The present investigation is on the chromosome count of Pyrrosia porosa (C. Presl) Hovenkamp, a fern of Kolli Hills, Eastern Ghats, South India. The young sori were collected from Kuzhivalavu of Kolli Hills. The sori showed 37 bivalents at first meiosis of spore mother cells. Diploid cytotype of P. porosa has been reported from Eastern India and Eastern Himalaya so far. This is the first report of the diploid cytotype from South India.

Vijayakanth P, Sahaya SS (2017) Pyrrosia porosa (C. Presl) Hovenkamp – A New Diploid Cytotype of South India from Kolli Hills of Eastern Ghats, Tamil Nadu, India. Int J Plant Biol Res 5(1): 1057.

•    Pyrrosia porosa
•    Diploid cytotype; first report of South India
•    Kolli Hills
•    Eastern ghats

The Kolli Hills is a part of the Eastern Ghats, which is a mountain range that runs almost parallel to the east coast of Tamil Nadu. Kolli Hills are located in Namakkal district of Tamil Nadu. It extends to an area of about 418 km2 between 11° 10’ - 11° 30’N latitude and 78° 15’-78° 30’ E longitude (Figure1). Its elevation ranges from 700-1400m. Pyrrosia porosa (C. Presl) Hovenkamp is a tropical and subtropical species, and is commonly distributed in South India. This plant is in the form of lithophytes and epiphytes found mostly along the road sides and rarely found inside the forest. The species was found in Western Ghats [1,2] and Kerala, South India [3,4]. Tetraploid cytotype of this taxon was reported from Himachal Pradesh of Western Himalaya and Nilgiris of South India [5-7]. Diploid cytotypes were recorded from Parasnath hills in Eastern India and Darjeeling in Eastern Himalaya [8,9]. The present investigation deals with the chromosome count of this taxon from Kolli Hills, South India.

The developing sori were collected in the early morning (6.00 to 7.15am) and fixed in Carnoy’s fluid. For meiotic chromosome studies, the acetocarmine squash technique was followed [10]. The chromosomes were seen from spore mother cell before diplotene and diakinesis of the first division of meiosis. The best preparation was selected for photographs using the Olympus - CX21 microscope under 100 X magnification. The herbarium specimens were deposited in the Centre for Cryptogamic Studies, Department of Botany, St. Joseph’s College (Autonomous), Tiruchirappalli, Tamil Nadu, India.

Plant description

Pyrrosia porosa (Presl) Hovenkamp, Blumea 30(1): 208. 1984.

Synonym: Niphobolus porosus C. Presl, Tent. Pterid. 202. 1836.

Rhizome creeping, fully covered by scales, lanceolate in shape, 4 × 1.5 mm, brown colour, base cuneate or round, apex acuminate, margin fimbriate, frond simple, monomorphic, indistinctly, linear-oblong to lanceolate, up to 25.5 × 1.6 cm, narrow in apex and base, margin entire, vein distinct, primary veins ascending, parallel, secondary veins connecting primary vein, tertiary veins indistinct, frond dark green, lower surface of frond pale brown, stellate hairs (1mm) in two layer. Sori numerous, towards the distal half of the frond, orbicular, secure by stellate hairs, marked by dark spot above the frond (Figure 2).

Specimen examined

Kuzhivalavu, Kolli Hills. CCSH 311, 22.4.2015

Each spore mother cell of P. porosa shows 37 bivalents (Figure 3). This is sexual diploid in nature. 64 normal spores were observed in one sporangium. These results were confirmed with the report of Roy et al. [8], Also the same report from Eastern Himalaya [9]. The result obtained by this investigation is the first record of South India.

1. Manickam VS, Irudayaraj V. Pteridophyte flora of the Western GhatsSouth India. BI Publications India Pvt Ltd, New Delhi. 1991.

2. Benniamin A. Fern diversity of the Western Ghats if India. PhD Thesis, Manonmaniam Sundaranar University, Tirunelveli, Tamil Nadu. 2004.

3. Nampy S, Madhusoodanan PV. Fern flora of South India: Taxonomy revision of Polyploid of Ferns. Daya Publishing House, New Delhi. 1998.

4. Easa PS. Biodiversity documentation for Kerala-IV Pteridophytes. Kerala Forest Research Institute, Peechi, Kerala. 2003.

5. Manton I. ‘Problems of Cytology and Evolution in the Pteridophyta’. Cambridge University Press, Cambridge. 1950.

6. Roy RP, Sinha BMB, Pandey SN. Cytotaxonomic studies in some epiphytic ferns of Parasnath hills. Journal of Cytology & Genetics. 1969; 4: 97-104.

7. Bir SS, Trikha CK. Cytological evolution of Polypodioid ferns with particular reference to the Himalayan forms. In Nair PKK. (eds.) Glimpses in Plant Research IV, Vikas Publication Pvt. Ltd, New Delhi, India.1979; 98-130.

8. Khullar SP, Sharma SS, Verma SC. In: Bir SS. SOCGI plant chromosome number reports- VI. Journal of Cytology and Genetics. 1988; 23: 38-50.

9. Irudayaraj V, Bir SS, Manickam VS. Cytology of ferns from the Nilgiris, South India. Proceeding 80th Indian Science Congress, Part III Section 6 Botany, Abstract. 1993a; 76.

10. Irudayaraj V, Bir SS, Manickam VS. Cytology of ferns from the Nilgiris, South India. Fern Gazette 1993b; 14: 161-170.