Science, Tokyo Imperial University McKelvey and Sax (2933) have called attention to the existence of taxonomic and cytological similarities of the genera Yucca, Hesperoyucca, Gleistvucca,Hesperoaloe and Samuela of the Liliaceae with the genera Agave and Fourcroya which belong to a related family, Amaryllidaceae. Wh.itaker (1934) also has reported that Polianhes and Fourcroya have exactly the same chromosome constitution as the Yucca-Abave karyotype (5 long and 25 short chromosomes) (Figs. 1, 2). These observations when considered in respect to taxonomic resemblances, seem to indicate that the genera mentioned above are more closely related than it is shown by their classifica- tion into distinct families. Whitaker also has remarked that Dasylirion (2n=38) and ATolina(2n=36) in Yucceae and Doryanthes (2n=36) in Agavoideae are of different karyotypes from the Yucca-Agave type. In the present work an analysis of the karyotypes in Liliaceous plants has been attempted and several karyotypes have been found in Scilloideae. Eucornis and Carassia have been selected with the purpose of discovering a possible connecting link between these genera and the Yucca-Agave group. In the present paper an analysis of the karyotypes of the following species is given. LILIACEAE Scilloideae 211 Fig. Euconis undulata 60=8L+8M+44S (4b)2) 3 Euconsispallidi ora 60=8L+8M+44S (4b) 4 Eucomispunctata 60=8L±8M+44S (4b) 5 Camassiaescrema 30=6L+24S (2b) 6 Yucceae Yuccafilamentosa 30 60=1OL+50S (2b) 1, 7 Yuccarecurvifolia 30 60=1OL+50S (2b) 2, 8 Yuccaaloifolia 60=1OL+50S (2b) 9 „ var. albo-marginata 60=10L+50S (2h) 10 1) Contributionsfrom the Divisionsof Plant-Morphologyand of Genetics,Botanical Institute Faculty of Science,Tokyo Imperial University,No, 154. 2) b=basis (cf. Sinoto 1929),L=long, M=medium, S= small. THE JAPANESE JOURNAL OF GENETICS, VOL. XI, NO. 5, NOV., 1935 273 Dasylirion texanum 38 (2b) 11 Dasylirion wheeleri 38 (2b) 12 Dracaeneae Dracaena terminalis var. Ii 38 (2b) 13 Dracaena conJesta ca. 114 (6b) Dracaena cannaefolia ca. 114 (6b) AMARYLLIDACEAE Agavoideae Ag ave vivipara 60=1OL+50S (2b) 18 Ag ave lutea var. heterocentra 60=10L+50S (2b) 17 Agave americana 120=20L+1005 (4b) 20 var. albo-marcinata 120= 20L+ 1005 (4b) 21 (240=40L+300S) (8b) 22 var. variegata 120= 20L+ 1005 (4b) Agave Saisalana 150= 25L+ 1255 (5b) 23 (A,;ave ?) sp. A 60 =10L+ 50S (2b) ,, B 60=1OL+50S (2b) ,, c 120=20L+100S (4b) D 120=20L+1005 (4b) Fourcroya bidantea 60=1OL+50S (2b) 14 Fourcaoya pubesens 60=1OL+50S (2b) 15 Beschorneria tubfioi a 60=10L+50S (2b) 16 Polianthes tuberosa (lore-plena 60=1OL+50S (2b) OBSERVATION The materials used;ed were all obtained frofrom pot plants cultivated in the Koishikawa Botanic Garden of the Tokyo hImperial University. The root- tips were fixed in Karpechenko'srpechenko's solution and the sections were cut twenty micra in thickness. The pollen mother cells \were fixed in solutions such as Karpechenko's, Bouin'sis and Allen's modificaticmodification of Bouin's fluid. The sections were cut from twelve to twenty micra in thicknthickness. The sections of both root- tips and pollen motherr cells were stained by NNewton's gentian-violet method. Scilloideae. Eucornis'corms undulata (Fig. 3), E pallidiflora (Fig. 4) and E. puirctata (Fig. 5) are of the same karyotypes, they have namely eight long, eight medium and fourty-foururty-four short chromosochromosomes. The long chromosomes have terminal spindle fiber attachments and tthe medium chromosomes have terminal or extremelyly subterminal ones. IiIn this respect these long and medium chromosomesyes resemble long chrorchromosomes of the Yucca-Agave group though the chromosomelromosome lengths of tithe former are longer than the latter. Four short chromosomes show a characteristic form in having satellites as in Scilla peruviana (cf. Sato, 1934,193, 1935). From this observa- tion and that of Koerperich~erperich (1930) in EiiccEiicomis undulata (2n = 30), these plants seem to be tetraploidraploid or tetrabasic planplants (4b). 274 Sato-Analysis of the Karyotypes in Yucca, Agave Camassia escyenta (Fig. 6) has thirty chromosomes, i.e. six long and twenty-four short ones. The pronounced heteromorphism of this species is to be compared with the Yucca-Abave karyotype though the long chromo- Fig. 1. First metaphase of meiosis of pollen mother cell in Yuccafalamentosa (n=3o). Fig. 2. Yuccarecurvifolia (n= 3o). 2900X Fig. 3=13. Somatic metaphasesfrom root-tip cells of i i forms in Liliaceae. Fig. 3. Eucomisundulata (2n=6o). Fig. 4. E. ~allidflora (2n=6o). Fig. 3-5. ca. 1450. Fig. 8. Y. securvifolia(2n=6o). Fig. 9. Y. aloifolia (2n=6o). Fig. io. Y. aloifolia var. alho-ma;inata (2n = 60). Fig. i I. Dasylirion texanum (2n = 38). Fig. 12. Das. wheeleri (an=38). Fig, 13. Draeanea terminalis var. ti (2n=38). Fig. 6-i3. ea. 2200X THE JAPANESE JOURNAL OF GENETICS, VOL. XI, NO. 5, NOV., 1935 275 somes have submedian spindle fiber attachments. Yucceae. Yuccafilamentosa (Fig. i) and Y, recurz'ifolia(Fig. 2) have five long and twenty-five short bivalents in the meiotic metaphase. In the somatic cells of Y.filamentosa (Fig. 7), Y. recurvifolia (Fig. 8), Y. aloifolia (Fig. g) and Y. aloifolia, var. albo-marginata (Fig. I o) there are found ten long Fig. 14-23. Somaticmetaphases from root-tip cells of io forms in Agavoideae. Fig. 14. Fonrcruya gigantea (2n = 60). Fig. 15. P. pubesens (2n = 60). Fig, i6. Beschorneriahibflora (2n = 60). Fig, 17. Agave lntea var. heterocentra(2n=6o). Fig. i8. A. vivipara (20=60). Fig. 19. Agave sp. A (2n=60). Fig. 20. A. americana (2n= 120). Fig. 2i. A. americana var. albo-mar,;inata (2n=120). Fig. 22. Somatic doubling of chromosomesin A. americana var. albo-marginata (2n =236[24o]). Fig. 23. A. Saisalana (2n= 147[15o]). ca. 2200X 276 Sato-Analysis of the Karyotypes in Yucca, Agave chromosomes and fifty short ones. The long chromosomes have terminal (or extremely subterminal) spindle fiber attachments. Dasylirion teaxanum (Fig. II) and Das. wheeleri (Fig. i2) have thirty- eight chromosomes, several long chromosomes of which have submedian constrictions. These long chromosomes resemble those of Cainassia escrenta. The existence of two satellited chromosomes in Das. texanum proves that this species is diploid or a dibasic plant (2b). Dracaeneae. Dracaena terminalis var. ti (Fig. 13) has thirty-eight chromosomes, the long chromosomes of which have submedian spindle fiber attachments. The karyotype of Dracaena resembles that of Dasylirion and Camassia, though all the chromosomes are smaller than those of the latter two as a whole. Dra. tong esta and Bra. cannaefolia have more than hundred chromosomes and seem to be hexaploids or hexabasic plants (6b). Agavoideae. Agave vivipara (Fig. i8) and A. lutea var. heterocentra (Fig. 17) have sixty chromosomes and A. americana (Fig. 20), A. americana var. albomarginata (Fig. 2 i) and var. variegate have one hundred and twenty chromosomes. The former two species are dibasic plants (2b) and the latter are tetrabasic (4b). The somatic doubling of chromosomes was observed in A. americana var. alto-marg inata and the chromosome numbers counted were 236=38L+ 1985 (Fig. 22), 226=4oL+ 186S and so on. These numbers seem to be derived from the true original number 240= 4oL + 2005 (8b) which may be octoploid. A. Saisalana have twenty-five long chromsomes and more than hundred small chromosomes, for example 25L -F122S= 147 (Fig. 23), 25L+ I I6S= 141 and so on. This species appears to be 25L+ I25S=150 (5b) and a pentabasic plant. Unknown species which perhaps belong to the genus Agave also have the same karyotype mentioned above. A has the leaf with a white margin, B has the leaf with a white spines and a white line in the midrib, the leaf of C has white spines alone and that of D has a white line in the midrib. A and B have sixty-chromosomes and are dibasic plants. C and D have one hundred and twenty chromosomes and are tetrabasic plants. Foirrcroya gigantea, F. pubescens, polianthes tuberosa ftorepleno and Beschorneria tubiflora have sixty chromosomes and the same karyotypes found in the Yucca-Agave group. DISCUSSION The previous workers, Muller (1912), Heitz (1926), Koerperich (1930), McKelvey and Sax (1933) and Whitaker (1934) have reported on the chro- mosome constitutions in Eucomis, Yucca, Hesperoyucca, Hesperoaloe} THE JAPANESE JOURNAL OF GENETICS, VOL. XI, NO. 5, NOV., 1935 277 Samuela, Nolina, Dasylirion, Dracaena, Agave, Fourcroya, Polianthes, Beschorneriaand Doryanthes. Yucca, Hesperoyucca, Hesperoaloe and Samuela in Yucceae and Agave, Fourcroya, Polianthes and Beschorneria in Agavoideae have the same karyo- types, so-called Vucca-Agavetype (5L + 25S). The present observation of the polyploidy in Agave suggests that this Yucca-Agavetype is a very stable karyotype. Dasylirion and Nolina in Yucceae have other karyotypes which resemble those of Dracaena in Dracaeneae, and Doryanthes in Agavoideae, par- ticularly in the fact that these karyotypes have the long chromosomes with the submedian spindle fiber attachments. We can easily be convinced that the karyotypes of Yucca, Agave, Fourcroya and Beschorneria do not present an accidental coincidence only based on the cytological observations mentioned above. The present results of observations support that "five genera of the Liliaeeae (Hesperoatoe,Flesperoyrcca, Cleistoyucca, Yucca, Sar;ruela) and four genera of Amaryllidaeeae (Fourcroya, Agave, Beschorneria, Polianthes), which, on distributional, taxonomic, and cytological grounds, are closely akin to each other," and "these facts should be given serious consideration in any taxonomic revision of these two families where an attempt is made to arrange the genera in a phylogenetic series." (cf. Whitaker 1934 p. 140).