Pleione 8(2): 416 - 426. 2014. ISSN: 0973-9467 © East Himalayan Society for Spermatophyte

Seedling characters for correlation of some species of Cohort Unisexuales (sensu Bentham and Hooker) in the Forest Patches of Dakshindinajpur, West Bengal

P. Kamilya and Ayan Das Department of Botany, Balurghat College, Balurghat 733101, Dakshindinajpur, West Bengal, India E-mail: [email protected] & [email protected] [Received 31.10.2014; Revised 19.12.2014; Accepted 24.12.2014; Published 31.12.2014]

Abstract Seedling morphology of twenty-four taxa of the families (= natural orders) and Urticaceae of the order (= cohort) Unisexuales (sensu Bentham & Hooker 1862 – 1883) have been studied from different forest patches of Dakshindinajpur District of West Bengal. These seedlings are described on the basic parameters for characterization of seedlings. Correlation of the taxa has been shown using seedling characters with UPGMA method to understand whether this correlation has any connection with natural system of classification. Key words: Seedlings, Seedling characters, Correlation, Dendrogram

INTRODUCTION Seedling development is an early juvenile stage in ’s life cycle. Non-volatile morphological characters of seedlings are very important to understand this initial process of plant life cycle (Paria et al 2006). Different taxa within the same or different groups exhibit diversity in this stage and on the basis of which correlation can be drawn to understand the variability in the natural characters among them. Many workers like Naidu & Shah 1978; Sampathkumar 1982; Balasubhramanyam & Swarupanandan 1986; Deb & Paria 1986; Kamilya & Paria 1993a,b, 1997; Paria & Kamilya 1999; Paria et al. 1990, 2006; Kamilya 2011; Duke 1965, 1969; De Vogel 1980; Bokdam 1977; Ng 1975; Popma & Bongers 1988; Guillermo et al. 2001 and Zanne et al. 2005 have worked to understand the impact of seedling characters on taxonomy. However, correlation among taxa on the basis of seedling morphology is rare in their works. In this work, an attempt has been made to understand the numerical relationship among taxa depending on seedling characters of twenty–four species of which sixteen of the family Euphorbiaceae and eight of the family Urticaceae under the order Unisexuales (sensu Bentham & Hooker 1862–1883). Numerical analysis has been carried out on the basis of their seedling characters to draw correlation among them. In addition, we tried to find out whether this correlation matches traditional system or not.

MATERIALS AND METHODS The study was conducted in different natural and seminatural forest patches of Dakshindinajpur district of West Bengal during August, 2013 to September, 2014. The total forest area in the district is 2.95 sq km (Mitra & Mukherjee 2013) with mean annual rainfall 1847.8 mm and mean annual temperature varying from 23 – 29º C. The vegetation is mostly semi-deciduous type (Kamilya 2011). P. Kamilya & Ayan Das 417 Seeds and seedlings are collected from their natural habitat in different forests at different times. The seeds are sown in garden of the Department of Botany, Balurghat College and seedlings were raised. The natural seedlings are then compared with the raised ones for identification. Herbarium sheets are made with the pressed and dried seedlings and diagnosed following Duke 1965; Burger 1972; DeVogel 1980 and Paria et al. 2006. Seedlings are then characterized and an artificial key to the taxa has been made for the identification of seedlings in natural habitat. For statistical analysis, characters were considered in numerical form as shown in Table–I. To understand the interrelationships among the taxa, a dendrogram has been created using DendroUPGMA software. DendroUPGMA makes clustering from a set of variables from similarity or dissimilarity matrix using Unweighted Pair Group method with Arithmetic Mean (UPGMA) algorithm (Garcia-Vallve 1999). The numerical characters are put in fasta– like format and the system is run in Pearson coefficient to measure linear correlation between the OTUs (Sneath & Sokal 1973). The outcome is in phylip format where mean branch divergence value between the taxa is displayed from which finally produce the dendrogram. The seedlings are displayed in the form of field photographs with highlighted paracotyledons and first two leaves for some of the studied species [PLATE - I] and hand drawings for others [PLATE - II]. Their characters are shown in the form of numericals (Table I) with the related characters for each value below the table. The taxa are arranged alphabetically in the table along with references to figure and voucher numbers. Though seedlings are described upto 7th to 10th leaves stage, but due to more prominent distinctive nature it was considered up to 1st two leaved stage only.

RESULT The observations on the structure of seedlings and the result of the numerical survey has been presented in Table 1. PLATES I & II presented the photographs and drawings of the seedlings under study. Based on the morphological characters a Key has been prepared to identify these seedlings in natural conditions: Artificial Key to the seedling species (Key valid for taxa studied only): 1. Seedlings phanerocotylar …………… …………… ...... …… 2 1a. Seedlings cryptocotylar …………… …………… ...... …… 22 2. Apex of paracotyledons other than retuse …………… …………...... 3 2a. Apex of paracotyledons retuse …………… …………… .....…… 19 3. Hypocotyl strictly rounded; first 2 leaves always opposite ………...... 4 3a. Hypocotyl may be rounded or angular; first 2 leaves opposite or alternate …....… 12 4. Apex of paracotyledons obtuse or shallowly sinuate, primary vein 1, 3 or 7; first 2 leaves, elliptic, widely elliptic or obovate, base cuneate or rounded, venation camptodromous ...... …. 5 4a. Apex of paracotyledons rounded or truncate, primary veins 5; first 2 leaves orbicular or ovate, base peltate, cordate or truncate, venation actinodromous …………… 9 5. Paracotyledons elliptic, oblong or flabellate; tip of first 2 leaves obtuse or mucronate .. 6 5a. Paracotyledons ovate; apex of first 2 leaves acute ………… Glochidion ellipticum 418 Table 1. Characters of seedlings of taxa under study in numerical form edig hrces f oe pce o oot Unisexuales Cohort of species some of characters Seedling P. Kamilya & Ayan Das 419 420 Seedling characters of some species of Cohort Unisexuales 6. Hypocotyl pubescent; number of primary veins in paracotyledons 3 or 7, venation actinodromous; first 2 leaves elliptic or widely elliptic, obtuse ….………...... 7 6a. Hypocotyl glabrous; number of primary veins in paracotyledons one, venation hyphodromous; first 2 leaves obovate, mucronate ………………… Breynia retusa 7. Paracotyledons oblong or flabellate, apex shallowly sinuate; first 2 leaves widely elliptic; first internode pubescent or tomentose …………… ...... 8 7a. Paracotyledons elliptic, obtuse; first 2 leaves elliptic; first internode glabrous ...... ………… Antidesma acidum 8. Paracotyledons oblong, slightly oblique, primary veins 5; base of first 2 leaves cuneate; first internode pubescent ………… ...... Bridelia stipularis 8a. Paracotyledons flabellate, not oblique, primary veins 7; base of first 2 leaves rounded; first internode tomentose …………… ...... Bridelia tomentosa 9. Hypocotyl glabrous; paracotyledons oblong, base rounded, apex rounded; base of first 2 leaves peltate or cordate, apex rounded or acute, glandular hair present on the petiole; heteroblastic development present …………...... 10 9a. Hypocotyl pubescent or sparsely pubescent; paracotyledons obovate, truncate, base cuneate; base of first 2 leaves truncate, apex acuminate, glandular hair not present; heteroblastic development absent …………...... 11 10. First 2 leaves orbicular, base peltate, apex rounded …….....… Jatropha podagrica 10a. First 2 leaves ovate, base cordate, apex acute ………… Jatropha gossypifolia 11. Hypocotyl sparsely pubescent; margin of first 2 leaves dentate; first internode round, tomentose …………...... Mallotus repandus 11a. Hypocotyl densely pubescent; margin of first 2 leaves serrate; first internode angular, hirsute …………...... Mallotus philippinensis 12. Apex of first 2 leaves acute, obtuse or acuminate, venation actinodromous or camptodromous …………... …………... …………...... ……… 13 12a. Apex of first 2 leaves always acute, venation always camptodromous …….…… 17 13. Petioles of paracotyledons adaxially deeply concave, paracotyledons suborbicular or flabellate, apex shallowly sinuate or rounded, venation actinodromous; base of first 2 leaves cuneate, attenuate, cordate or truncate, margin dentate or crenate dentate …………… 14 13a. Petioles of paracotyledons dorsiventrally flattened dorsally shallowly channeled, paracotyledons oblong, apex obtuse, venation hyphomous; base of first 2 leaves rounded, margin serrate ..…...... …………...... Trema orientalis 14. Apex of paracotyledons shallowly sinuate; first 2 leaves elliptic, venation camptodromous; first internode glabrous …………... ……...…… ...... 15 14a. Apex of paracotyledons rounded; first 2 leaves ovate, venation actinodromous; first internode pubescent …………… …………... …………...... 16 15. Paracotyledons flabellate; base of first 2 leaves cuneate, apex obtuse, margin dentate; first internode angular …………… …………...... Aporusa octandra 15a. Paracotyledons suborbicular; base of first 2 leaves attenuate, apex acute, margin crenate dentate; first internode round ………… …………. Suregada multiflora 16. Hypocotyl angular, pubescent; primary veins in paracotyledons three; first 2 leaves exstipulate, base cordate, apex acute; first internode angular...... denticulata P. Kamilya & Ayan Das 421 16a. Hypocotyl round, glabrous; primary veins in paracotyledons five; first 2 leaves stipulate, base truncate, apex acuminate; first internode round ...... Trewia nudiflora 17. Hypocotyl with pubescent or hirsute hair; paracotyledons ovate or obovate; base cordate or auriculate; base of first 2 leaves cuneate or rounded, margin serrate .… 18 17a. Hypocotyl with stellate hair; paracotyledons oblong; base rounded; base of first 2 leaves truncate, margin dentate …………… …………... Croton roxburghii 18. Hypocotyl pubescent; paracotyledons ovate, base cordate, apex obtuse; first 2 leaves alternate, elliptic, base cuneate; first ineternode round, pubescent .. Drypetes roxburghii 18a. Hypocotyl hirsute; paracotyledons obovate, base auriculate, apex rounded; first 2 leaves opposite, ovate, base rounded; first ineternode angular, hirsute ...... Tragia involucrata 19. Primary veins in paracotyledons one, venation camptodromous or hyphodromous; margin of first 2 leaves serrate or dentate ………...... ………...... 20 19a. Primary veins in paracotyledons two, venation actinodromous; margin of first 2 leaves entire ………...... …………... …………... Ficus benghalensis 20. Paracotyledons obovate, venation hyphodromous; first 2 leaves alternate elliptic, base cuneate, apex acute, margin serrate; first internode glabrous or hispid …………… 21 20a. Paracotyledons ovate, venation camptodromous; first 2 leaves opposite, base rounded, apex obtuse, margin dentate; first internode pubescent ….. Ficus religiosa 21. First 2 leaves and internode glabrous ……...... ………... Ficus racemosa 21a. First 2 leaves and internode tomentose ……...... ……….... Ficus hispida 22. Cataphylls present, base rounded, apex acute …………..... …………... 23 22a. Cataphylls absent, base attenuate, apex obtuse …………...... Streblus asper 23. Shape of first 2 leaves ovate, margin entire, surface of first internode pubescent ..... ………...... …………... …………...... Artocarpus heterophyllus 23a. Shape of first 2 leaves widely elliptic, margin serrate, surface of first internode hirsute …..……...... …………... …………...... Artocarpus lacucha

DISCUSSION In the prepared dendrogram (Figure 1), two principal clusterings are displayed– one with the twenty–one taxa showing phanerocotylar mode of germination and the rest three taxa with cryptocotylar mode of germination having mean branch divergence value or mbdv 40.934. The clustering of phanerocotylar genera is divided into two clades with mbdv 38.833 having seventeen species in one assemblage and four members in the other. The seventeen taxa are further segregated at mbdv 32.391 into two secondary clades with nine and eight taxa respectively. Each of these two secondary clades then forms two clusterings i.e, clusterings ‘a’ and ‘b’ for the first one and clusterings ‘c’ and ‘d’ for the second one.

Clustering ‘a’ consists of five taxa, where Glochidion ellipticum segregates from others at mbdv 18.829. Next, Breynia retusa and Antidesma acidum with Bridelia spp. are separated respectively at mbdv 14.719. The two species of Bridelia remain under same clade with mbdv 4.275 due to differences in their base of first two leaves and hair characters of first internode as mentioned in the artificial key. Four taxa of ‘b’ clustering show two groups at mbdv 23.039 containing one genus and two species in each. In one 422 Seedling characters of some species of Cohort Unisexuales

PLATE - I: 1. Antidesma acidum; 2. Aporusa octandra; 3. Bridelia tomentosa; 4. Artocarpus heterophyllus; 5. Artocarpus lacucha; 6. Drypetes roxburghii; 7. Ficus benghalensis; 8. Ficus racemosa; 9. Ficus hispida; 10. Ficus religiosa; 11. Jatropha podagrica; 12. Jatropha gossypifolia; 13. Mallotus philippinensis; 14. Mallotus repandus; 15. Streblus asper; 16. Suregada multiflora; 17. Tragia involucrata; 18. Trema orientalis; 19. Trewia nudiflora P. Kamilya & Ayan Das 423

PLATE - II: 1. Bridelia stipularis; 2. Breynia retusa; 3. Glochidion ellipticum; I4. Macaranga denticulata; 5. Croton roxburghii

Figure 1. Dendrogram showing clusters of 24 taxa 424 Seedling characters of some species of Cohort Unisexuales group, Jatropha gossypifolia and J. podagrica are placed at mbdv 13.871 with the differences of shape, base and apex of first two leaves as depicted in the artificial key. In the other group, Mallotus repandus and M. philippinensis are very much closer having the mbdv of 3.302. Clustering ‘c’ has five species, among which Trema orientalis forms a single clade from the rest by mbdv 23.482. The other four species are separated into two subclades with two members of each. The first subclad consists of Aporusa octandra and Suregada multiflora which are displayed at mbdv 3.535. Trewia nudiflora and Macaranga denticulata form the second subclade with mbdv 7.676. Clustering ‘d’ displays three taxa where Drypetes roxburghii and Tragia involucrata show closer proximity (mbdv 16.203) in one clade while Croton roxburghii makes another clade differing from the former at mbdv 23.648. The other primary clade with phanerocotylar taxa having mbdv 38.833 has four species of Ficus. Among these, F. racemosa and F. hispida remain in closer proximity with mbdv 5.170 as they are distinguished only on the hair characters of first internode. F. religiosa displays the next proximity with them with mbdv 26.039. F. benghalensis forms another distant clade within this group with mbdv 29.947 with references to the characters shown in the artificial key. The cryptocotylar clustering is made by three taxa, two species of the genus Artocarpus and one species of Streblus. S. asper forms a single clade at mbdv 18.613 apart from the rest two of this group. The two species of Artocarpus, viz., A. heterophyllus and A. lacucha depict mbdv 14.099 and represent a same clade only having only distinction of the characters like shape and margin of first two leaves as in the key.

CONCLUSION The order (Cohort) Unisexuales sensu Bentham and Hooker comprises of nine natural orders (= families), of which we have studied the seedling morphology of sixteen members of Euphorbiaceae and eight members of Urticaceae only. The recent classification systems have further splitted the above two families [e.g. Takhtajan 1997; Chase & Reveal 2009 (APG– III)]. Within this limited number of studied taxa, the phanerocotylar taxa, Ficus spp. of Urticaceae make separate clade being placed at mbdv 38.833 while Trema orientalis of the same family is placed within the clustering clade ‘c’ of Euphorbiaceae indicating its anomalous position. Besides cryptocotylar clade having taxa Artocarpus heterophyllus, A. lacucha and Streblus asper remaining seventeen taxa within the clusterings ‘a’, ‘b’, ‘c’ and ‘d’ displayed a single clustering after being separated from Ficus spp. Different subclades or secondary clades within the ‘a’, ‘b’, ‘c’ and ‘d’ are not parallel with the recent classification system of Euphorbiaceae. Therefore, seedling characters are strengthening the separation of these taxa within Euphorbiaceae and Urticaceae under Unisexuales. However, strict adherence is possible if large number of species are studied in such field. Some parallel behaviour of seedling subclades to other botanical disciplines has also been made. From view point of palynological evidence, Glochidion ellipticum and Breynia retusa show similarity in pollen characters (Pax & Hoffmann 1922), which is almost similar to seedling characters being placed in clustering ‘a’ of dendrogram. Similarly Glochidion ellipticum and Aporusa octandra are anatomically far apart from each other (Metcalfe & Chalk 1950) supporting the subclade of seedling. Thus, correlation of seedling data can partially fulfil natural clustering as well as modern taxonomy. P. Kamilya & Ayan Das 425 Acknowledgement The authors are grateful to UGC for providing financial help in the form of Major Research Project [F. No. 41-484/2012(SR) dt. 16.07.2012].

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