Polytrias indica ( Poaceae : Andropogoneae ) : the name , species identity and its distribution in India

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Polytrias
Polytrias Hack. is a genus of the family Poaceae, described with single species P. praemorsa (Nees) Hack.It is a prostrate grass from Java, bearing shiny, reddishbrown hairy racemes with each rachis joint (node) bearing two sessile and one pedicellate spikelets, and the flowering glume ending with an awn (Hackel 1887(Hackel , 1896)).Based on morphological characters, Clayton & Renvoize (1986) included Polytrias Hack. in the subtribe Saccharinae along with genera such as Eriochrysis P. Beauv., Eulalia Kunth, Imperata Cirillo, Microstegium Nees and Pogonatherum P. Beauv. of Andropogoneae, an ecologically and economically important tribe of C 4 species, which include the important crops of the world such as maize, sorghum and sugarcane.The genus Polytrias shows closer affinity with Eulalia and Microstegium of the Saccharinae on one hand and Sorghastrum of Sorghinae on the other, as per the multilocus phylogeny and phylogenomics (Welker et al. 2016).
The Polytrias Hack.(1887) resembles the genus Pogonatherum P. Beauv.(1812) in its terminal solitary racemes and articulate axis, but differs in the ternate spikelets.It is allied to Eulalia Kunth (1829) from which it differs strikingly in its solitary racemes and the spikelets in triads but both differing from Ischaemum L. (1753) in their slender joints of the rachis, lower glumes not winged, never tuberculate or rugose.In certain herbaria (e.g., Taiwan), Polytrias was often misidentified as Eulalia leschenaultiana (Lin et al. 2013).In Flora of British India, Hooker (1896) treated this taxon as doubtful and listed it in the excluded species of Andropogon.Further, he (p.210) mentioned A. diversiflorus Steud. (in Zoll., Syst. Verz. 58. 1854) as Polytrias praemorsa Hack., a Javanese plant that was not hitherto found in British India.But, later, Veldkamp (1991) brought to light that one of the collections made by J.D.  Veldkamp (1991).
The genus Polytrias Hack.was first reported from India from the Indian Botanic Garden, Shibpur, West Bengal, by Jain & Pal (1968) as P. amaura (Büse) Kuntze.This grass was widely known as Polytrias amaura, based on Andropogon amaurus, which is a superfluous name for A. diversiflorus, as mentioned above.Polytrias amaura was first noticed as a weed in Sector 1 of the Botanic Garden but later it was found to spread all over by the year 1985 (Pal 1987).Karthikeyan et al. (1989) have placed this record/taxon under Eulalia amaura (Büse) Ohwi for the checklist of monocots of India.
Conversely, Polytrias indica was reported from India as a garden escape, or on the path of naturalization.It is of interest to note that the specific epithet "indica" has nothing do with the country India, as of nativity.It could be due to the historical reason.In Linnaean time, several European botanists treated the Southeast Asian region under a common name, India (or East India, Indiae Orientale, Indiae Orientalis).Moreover, on herbarium sheet, on the top-left side he inscribed the origin of the plant as Planta Ind. Orient., which could refer to either Java or Ceylon (Wijnands et al. 2017).Perhaps, it could be the reason why Houttuyn (1792) did not bother to pay attention to the precise locality when he named 'Phleum indicum'.
One can also know this fact from the Merrill's (1938: 320) own making.Realizing Houttuyn's name, Merrill made the observation that Houttuyn's material was from Java and his species was clearly indicated as new (he used 'mihi' for the binomials coined by himself -cf.Wijnands et al. 2017: 158), following the short Latin diagnosis.To Merrill, Houttuyn's illustration is a reasonably good one for the grass currently known as Ischaemum ciliare Retz., which is common in Java, and more definitely Houttuyn's species seems to be the same as Ischaemum ciliare Retz.var.genuinum Hack.In fact, Merrill mentioned I. ciliare Retz.as a synonym under the combination.Above all, Veldkamp (1991: 180) actuality pleaded for the reinstatement I. ciliare Retz.for the Ischaemum indicum auct.non Merr.though it was not taken into the cognizance by the subsequent workers on Indian grasses.When the 'www.theplantlist.org'mentions the name Ischaemum indicum (Houtt.)Merr.as a synonym of Polytrias indica (Houtt.)Veldkamp, many grass workers perhaps simply adopted that name.Efloraofindia (Google sites) is no exception in this regard.
Distribution: (a) Global: Native to SE Asia, including China (Chen & Phillips 2006).It is found in tropical Australia, south-eastern China, Malaysia, Myanmar, New Guinea, the Philippines and Vietnam (Lin et al. 2013).The limited (three) specimens at Kew are from Borneo, Java and Thailand.It is an introduction elsewhere as a lawn grass.It is reported from grassy places on mountain slopes, grassy spaces, lawns, wastelands and roadsides.(b) India: It is known from Meghalaya (Veldkamp 1991) and West Bengal (Jain & Pal 1968) and not yet reported form Andhra Pradesh and Telangana (V.S. Raju, pers.obs.), Kerala (P.V. Sreekumar, pers.comm.),Tamil Nadu (Kabeer & Nair 2009), Maharashtra (P. Lakshminarasimhan, pers. comm.) or other parts of India.(c) Andaman Group of Islands: Pal (1987) reported its presence in Andaman Islands of a collection made in Nov. 1976 (Gupta 4096, CAL) which is yet to be traced; however, there are eight collections at PBL from Andaman & Nicobar Islands in the folders of Polytrias indica which were originally labelled by the collectors as Ischaemum indicum.We identify all these as of Ischaemum ciliare Retz.
Note: It is a good lawn and pasture grass of great value (Bor 1960;Baker & Brink 1968) and as well pollen donor to bees (Baker & Brink 1968;Pal 1981).It is a short-day plant and flowers in winter (Remo-castro & Tabbada 1977).Its pollen may cause allergy to humans (Dacanay & Artiaga 1969) when grown as a lawn grass.Therefore, it is to be classified as an environmental weed (present study).
Invasive Weed Status: Polytrias indica is reported to be invasive outside its native range as per PIER (http:// www.hear.org/pier/species/polytrias_indica.htm) and HEAR (gcw/species/polytrias_amaura/).It was reported decades back as an escape in India (Jain & Pal 1968;Pal 1987).However, it is yet to be confirmed as an invasive species on the Indian mainland or the Andaman group of islands.
IUCN Red List Status: Kumar (2013) assessed Polytrias indica as Least Concern (LC).The assessment they made is of Ischaemum indicum sensu Merr.and it shall belong to Ischaemum ciliare Retz.It is a clear case of misapplication of name of the lawn grass Polytrias indica to yet another but marsh grass from Java which entered into India earlier to 1791.The IUCN assessment of Polytrias indica, as of now, needs correction.

Conclusion
Polytrias indica (Houtt.)Veldkamp is the name of Java Lawn Grass misapplied to another grass from Java found very common in India or elsewhere which is to be rightly called Ischaemum ciliare Retz.Although Veldkamp (1991) clearly brought out the distinction of Polytrias indica of its ternate flowers, the confusion continues in Indian grass literature.It pertains to the subtribe Sacchrinae rather than Ischaeminae of Andropogoneae.The 2013 IUCN Red List assessment of Ischaemum indicum sensu Merr.(i.e., I. ciliare Retz.) was attributed to Polytrias indica as a result of misapplication of the name.Although Polytrias indica is stated to be invasive outside its native range, it is yet to be confirmed as such in India.Thus far, it is known from Meghalaya and West Bengal of India.