Indian Journal of Biological Sciences, 21 : 51-58, 2015

MORPHO - ANATOMICAL STUDIES OF CYPSELAS IN THE TRIBE () Radharaman Bar and Sobhan Kr. Mukherjee* Department of Botany, Bangabasi Morning College, Kolkata -700 009, India *Department of Botany, University of Kalyani, Kalyani -741 235, India

ABSTRACT  Senecioneae is one of the unique tribes recognized by Cassini among the 43 tribes of Asteraceae. Present study is based on the morpho-anatomical characters of cypsela among one species each ofBarkleyanthus [Barkleyanthussalicifolius (Kunth) H. Robinson & Brettell], Packera [Packeradimorphophylla (Greene) W. A. Weber & Á. Löve] and (Senecioelegans L.)under the tribe Senecioneae. Morphological characters like apical part of the cypsela, surface hairs, structure of carpopodium, pappus bristles type and anatomical features such as pericarpic tissue arrangement, testal layers and endosperm are taxonomically significant. The studied characters has important role in isolation of taxa at species level. An artificial key is provided on the basis of macromorpho-anatomical features of cypselas for identification of the studied species. The objective of the present study is to analyse the detailed morpho-anatomical structures of the cypselas and also to show the relationships among them.

Key words: Asteraceae, Carpology, Senecioneae

INTRODUCTION recognized by Cassini (1819), Lessing (1832) Morpho-anatomical characters play an and de Candolle (1836-1838), Bentham important role in isolation of taxa at species (1873), Robinson and Brettell, (1973), Turner level. One seeded, indehiscent, unilocular fruit and Powell (1977), Nordenstam (1977), Jeffrey of the belonging to the family and Chen (1984), Bremer (1994), and Pelseret. Asteraceae is commonly known as cypsela (or al. (2007). Recently, molecular phylogenies achene). Micro-morphological and anatomical redefined the tribe Senecioneae more characters of these fruits have been critically narrowly and it includes approximately 1000 examined by many workers to assign the species (Pelseret. al., l.c.) and 150 genera plants in the family Asteraceae into different (Nordenstam, 2007). tribes moreprecisely. Present study analyses morphological and The unique Tribe Senecioneae (Asteraceae) anatomical characters of cypselas of three with “bifurcate styles with separate stigmatic species under this tribe and tries to find the areas, apically truncate sweeping hairs” was relationships among them.

* Corresponding author : e-mail: [email protected]; [email protected]

51 52 Bar and Mukherjee

MATERIALS AND METHODS heteromorphic cypselas, all the above The investigated cypselas (Table 1) were mentioned characters were studied for both supplied by the 2nd author of the paper in the ray and disc cypselas. Observations were the form of herbarium specimens from Havard carefully noted. For both morphological and University Herbaria. The present study anatomical studies, cypselas were softened includes 3 species belonging to genus (Mukherjee and Sarkar, 1994), carefully Barkleyanthus, Packera and Senecio under the dissected, stained (Johansen, 1940) and Tribe Senecioneae of the family Asteraceae. outline diagrams were drawn by prism type Table 1: Sources of the material Sl. Name of the Name of the studied taxa Locality Collection No. No. tribe

1 Senecioneae Barkleyanthussalicifolius (Kunth) Havard University Herbaria, 150 H. Robinson & Brettell Cambridge, USA 2 " Packeradimorphophylla (Greene) ,, 11372 W. A. Weber & Á. Löve 3 " SenecioelegansL. ,, 63058

Fully matured and intact cypselas were Camera Lucida. Suitable images were taken collected for investigating stable and perfect using camera equipped microscope. stage of each character. Mature, preserved, dry 10 cypselas were randomly taken for each of DISCUSSION the three species and observed for Cypselar Morphology morphological (Table 2) and anatomical (Table Present study includes cypselas of 1 species 3) study under the Olympus Stereo dissecting each of Packera, Barkleyanthusand Senecio. The microscope (DM) and Metzer binocular length of the cypselas of different species is compound light microscope (LM). not a reliable distinguishing character because Morphological characters like types, the length of one species overlaps with others. orientation, distribution, nature of hair, gland, Cypselas are usually narrow oblong or carpopodial cells, surface cells, other oblanceolate (Barkleyanthussalicifolius)or epidermal structures and anatomical features seldom elliptic (Senecioelegans). Cypselas are such as pericarpic tissue arrangement, testal often terete (Senecio) to sub-terete or layers, and endosperm were critically sometimes compressed (Barkleyanthus). examined. Number, colour, arrangement, Number and shape of the ribs are significant length of pappus were also observed. for characterization of taxa. Length and width of the cypselas were Hairs are distributed in 1-4 rows on each measured by graph paper, scale and in few furrow or randomly throughout the surface cases by ocular and stage micrometer. In the or at the furrows, except in present study the length of cypselas means Packeradimorphophylla, where it is absent, the length of the body of cypselas from apical while mucilage hairs is absent in all the end excluding pappus up to the basal studied species. Nordenstam (1977) reported meristematic zone (carpopodium). The widest mucilaginous hairs in the members of part of the cypselar body was measured as Senecioneaeand named the hairs as “twin or the width of the cypselas. In case of duplex hairs”. While present LM observations

Indian Journal of Biological Sciences, Vol. # 21, 2015 ISSN 0972-8503 Morpho-Anatomical Studies of Cypselas in the Tribe Senecioneae... 53 clearly show that tips of the twin hairs are Stylopodium has significant role for obtuse or rounded but not sharply pointed. characterization of the studied taxa. Similar observations were reported by other Stylopodium is knob on short column in two workers (Mukherjee, 2001b; Mitra and species (Barkleyanthus and Senecio). While, Mukherjee, 2003). previous reports of short angular tube Table 2: Comparative morphological features of the studied cypselas.

Name of taxa Shape Surface Pappus Carpopodium Barkleyanthussalicifolius Narrow Rough with Represented by 24 – 26, Symmetric, oblong or tomentose hairs equal, free, circular ring oblanceolate homomorphic, like unbranched, barbed bristles; occur in 2-3 rows Packeradimorphophylla Oblong Glabrous Represented by 23 – 25, Ill developed equal, barbed bristles; occur in 2-3 rows Senecioelegans Elliptic Ribbed; papillose Represented by 28 – 30, Symmetric, hairs at ribs, rough equal, barbed bristles; circular ring at furrow occur in 3 rows like

Table 3: Comparative anatomical features of the studied cypselas.

Name of taxa Barkleyanthussalicifolius Packeradimorphophylla Senecioelegans

Cypselar shape in Deformed spindle shaped Ribbed spindle shaped in Ribbed oval in cross T.S. in cross section cross section section Mesocarpic Present Present Very small amount parenchyma

Mesocarpic Absent Absent Thick walled, sclerotic cells compactly arranged, hexagonal, with large round lumen Cell content of Disorganized, partially Partially cellular, irregularly Partially cellular, testa cellular oriented compactly arranged, Testal cell shape Layer of crusted Thick walled, parenchymatous Thick walled, parenchymatous cells cells parenchymatous cells Endosperm Thick walled, square, Thick walled, irregular Thick walled, parenchymatous shaped, parenchymatous, compressed, compactly arranged compact parenchymatous cells rectangular shaped, Endosperm layer 2 – 3- seriate 3 – 4- seriate Uniseriate No. of secretory Secretory ducts 3 in each Secretory ducts 3 in each Secretory ducts 4 in duct cotyledon cotyledon. each cotyledon

Indian Journal of Biological Sciences, Vol. # 21, 2015 ISSN 0972-8503 54 Bar and Mukherjee likestylopodium (Mitra and Mukherjee, l.c.) or reported by others (Mitra and Mukherjee, l.c.). stylopodium free from the nectary or the style Pappus is often represented by numerous base is situated at the top of the persistent, barbellate bristles usually occur in nectary(Category-IV - Mukherjee, 2005) also 2-3 rows (Barkleyanthus and Packera), 3-seriate found. (Mitra and Mukherjee, l.c.) or absent Carpopodium may be symmetric or (Nordenstamet al., 2009; Jana and Mukherjee, asymmetric and thick-walled cells are 2013). These features of pappus could be arranged in 1-row (Barkleyanthusand Packera) employed for identification of taxa. or4- angled complete ring in 2 rows as

Indian Journal of Biological Sciences, Vol. # 21, 2015 ISSN 0972-8503 Morpho-Anatomical Studies of Cypselas in the Tribe Senecioneae... 55

Indian Journal of Biological Sciences, Vol. # 21, 2015 ISSN 0972-8503 56 Bar and Mukherjee

Cypselar Anatomy Senecioelegans(10). Truly cypselar wall consists of pericarp, 2) Mesocarpic zone with phytomelanin layer. testa and endosperm. The mature pericarp Sclerenchymatic braces absent, shows a marked variation in the structure parenchymatous zone forms continuous of mesocarpic zone. The number, size and cylinder - Packeradimorphophylla(11), shape of ribs are more or less diacritical Barkleyanthussalicifolius(9). Mitra and feature of cypselas of the studied species. Mukherjee (l.c.) also have the similar Number of sclerenchymatic braces is usually observation like the present study. identical with the number of ribs as In the studied genera, the number of vascular shown in parenthesis after each species traces ranges from 9 - 11 and pericarp devoid mentioned below. of secretory cavity except Senecioelegans. On the basis of distribution of different types Sometimes vascular traces wereobserved in of tissues within the mesocarpic zone, between the sclerenchymatous braces cypselas could be distinguished into following (Mukherjee, 2001). The pericarp of types: Packeradimorphophylla a n d 1) Mesocarpic zone without phytomelanin Barkleyanthussalicifolius,are nearly similar, layer. Sclerenchymatic braces unilobed, 10, indicating their systematic affinity. separated by parenchymatous zone which is General structure of the testa is more or less narrower than each sclerenchymatic brace - uniform in studied species of Senecioneae. The

Indian Journal of Biological Sciences, Vol. # 21, 2015 ISSN 0972-8503 Morpho-Anatomical Studies of Cypselas in the Tribe Senecioneae... 57 presence of crystals in the ovary wall or achene Director of the Harvard University Herbaria, wall have taxonomic importance (Drury and 22 Divinity Avenue, Cambridge, MA 02138, Watson, 1965; Mukherjee, 2001). Such U.S.A.( (A, GH) and Dr. Anthony R. Brach, crystals are not found in the studied Curatorial Assistant and Research Associate, members. Harvard University Herbaria, for sending Endosperm is often uniseriate (Senecioelegans) mature identified cypselae for our studies. or 2-, 3- seriate (Barkleyanthussalicifolius) or 3, 4- seriated (Packeradimorphophylla) in mature REFERENCES cypselas. Bentham, G. (1873): Notes on the classification, history, In general, internal structure of the cypselas and geographical distribution of Compositae. in the studied members of Senecioneaeare Journal of the Linnean Society, Botany 13: 335 – more or less identical with the members of 577. the tribe Anthemideae (Kynclova 1970; Bremer, K. (1994): Asteraceae. Cladistics and Classification. Timber Press, Portland. Mukherjee and Sarkar 1991)indicating their Cassini, H. (1819): Suite de Sixieme memoire sur la systematic affinity. Therefore, cypselar family des Synantherees, contenant les features are equally important for the isolation characteres des tribus. Journal de Physique, de of taxa at the generic and species level along Cassini, d’ Histoire Naturelleet des Arts 88: 189-204. with other floral features as advocated by De Candolle, A.P. (1836): Compositae. Part I. In many taxonomists. “Prodromus Systematics NaturalisRegniVegetabilis” Vol.5, Paris. AN ARTIFICIAL KEY TO THE STUDIED SPECIES De Candolle, A.P. (1838): Prodrommus Systematics OF THE TRIBES OF SENECIONEAE NaturalisRegniVegetabilis, Vol. 6. Treuttel&Würtz, 1a. Anticlinal walls of surface cells are straight Paris. Drury, D. G. and Watson, L. (1965): Anatomy and the in SEM analysis; epicarpic cells oval; taxonomic significance of gross vegetative mesocarpic sclerotic braces present; testa morphology in Senecio. New Phytol. 64: 307 – 314. attached with pericarp; endosperm uniseriate Jana, B.K. and Mukherjee, S.K. (2013d): Distributional ...... Senecioelegans analysis of epappose genera of Asteraceae of the 1b. Anticlinal walls of surface cells are not world with special reference to India. straight in SEM analysis; epicarpic cells Phytotaxonomy. 13: 23-39. rectangular or square; mesocarpic sclerotic Jeffrey, C. and Chan, Y. L (1984): Taxonomic studies braces absent; testa separated from pericarp; on the tribeSenecioneae (Compositae) of Eastern endosperm multiseriate ……… …(2) Asia. Kew Bull. 39(2): 205 – 446. 2a. Ribs prominent; cypselar surface Johansen, D.A. (1940): Plant Microtechnique. Mc. Graw Hill. New York. pubescent; carpopodium cells Kynclova, M. (1970): Comparative morphology of morphologically and anatomically achenes of the tribe Anthemideae Cass. differentiated; ribs not more than 10 (Asteraceae) and its taxonomic significance...... Barkleyanthussalicifolius Preslia. 42: 33-53. 2b. Ribs inconspicuous; cypselar surface Lessing, C.F. (1832): Synopsis GenerumCompositarum. glabrous; carpopodium cells morphologically Duncker&Humbolt, Berlin. and anatomically not well differentiated; ribs Mitra, S. and Mukherjee. S.K. (2003): Morpho- more than 10 ...... Packeradimorphophylla anatomical study of cypsela of Acknowledgements Crassocephalumcrepidioides (Benth.) S. Moore – A Authors are grateful and thankful to the rare plant of West Bengal (India). J. Swamy Bot. Cl. 20:19-22.

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Indian Journal of Biological Sciences, Vol. # 21, 2015 ISSN 0972-8503