Saravanakumar. K, Cytotaxonomical and Karyomorphological Studies in some Aquatic Members of , Int.J.Curr.Biotechnol., 2013, 1(7):11-17.

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Cytotaxonomical and Karyomorphological Studies in some Aquatic Members of Commelinaceae

Saravanakumar. K* Botany Wing-DDE, Annamalai University, Tamilnadu, India -608002.

ARTICLE INF O ABSTRACT The study was carried out to clarify karyologically a part of the speciation system in Commelinaceae. There are very few karylogical studies recorded earlier but the Article History: intraspecific structure has not been clarified karyologically, though the chromo- Received 12 September 2013 some number variable within the species. The genus Amischophacelus is repre- Received in revised form 14 September 2013 sented by only two species namely A. axillaris and A.cucullata and both are distin- Accepted 20 September 2013 guished by the presence of cucullate leaf sheath and seed characters. The genus Commelina is readily distinguished from other genera by means of its foliaceous Available online 28 September 2013 bracts. In general this genus is a distinct one with several complexes. The chromo- somes are mainly of medium size with mostly sub-median primary constrictions. In this respect it has close similarity with Murdannia where a dominant line of x = 10 is indicated. The aim of the present study is to supply further karyological information about aquatic members of Commelinaceae. Not only the genera differ among themselves in possessing various types of chromosomes in various combi- Key words: nations but also different species of a particular genus and even the varieties of Cytotaxonomy,Karyomorphology, a particular species possess distinct karyotypes of chromosomes. Based on the Aquatic , Commelinaceae. present study, morphological and karyological characters there are two cytotaxonomical groups have been formed, they are, Group I (Amischophacelus axillaris and A. cucullata) and group II (Commelina diffusa, C. diffusa ssp. aquatica) and M. nudiflora).

Introduction Materials and Methods The family Commelinaceae is commonly known as Spiderwort family. It comprises about 37 genera and The species 1.Amischophacelus axillaris, 2. A. 600 species. The family members are widely distributed cucullata, 3. Commelina diffusa, 4. C. diffusa ssp. aquatica in tropical and subtropical regions of the world and and 5. Murdannia nudiflora were collected at the extend to temperate regions. It has three major centers seedling stage (5cm length) and allowed to grow in of taxonomic diversity namely 1.Tropical , 2. earthen pots in the Botanical Garden of the Annamalai Mexico and Northern and 3. The Indian University. For mitosis, root tip squash was made from subcontinent. Only 6 genera (Aneilema, Buforrestia, the excised root tips collected from potted plants Commelina, , Murdannia and Pollia) are between 9.30 a.m. and 11.30 a.m. and thoroughly indigenous species in both the New world and Old world washed in running water to remove the sand. They were (Faden,1978). In Tamilnadu State of India, most of the pre-treated in 0.002m 8-Hydroxyquinoline at 40 C for 3 members are found as weeds in cultivated field and hours. Then, the root tips were cleanly washed in few taxa grow as wild species in lower elevations as distilled water and fixed in Carnoy’s Fluid (1:3 acetic well as temperate regions of Eastern and Western Ghats. acid: ethyl alcohol) mixture for 24 hours. Among the species of Commelinaceae available in Again, the root tips were washed in distilled water. Then Tamilnadu only some of the taxa have been the root tip squashes were prepared following iron cytologically investigated so far. Even though the alum haematoxylin squash technique (Marimuthu and chromosome numbers were known, the morphology of Subramaniam, 1960). Observations were made by using the chromosomes has not been studied in detail in most Meiji RM-T Trinocular light microscope with the of the species. The present study was undertaken on magnification of X 1250 with an eyepiece lens (12.5x) the members available in Cuddalore District of Tamil and an objectives of oil immersion lens (100x). The nadu in order to understand the cytological characters important plates were microphotographed. For the of the family. assessment of the number and morphology of chromosomes, ten metaphase plates in each species were studied. Measurement of all the chromosomes in *Corresponding author. a complement was recorded and the homologous Email address: [email protected]

11 Int.J.Curr.Biotechnol. Volume 1; Issue 7; Sep, 2013 chromosomes were paired and arranged in decreasing fusiform at apex, naked. Fruits capsule oblong, order of length. Idiograms were made in decreasing ellipsoid, beaked, shortly stipitate pointed end at the order of length. tip without any depression. Seeds oblong, compressed, truncate at the base, apex rounded, dark brown shining. The observation of somatic chromosomes at metaphase were arranged and classified based on the centromeric 3. Commelina diffusa Burm. F. positions of each homologous pairs and individual Antals clawed, anterior not clawed. Stamens 6, of 3 chromosome in case of heterologous were arranged fertile anterior, 3 staminodes posterior; filaments pale according to Levan et al., (1964). Karyotype asymmetry violet, slender; anthers small. Ovary 3-celled, of which has been estimated using the equation of Huziwara two 2-ovulate, the third 1-ovulate. Fruits capsule 5- (1962). seeded, oblong, acuminate and coriaceous. Seeds oblong, cylindric, tuberculate or reticulate brown. Morphological Observations 4. Commelina diffusa ssp. aquatica Morton 1. Amischophacelus axillaris (L.) R. Rao et Kamm. Annused; peduncles longer, equalling or exceeding the Annual, suberect. Root fibrous. Stem stout or slender, spathe. Flowers borne on exceptionally long pedicels; diffusely branched, branches creeping below, glabrous sepals 3, anterior-2 broadly ovate, jointed at the base or sparsely hairy, often coloured, internodes long. and posterior –1 boat shaped; petals 3, large rich blue Leaves sessile, narrowly linear to linear lanceolate, in colour. Stamens 3, staminodes 3; filaments slender; acute or acuminate, flat, glabrous or hairy; sheath anthers small and blackish margin. Ovary 2-celled of inflated, ciliate. Inflorescence in cymes reduced to which two are 2-ovulate and third one 1-ovulate. Fruits axillary fascicle. Flowers with small linear bracteoles, capsule 5-seeded, oblong and acuminate. Seeds oblong, almost concealed in the leaf sheaths; sepals 3, cylindric, tuberculate, brown. spathulate, lanceolate, acuminate; petals 3, pink-blue or rose purple; filaments fusiform, bearded; style 5. Murdannia nudiflora (L.) Brenan fusiform at apex, naked. Fruits capsule oblong, Annual, erect. Root fusiform, thick and tuberous. Stem ellipsoid, beaked, shortly stipitate pointed end at the glabrous with long internodes. Leaves radical, linear, tip without any depression. Seeds oblong, compressed, finely acuminate, flat, striate, narrowed into a short or truncate at the base, apex rounded, dark brown shining. long sheath. Inflorescence in terminal panicles, stout, sparingly branched; Flowers bisexual, actinomorphic, 2. Amischophacelus cucullata (Roth) R. Rao et Kamm. bracts caducous; sepals 3, free, ovate, oblong, acute, concave; petals 3, equal pale purplish blue, Annual, suberect. Root fibrous. Stem stout or slender, suborbicular. Stamens 6, of 3 fertile and 3 sterile; diffusely branched, branches creeping below, glabrous filaments all equal, bearded. Ovary sessile, 3-cells or sparsely hairy, often coloured, internodes long. each cell 2-ovulate; style naked. Fruits capsule ellipsoid, Leaves sessile, narrowly linear to linear lanceolate, mucronate, the cells 2-seeded, and valves hard. Seeds acute or acuminate, flat, glabrous or hairy; sheath 2 per cell, rough or echinulate, brown and faintly pitted. inflated, ciliate. Inflorescence in cymes reduced to axillary fascicle. Flowers with small linear bracteoles, Cytological Observations almost concealed inthe leaf sheaths; sepals 3, 1. Amischophacelus axillaris (L.) R. Rao et Kamm. (2n spathulate, lanceolate,acuminate; petals 3, pink-blue = 20) or rose purple; filaments fusiform, bearded; style The diploid chromosome number 2n = 20 (PLATE – 1, Fig –1) has been observed in the somatic cells. The detailed Table -1. Karyological features of Amischophacelus axillaris Number of Chromosome length in µm homologous Long Short Total Arm Relative Centro Position of chromosom arm arm length ratio length mere centromer e pairs L/S index e 1 5.0 1.3 6.5 3.8 6.46 20.00 st 2 4.0 1.8 6.0 2.2 5.96 30.00 sm 2 3.8 1.5 5.5 2.5 5.46 27.27 sm 2 2.7 2.3 5.2 1.1 5.16 44.23 m 2 2.5 1.2 3.9 2.0 3.87 30.76 st 1 2.0 0.4 2.6 5.0 2.58 15.38 t Total chromosome length = 100.6 µm Total form percentage = 31.21 Absolute chromosome length = 50.3 µm Total frequency % = 44.84 Average chromosome length = 5.03 µm Disparity index = 266.1 Karyotype formula = 4 m + 8 sm + 6 st + 2t Volume 1; Issue 7; Sep, 2013 Int.J.Curr.Biotechnol. 12 Table – 2. Karyological features of Amischophacelus cucullata Number of Chromosome length in µm Centromere Position of homologous Long Short Total length Arm ratio L/S Relative index centromere chromosome arm arm length pairs 2 4.5 1.5 6.2 3.0 5.98 24.19 st 1 4.0 1.8 6.0 2.2 5.78 30.00 st 3 3.0 1.8 5.0 1.6 4.81 36.00 sm 2 3.0 0.8 4.0 3.7 3.86 20.00 st 2 2.8 0.6 3.6 4.6 3.47 16.66 st 1 2.6 0.4 3.2 6.5 3.08 12.50 t Total chromosome length = 103.6 µm Total form percentage = 25.86 Absolute chromosome length = 51.8 µm Total frequency % = 37.01 Average chromosome length = 4.70 µm Disparity index = 325.68 Karyotype formula = 6m + 14st + 2t karyomorphological features are furnished in the table- noticed. The calculated values of total frequency 1. Most of the chromosomes are having submedian percentage (74.17%) and total form percentage (47.31%) constrictions. The length of the chromosome ranges are also furnished. from 6.5 µm to 2.6 µm. The total chromosome length (100.6 µm) and absolute chromosome length (50.3 µm) 5. Murdannia nudiflora (L.) Brenan (2n = 22) are calculated. The values of total frequency (44.84 %) The diploid chromosome number 2n = 22 (PLATE -1; Fig- and total form percentage (31.21%) are furnished. 5) has been observed. The details of Broken anaphase has also been observed (PLATE-1, Fig- karyomorphological features are furnished in the table- 6). 5. Most of the chromosomes are having submedian constrictions. The chromosome length ranges from 4.7 2. Amischophacelus cucullata (Roth) R. Rao et Kamm. mm to 2.8 mm. The total chromosome length (75.2 mm) (2n = 22) and absolute chromosome length (37.6 mm) are The somatic chromosome number 2n = 22 (PLATE-1, Fig furnished. The values of total frequency percentage - 2) has been observed in the somatic cells. The detailed (56.07%) and total form percentage (31.91%) are karyomorphological features are furnished in the table calculated. Multinucleate stage has also been observed – 2. Most of the chromosomes are having subterminal (PLATE- 1, Fig -7). constrictions. The length of the chromosome ranges from 6.2 µm to 3.2 µm. The total chromosome length (103.6 µm) and absolute chromosome length (51.8 µm) Results and Discussion are furnished. The calculated values of total frequency and total form percentage were (37.01 %) and (25.86%) The present report of Amischophacelus axillaris 2n = 20 respectively. correlates with early report as 2n = 20 by Raghavan and Rao (1961), Kammathy and Rao (1961b), Shetty 3. Commelina diffusa Burm. f. (2n = 30) and Subramanyam (1961), Rao et al., (1970), There are 2n = 30 chromosomes in the somatic cells of Bhattacharya (1975), Malla et al., (1978a), Alam et al., this species. (PLATE - 1, Fig - 3). The karyomorphological (1984) Bai et al., (1984) and Renuga devi and analysis is given in the table -3. Most of the Sampathkumar (1983 and 1986). chromosomes are submedian. The length of the chromosome ranges from 4.3 µm to 3.5 µm. The total Amischophacelus cuculata shows in present finding (2n chromosome length (118.4 µm) and absolute = 22) deviates from the previous report 2n = 20 reported chromosome length (59.2 µm) are furnished. The by Kammathy and Rao (1961 b), Raghavan and Rao calculated values of total frequency percentage (1961) and Shetty and Subramanyam (1962), Rao et al., (66.29%) and total form percentage (32.09%) are (1970), Bai et al., (1984), and Renuga devi and furnished. Sampathkumar (1986).

4. Commelina diffusa ssp. aquatica Morton (2n = 28) The present chromosome report of Commelina diffusa The somatic chromosome number 2n = 28 (PLATE -1, is similar to that of previous reports (2n = 30) by Fig- 4) has been observed in the species. The Simmonds (1954), Raghavan et al., (1961), Kammathy karyomorphological features are furnished in the table- et al., (1961a), Morton (1967), Lewis et al., (1964,1967), 4. The chromosome length ranges from 6.0 µm to 3.5 Kammathy et al., (1964), Bhattacharya (1975), Faden µm. The total chromosome length (104.4 µm) and its (1980), Alam et al., (1984), Patwary et al., (1987), absolute chromosome length (52.2 µm) have been

13 Int.J.Curr.Biotechnol. Volume 1; Issue 7; Sep, 2013 Table – 3. Karyological features of Commelina diffusa Num ber of Chromosome length in µm homologous Centro mere Position of Lon g Short arm Total Arm ratio Relative chromosome Index centromere arm length L/S leng th pairs

1 3.3 0.6 3.8 5.0 3.20 15.78 st 4 2.8 0.8 3.5 3.5 2.29 21.05 st 2 2.5 1.6 4.3 1.5 3.63 37.20 sm 5 2.0 1.2 3.8 2.0 3.20 31.57 sm

3 2.0 2.0 4.2 1.0 3.54 47.61 M T otal chromosome length = 118.4 µ m Total form percentage = 32.09 Absolute chromosome length = 59.2 µm Total frequency % = 66.29 Average chromosome length = 3.94 µm Disparity index = 383.41 Karyotype formula = 6M + 14sm + 10st Table – 4. Karyological features of Commelina diffusa ssp. aquatica

Chromosome length in µm N umber of Centrom ere homologous Long S hort Total Arm R elativ e Index Position of chr omosom e arm arm length ratio length centromere pairs L/S 1 3.3 2.5 6.0 1.3 5.74 41.66 sm

1 3.2 0.8 4.2 4.0 4.02 19.04 st

4 2.5 1.6 4.3 1.5 4.11 37.20 sm

2 2.4 2.2 4.8 1.0 4.59 45.83 m

4 2.0 2.0 4.2 1.0 4.59 47.91 M

2 2.0 1.3 3.5 1.5 3.35 37.14 sm

Total chromosome length = 104.4 µm Total form percentage = 47.31 Absolute chromosome length = 52.2 µm Total frequency % = 74.17 Average chromosome length = 3.72 µm Disparity index = 380.00 Karyotype formula = 8M + 4m + 14sm + 2st

Volume 1; Issue 7; Sep, 2013 Int.J.Curr.Biotechnol. 14 Table – 5. Karyological features of Murdannia nodiflora N um be r of Chromosome length in µm

homologous Long S hort T otal Arm R elative Ce ntrom ere Position of chromosome arm arm le ngth ra tio le ngth ind ex ce ntrom e re pa irs L/S 1 3.0 1.5 4 .7 2 .0 6 .25 31 .91 sm 2 2.6 1.3 4 .1 2 .0 5 .45 31 .70 sm

3 2.4 0.6 3 .2 4 .0 4 .25 18 .75 st 1 2.3 1.0 3 .5 2 .3 4 .65 21 .51 sm 1 2.0 0.8 3 .0 2 .5 3 .98 26 .66 sm 1 1.6 1.4 3 .2 1 .1 4 .25 43 .75 m

2 1.3 1.3 2 .8 1 .0 3 .72 46 .42 M

Total chromosome length = 7 5.2 m Total form percentage = 3 1.91

Absolute chromosome length = 3 7.6 m Total frequency % = 5 6.07 Average chromosome length = 3 .4 1 m Disparity index = 2 84 .1 0 Ka ryoty pe form ula = 4M + 2m + 10sm + 6st

Fujishima, (1982), Zheng et al., (1989), Palomino et al., (1990), Umoh et al., (1991), Cristobal de Hinojo et al., The genus Commelina is readily distinguished from (1998 and 2004), Pitrez (2001) and Grabiele (2005) other genera by means of its foliaceous bracts. In have reported the chromosome number of Commelina general this genus is a distinct one with several diffusa to be 2n = 30 reported. In Commelina diffusa complexes. The chromosomes are mainly of medium subsp. aquatica the diploid chromosome number is 2n size with mostly sub-median primary constrictions. =28 and 30 studied by Morton(1967) and Bhatt (1976) Most of the species show n = 15 or its multiples of for African populations of the species and Umoh (1993). chromosome numbers. The diploid forms of Commelina diffusa (2n = 28 and 30) have been found in tropical The observed chromosome number (2n=22) of regions. Murdannia nudiflora correlates with the previous report by Rao et al., (1960) and Panigrahi and Kammathy A basic number of x = 15 chromosomes which is (1963) and they observed 2n = 22 chromosomes in this secondarily derived is indicated for Commelina where species. polyploidy have played a major role in evolution and intraspecific aneuploidy is of minor significance. In The morphology of chromosomes are shown in this respect it has close similarity with Murdannia Idiograms (Fig. – 1 to 5) The ‘M’ and ‘m’ types of where a dominant line of x = 10 is indicated. In both the chromosomes represent symmetrical and primitive genera inter and interspecific polyploidy are far more karyotypes. The ‘sm’, ‘st’ and ‘t’ chromosomes represent common than intraspecific aneuploidy. Though the asymmetrical and advanced karyotypes. But these types basic numbers differs (x = 15 in Commelina and x = 10 are comparatively lesser in number in all the species in Murdannia) a prototype of x = 5 is suggested in both studied, when compared to ‘sm’, ‘st’ and ‘t’ types of the genera. The secondary basic number of x = 11 is chromosomes. Therefore, asymmetrical karyotypes are indicated in a few species of Murdannia and these prevalent in all the species of Commelinaceae studied. might have been secondarily derived from x = 5 or x = According to guideline (number 3, Karyotypes 10. So these two genera are closely related and containing metacentric chromosomes of uniform size considered to form another group. are likely to be found in less derived plants than those with acro or telocentric chromosomes of unequal size), Based on the present study, morphological and the species of commelinaceae may be considered as cytological characters different cytotaxonomical more evolved as evidenced by the study of morphology groups have been formed. They are, of chromosomes. Not only different genera but also various species of a genus and even the varieties of a 1.Group – I – Amischophacelus axillaris and A. cucullata. particular species differ among themselves in having 2. Group – II – one species and one sub species of different types of chromosomes in various Commelina namely (C. diffusa, C. diffusa ssp. aquatica) combinations. and one species of Murdannia (M. nudiflora)

The genus Amischophacelus is represented by only two Not only the genera differ among themselves in species namely A. axillaris and A.cucullata and both possessing various types of chromosomes in various are distinguished by the presence of cucullate leaf combinations but also different species of a particular sheath and seed characters. A few flowered sessile cyme genus and even the varieties of a particular species is concealed within the leaf axils within conspicuous possess distinct karyotypes of chromosomes. Therefore bracts and bracteoles and it has the basic chromosome it is concluded that aneuploidy, autopolyploidy, number, x = n = 10 and there two species are considered allopolyploidy and structural alterations of to form a separate group.

15 Int.J.Curr.Biotechnol. Volume 1; Issue 7; Sep, 2013 chromosomes among various species studied play a Cristobal de Hinojo, M. E., González Villarreal, L. M. important role in the origin and evolution of the species and Frías de Fernández, A. M. 1998. Estudios of aquatic members of Commelinaceae. citogenéticos en el género Commelina L. (Commelinaceae). I. Análisis cariotípico de Commelina References erecta L. Y Commelina diffusa Burm. Lilloa, 39(2): 157– 164. Alam, N., and Sharma, A.K., 1984. Trends of chromosome Cristobal, M. E., Caro Caro, M. S., González Villarreal, L. evolution in family Commelinaceae. The Nucleus, 27(3): M. and A. M. Frias. 2004. Estudios citogenéticos en el 231 – 241. género Commelina (Commelinaceae). II Análisis Bai, L., Kuriachan, P. I. and Ninan, C. A. 1984. meiótico en Commelina erecta L. Y Commelina diffusa Chromosome Number Reports LXXXII. Taxon, 33: 126– Burm. Lilloa, 41(1–2): 23–27. 134. Faden, R. B. and Suda,Y. 1980. Cytotaxonomy of Bhatt, R. P. 1976. In IOPB chromosome number reports Commelinaceae: chromosome counts of some African LIII. Taxon, 25: 483–500. and Asiatic species. Bot. J. Linn. Soc. 81: 301–325. Bhattacharya, B., 1975. Cytological studies on some Fujishima, H. 1982. Chromosome numbers of Indian members of Commelinaceae. Cytologia, 40(2): Commelina auriculata Blume and C. diffusa Burm.f from 285 – 299. Japan. Chromosome Inf. Serv. 33: 23–24. Bhattacharya, G. N. 1975. Chromosomes in Lagenandra Grabiele, M. 2005. Chromosomes of four species of ovata (L.) Thw. (Araceae). Proc. Indian Sci. Congr. Assoc. Commelina (Commelinaceae). Bot. J. Linn. Soc. 148: 207– 62: 129. 218.

Volume 1; Issue 7; Sep, 2013 Int.J.Curr.Biotechnol. 16 Huziwara, Y. 1962. Karyotype analysis in some genera 363–368 in D. Hong (editor), Plant Chromosome of Compositae VIII. Further studies on the chromosomes Research 1987. of Aster. Amer. J. Bot. 49: 116 – 119. Kammathy, R.V., and Rao, R.S., 1961a. Notes on Indian Commelinaceae. II Cytological observation. Bull. Bot. Sur. India, 3: 167 – 169. Kammathy, R.V., and Rao, R.S., 1964. Notes on Indian Commelinaceae. IV. Cytotaxonomic observations. Bull. Bot. Surv. India, 6: 1. Kammathy, R.V., Rao. R.S., 1961b. Notes on Indian Commelinaceae. III. Cytological observations. Bull. Bot. Surv. India, 3: 393 – 394. Levan, A., Fredga, K. and Sandberg, A.A., 1964. Nomenclature for centromeric position of chromosomes. Hereditas, 52: 201 – 220. Lewis, W.H., Suda, Y., and Oliver, R.L., 1967. In chromosome number of Phanerogams 2. Ann. Mo. Bot. Gdn. 54: 178-181. Lewis, W.H., Taddesse, E., 1964. Chromosome numbers in Ethiopian Commelinaceae. Kirkia, 4: 213 – 5. Malla, S. B., Bhattarai, S, Gorkhali, M, Saiju, H and Kayastha, N. 1978a. In IOPB chromosome number reports LXII. Taxon, 27: 519–535. Marimuthu, K.M., Subramaniam, M.K., 1960. Haematoxylin squash method for root tips of Dolichos lablab L. Curr. Sci., 29:71 – 92. Morton, J.K., 1967. The Commelinaceae of West Africa: A biosystematic Survey. Jour. Linn. Soc. London, Bot., 60: 167 – 221. Palomino H., Benítez, B. V., Almeraya, P. M. and Ruaro, P. M. 1990. Estudios cromosómicos en seis especies Mexicanas de Comelináceas. Bol. Soc. Bot. México 50: 77–87. Patwary, M., Mirza, S. H. and Zaman, M. A. 1987. Meiotic behaviour of chromosomes and the nature of ploidy in four species of Commelina (Commelinaceae) from Bangladesh. Cytologia, 52: 175–181. Pitrez. 2001. Números cromossômicos de espécies de Commelinaceae R. Br. ocorrentes no nordeste do Brasil. Bol. Bot. Univ. São Paulo 19: 7–14. Raghavan, R.S., and Rao, S.R. 1961. Cytological observations on the Indian species of Commelinaceae. Curr. Sci., 30, 8: 310 – 311. Rao, R.S., Panigrahi, G and Kammathy, R.V., 1960. Cytotoxonomic studies on Indian Commelinaceae. Proc. Ind. Sci. Congr. 366 (Abst.). Rao, R.S., Sundra Raghavan, R., and Kammathy, R.V., 1970. Biosystematic studies in Indian Commelinaceae: The chromosome pattern and evolutionary trends. Bull. Bot. Surv., India, 12: 242. Renugadevi, K. and R. Sampathkumar. 1986. On the karyomorphological delineations in some taxa of Commelinaceae. J. Cytol. Genet. 21: 115–132. Renugadevi, K. and Sampathkumar, R. 1983. In IOPB chromosome number reports LXXIX. Taxon, 32: 320– 321. Shetty, B.V., and Subramanyam, K., 1961. Cytology of some taxa of Commelinaceae. Proc. 48th Indian Sci. Congr. (Roorkee), pp. 3: 299. Simmonds M.W., 1954. Chromosome behaviour in some tropical plants. Heredity, 8: 139 – 46. Umoh, E. O., Hossain, G. M. and Ene-Obong, E. E. 1991. On interchange complexes in Commelina diffusa Burm. f. from south eastern Nigeria. Cytologia, 56: 173–179. Umoh, E.O. 1993. Evidence of cytological and morphological evolution in Commelina L. Mem. Soc. Brot. 29: 105–118. Zheng, J. Y., Gu, C.Y. and Chen. R.Y.1989. Cytotaxonomical studies on Commelinaceae in China I. Chromosome numbers and karyotypes of some Chinese species. Pp.

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