Schoenoplectiella erecta ( Poir . ) Lye ssp . raynalii ( Schuyler ) Beentje ( Cyperaceae ) – a new record to India from Ossudu Bird Sanctuary , Villupuram District , Tamil Nadu

Schoenoplectiella erecta subsp. raynalii (Cyperaceae) is recorded for the first time from India and Asia. This taxon was collected in Ossudu Bird Sanctuary, Villupuram district of Tamil Nadu, southern India. Detailed description including microscopic study of the glume and nutlets with digital images, morphological characters, habitat, and key characters between the two subspecies are provided.

ISSN 0974-7907 (Online); ISSN 0974-7893 (Print) During recurrent botanical surveys for the last three year (from September 2018 to August 2021) an interesting plant belonging to the genus Schoenoplectiella was collected from the shores of the freshwater Lake Ossudu, in Ossudu Bird Sanctuary, a protected area, in Tamil  Mao & Dash 2020; Narasimhan & Sheeba 2021) we come to know that this taxon was not yet recorded in Asia, India, and regional floras; however, Schoenoplectiella erecta ssp. erecta was recorded from northern India. In the Lake Ossudu Bird Sanctuary, three Schoenoplectiella species also occur: S. atriculata (L.) Lye, S. lateriflora (J.F.Gmel.) Lye, and S. juncoides (Roxb.) Lye.

Materials and Methods
Botanical exploration and ecological studies were conducted from September 2018 to August 2021 in Ossudu (Figure 1) along the Coromandel Coast, Villupuram district of Tamil Nadu. Ossudu Bird Sanctuary falls in two political boundaries, viz., Union Territory of Pondicherry and Villupuram district of Tamil Nadu. During the survey an unfamiliar sedge was found and collected from the eastern shores of Ossudu Lake and the collected specimen was processed and deposited at Herbarium, French Institute of Pondicherry (HIFP) for further studies. Camera attached light microscope was used to examine the morphological features of glume and nutlets to understand the morphological differences.

Results
The inflorescence of Schoenoplectiella is capitate or anthellate. The anthella of spikelets are simple to decompound due to the presence of branched or unbranched peduncles with few to numerous sessile spikelets and they are densely crowded. This characteristic feature was recorded in both the inflorescence of S. lateriflora and S. erecta. On critical examination of the herbarium specimens deposited at AURO (4751, 10317, 11940), S. lateriflora was 10-20 cm high with decompound inflorescence, peduncles 3-15 mm high, style 3-branched, achene trigonous whereas S. erecta is more than 30 cm high, inflorescence decompound, peduncles 15-65 mm long, secondary peduncles to 8-12 mm long, style 2-branched and nutlet plano-convex.
The two known subspecies, Schoenoplectiella erecta ssp. raynalii is similar to S. erecta ssp. erecta but differs by its style and nutlets. Following key can be used to differentiate them:

Conservation status
Considered as 'Least Concern' on the IUCN Red List of Threatened Species (Mesterházy 2020), and in recent days the range of distribution has been extended from Africa, America to Asia, and Australia. Probably the migratory granivorous ducks (Mallards/the whistling ducks) might have played a major role in extending the distribution of this species. This study also proves the report of Kleyheeg et al. (2019) that the granivorous water birds disperse viable seeds of wetland plants over long distance during their migration. The censuses of large flocks of such migratory granivorous wintering or breeding ducks were recorded during this study and previous ones (Perennou 1990;Davidar 2011;Mathevet et al. 2020).
Notes: As per the revision of Hayasaka (2012) and Xanthos & Browning (2015) the subspecies 'raynalii' could be easily distinguished by having 3-fid stigmas, planoconvex nature of nutlet with distinct rugose surface, while its typical subspecies 'erecta', has 2-fid stigma, biconvex nutlet with moderate wrinkled surface. The surface of S. lateriflora nutlet is otherwise same that of S. erecta ssp. raynalii but the former species has trigonous nutlet with 2-fid stigmas.
In Schoenoplectiella, interspecific natural hybridization exhibits range of variations in plant height, culm width below the inflorescence, shape and length of overtopping inflorescence, glume dimensions at apex, anther crest length, style branch and length, achene dimensions and surface sculpturing were very well studied (Browning 1992;Hayasaka 2012). Meanwhile the variation in the shape of inflorescence was overlooked by previous taxonomic accounts (Ohwi 1944;Koyama 1958). Though, in India we observed that the length of primary and secondary peduncles of the inflorescence is much longer than the (iso)type specimen from KEW image and specimen from the University of South Florida Herbarium (20709).