Identification of Indian Sida through mericarp

Background: some of the species of Sida are being used as medicine in traditional therapies and available in the market as broken plant parts. Therefore, adulteration is very common. A study was conducted to identify the Indian Sida L. through morphological features of mericarp found in the market samples. Methodology: the fruits of Sida are collected from field in flowering and fruiting stage. The identity of the species were determined and dried mature fruit (schizocarp) of specimens were dissected and studied under compound microscope. The market samples were purchased from various parts of the India and fruits were investigated to match the key characters have been found during the study. Results: mericarp of Sida possess huge diversity and it is a reliable character for identification. Each species of Sida has unique mericarp structure. However, some of the species like, Sida alba have four different types of mericarp but they different from mericarps of other species. I have come across with 27 different types of mericarps in Indian Sida. Conclusion: mericarp morphology is a key character to determine the identity of the species. Based on mericarp features a bracketed dichotomous key has been prepared for identification. The species of Indian Sida may be identified the help of mericarp morphology.


INTRODUCTION
Few species of Sida are used in different traditional systems medicines and sold in market.The demand is high and drugs are sold as broken plant parts, adulteration is very frequent in crude drug market. 1To avoid frequent adulteration the identification of Sida species through mericarp is very necessary.These adulterants are responsible to deteriorate the quality and efficacy of the drug.Moreover, they may cause deleterious effect on human health. 2The most commonly sold species is Sida cordifolia (seeds are being used as Ayurvedic drug named "Bala").][10][11][12] Sivarajan et al., in J. Taiwan Mus.45(1):65-73(1992), published mericarp morphology of Indian Sida in relation to plant taxonomy, 13 though it is a good study but not useful in crude drug identification because: (1) it is mainly based on fresh collections; (2) descriptions are not suitable for pharmacognosy; (3) identification key is not provided; (4) some of the species given are not recognized by Flora of India 14 and few species are merged and few species names falls under unresolved category; (5) after that some new species in genus Sida have been added.Paul and Nayar had studied seed coat of seven species of Sida through Scanning Electron Microscope (SEM) but it is different from pharmacognosy of the species. 15Further, SEM a is sophisticated technology not easily available.The pharmacognosy of either all the Indian Sida or pharmacognosy through fruit or mericarp morphology are hitherto unknown.][18] The Sida fruit is a schizocarp which splits away at maturity in to mericarp.The mericarp is the seed-containing part of a fruit that do not form a single unit.It has been observed that fruit (mericarps) of Sida species show significant variation from species to species.As per Waalker, mericarp char-acter is more reliable key character than highly plastic foliar and stipular characters. 19The fruits or mericarps or both may be selected by careful examination of the market drugs and the identity of the species may be establish with the help of compound microscope.The study was designed to test the hypothesis: each and every species of Sida are unique in mericarp morphology.Therefore, present study was focused on identification of market samples of Sida species through morphological studies to achieve following objectives: (a) authentication of the crude drugs sold in market as Bala (Sida cordifolia) and other species of Sida through morphological studies of mericarp; (b) development of identification key for India's Sida using morphological features of mericarps.

Methodology
The fruits of Sida are collected from field in flowering and fruiting stage.The identity of the species were confirmed through traditional taxonomic studies, and matched with authentic specimens submitted in Central National Herbarium (CAL) and Flora of India. 14he dried mature fruit (schizocarp) of specimens were dissected and studied under Nikon SMZ 1500 microscope and photographs were taken with the help of inbuilt camera.In crude drug market, Sida species is sold in dried form therefore the dried fruits are studied to observe the similar findings.Further, market samples were collected/purchased from various parts of the India (i.e.New Delhi, Haridwar, Reshikesh, Kolkata, Jaipur, Lucknow, Coimbatore, Hyderabad and Mumbai) and fruits were studied to match the key characters which have been found during the study.Sida repens, S. elongata var.balica and S. tiagii are not re-collected after their first report.Therefore, line drawings and descriptions are given on the basis of published literatures. 20,21Similarly, I was dependent on literatures for S. linifolia and S. subcordata. 19,22servations It has been observed that the mericarps morphology of Sida species are varies from species to species.The mericarps of all the 14 Sida species of India have been studied to recognize key characters which may help in authentication of the specimens.

Species of Sida are in India
Flora of India has given 12 species of Sida in India [14] .Sivarajan and Pradeep were proposed 17 species, however, the three species have been merged and few names are unresolved [22][23][24][25] Furthermore, there are some confusion in the identity of S. alba and S. spinosa, some literatures consider them as conspecific whereas some as heterospecific. 14In present study two criteria have been followed to recognized the species: (1) Flora of India (1993) and ( 2) morphology of mericarp.It means only two species are added effectively in genus Sida i.e. S. subcordata and S. linifolia (http://www.theplantlist.org/).Therefore, 14 species of Sida are considered.

Not all the species of Sida are common
The Sida repens and S. elongata var.balica have not been re-collected after their first collection in 1983 from Nilambur forest areas of Kerala.Both the specimens are housed at Calicut University Herbarium (CALI).S. tiagii Bhandari has the similar fate, it has been not recollected after first collections in 1962 from sandy ground of Barmer, Rajasthan.The specimen is stored at CNH, Kolkata (CAL).Therefore, line drawings and descriptions of these three species are depicted as per protologue and other published literatures. 14,20,22,26The S. subcordata was first collected from Kerala in 1996 and S. linifolia was first reported from India in 1993.Hence, the descriptions and illustrations of Sida linifolia and S. subcordata have been given as per the literature. 22,24As these species are uncommon, chances of being used as adulterant are negligible.

Mericarp of Sida display wide range of diversity
As given in Figure 2 and 3, there are huge diversity in the mericarp of Sida.I came across with 27 different types of mericarps in Sida species.The Flora of India described the awns of Sida alba as convergent whereas in present study awns are found as divergent or convergent or parallel in orientation. 14It is the only species of India which possesses a pair of long awns with antrose hairs and great diversity in awn orientation i.e. divergent or convergent or parallel. 14The Sida cordifolia is easily identified with mericarp morphology, it bears a pair of long awn (more than 1.25 mm) with retrose hairs.Some species of Sida are taxonomically merged or nomenclature is unresolved but they possess unique mericarps: Sida    alnifolia, S. humilis, S. cuneifolia, S. beddomei, S. fryxellii, S. scarbrida, S. glutinosa, S. rhomboidea and S. ravii.

Sida cordifolia and its common adulterants
Sida cordifolia (i.e.Bala) has not shown much diversity like some other species of Sida. 14,19,22Though, Marais was proposed two subspecies from Mascarene Islands but Sivarajan and Pradeep have discarded the subspecies "……………….such a classification seems to be untenable in the case of Indian specimens". 23,27Furthermore, Marais had created subspecies on the basis of flower colour and character state of leaf hairs. 27It means the mericarp morphology is not show much variation in S. cordifolia, which is the key character in the present study.Sivarajan and Pradeep, in Kew Bulletin 45:725-727 (1990), proposed a new record for India as S. fryxellii. 19t is an interesting species, the plant list databases considered the species name as unresolved name; this species has been merged in S. rhombifolia subsp.rhombifolia var.rhombifolia by Flora of India. 14The S. fryxellii and S. cordifolia mericarps morphology are very close to each other except stellate-pubescent awns (S. fryellii) and retrorsely hairy awns (S. cordifolia).This species grows intermixed with S. cordifolia. 23Hence, chance of unintentional adulteration is very high if collector is unskilled or careless.The S. rhombifolia, S. cordata, S. spinosa and S. alba are frequently used as adulterant for S. cordifolia.But all the common adulterants of Sida cordifolia are very different in mericarp morphology especially awns (Fig. 1-3).They are either awn less or possess different awn morphology: two small awns with stellate hairs (S. cordifolia), awnless (S. cordata), a pair of hornlike, small awns (S. spinosa) and a pair of awns, divergent or convergent, hairy, up to 1.25 mm long (S.alba).

CONCLUSION
The mericarp structure shows great diversity in different species of Sida.
It is a key character to determine the identity of the species.The species of Indian Sida may be identified with the help of mericarp morphology.The pharmacognosy of Sida species will be useful for pharmaceutical companies and crude drug research activities.

ACKNOWLEDGEMENT
I wish to express my gratitude to Mr Dinesh Kumar for illustrations.I am grateful to Dr P. V. Prassana, Head of the Office, Central National Herbarium, Howarh, for facilities provided for study.Dr Milind M. Sardesai, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad and Dr Yen-Hsuesh Tseng, National University, Taiwan have helped me with some valuable literatures.I also express my gratitude to Dr H. B. Singh and Dr V. Ranjan and for his valuable suggestions.I thank Dr P Singh, Director, Botanical Survey of India, Kolkata for infrastructure provided during study.