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Introduction
Microdracoides squamosa Hua. is a sedge plant species belonging to the Cyperaceae family (1). It is the only species in its genus Microdracoides, making the genus monotypic (1).

First described in 1906 by Henri Hua, the species is endemic to areas of tropical West Africa with confirmed native populations in Cameroon, Guinea, Sierra Leone and Nigeria (2). Some populations believed to be found in Equatorial Guinea. However, these are yet to be confirmed (2).

Populations of M. squamosa are frequently observed to grow in high altitude habitats such as cliff outcrops and mountainous terrain (1). This habitat has conditions similar to dry arid habitats due to the long periods of drought, frequently high temperatures and intense sunlight (3). The substrate of these areas is usually granite or sandstone with other species present usually being other low-lying shrubs (4).

The species has scales lining the thickened stem and small thin leaves arranged in a rosette (1). The species flowers every year (perennial) with individual plants having separate male and female sexual organs (dioecious) (4).

Description
M. squamosa Hua has been observed to grow to 100cm forming branches which can grow several cm in diameter (4). The species has a swollen specialised stem called a caudex that can grow new roots and shoots (rhizome) which are visible above the ground (5). The caudex of M. squamosa is tree like (arborescent) in structure which differentiates its appearance from other plant species with similar adaptations (5). Around the caudex of M. squamosa, there are small squared scales which are white/light brown in colour. These scales are the base of old leaves and their sheaths which are left behind during the growing process (4,5).

The leaves of M. squamosa are arranged in rosette at the top of stems with leaves wide at the base becoming narrow and thin, akin to species belonging to Pinus (1,4). Leaves are described as 1-5cm in length, deciduous and light green in colour with older leaves being located on the outside (brown) (1,4). Due to the small, thin leaves and the structure in which they grow, younger forms of M. squamosa could be easily misidentified as a large moss species on initial observations (6).

The inflorescence of M. squamosa (a structure containing multiple flowers) is a spike measuring up to 40cm with small and simple flowers (1). Arranged in a spikelet which consists of modified small leaf membranes which are found beneath the flower (glumes) and several small flowers (florets). The spikelets are found in an alternating pattern on the main spike and are attached directly to the base (sessile) (4). Male flowers measure 5-8mm and contain 3 stamens whereas female flowers measure 5-4mm and contain pistils surrounded by 3 feathery scales (1). The fruit of M. squamosa appears as a small nut known as a nutlet (achene) and is cylindrical or sometimes angular in shape (7). The nutlet is smooth in texture with the internal seed almost filling the nutlet shell (4). The nutlet has also been observed to have basal hairs present on the base (7). These basal hairs are an adaption which allows long-distance dispersal of the seed via wind (7).

Etymology
The name Microdracoides squamosa was first published by Henri Hua in (1906) (4). The genus name Microdracoides is made up of ‘micro’, a word which originates from the Latin word ‘mikros’ meaning small or little and dracoides, formed by the Latin word ‘draco’ meaning dragon or serpent (Stearn and Smith, 2002). This name represents the height of the species combined with the clothed scales which are present on the caudex of M. squamosa (Stearn and Smith, 2002). The species name squamosa is derived from the late Middle English word ‘squamous’ which can be traced to the Latin word ‘squama’ meaning ‘fish scale’ (Stearn and Smith, 2002). This word is given to further describe the shape and arrangement of the small scales present on caudex tissue (1).

Habitat and ecology
M. squamosa is confined to the outcrops of rocky slopes and mountains of tropical West Africa with most populations being observed in altitudes of over 200 metres (1). The outcrops in which M. squamosa are located are composed of granite or sandstone and have unique environmental characteristics (3). The factors which have the most influence on the diversity of species found on these outcrops are the temperature, low water availability and soil type (3).

Distribution
M. squamosa has been observed in several locations within tropical West Africa to Cameroon. The species has been observed to occur in Cameroon, Nigeria, Guinea, Sierra Leone with literature reporting observations in Equatorial Guinea however these are not currently verified (2). M. squamosa populations are found primarily on rocky outcrops and large mountains structures surrounded by flatland known as inselbergs (9). Populations are only reported to grow on particular soil types, notably those which are sandy or those which contain clay with increased humus content (9).

Taxonomy and Systematics
M. squamosa belongs to a monotypic genus due to its unique characteristics and environment which have caused complications for its placement in subfamilies and genera of Cyperaceae (1). M. squamosa has also been named Schoenodendron buecheri by Engler in 1910, however, this synonym is not accepted (11). The placement of Microdracoides has had a history of placement issues as it shares characteristics with the tribe Lagenocarpeae due to shared phylogenetic traits with the genus Trilepis Nees and Coleochloa Gilly (1). However, there are differences between the genera particularly between the habitats and M. squamosa showing well-defined petals and sepals (perianth) (1).

Other authors such as Hutchinson, placed only Microdracoides and Trilepis in Cryperaceous (currently Lagenocarpeae) and then later withdrew Microdracoides due to the genus being one of “doubtful position” (1). The separation of Microdracodies from Lagenocarpeae by Hutchinson was based on the species’ unique habitat, the arrangement of its leaves and the formation of two separate sexual organs on each individual organism (1).

M. squamosa has also been placed into the tribe Trilepideae by Goetghebeur in 1985 based on its embryonic and particular features of its flowers (7). Based on literature by Goetghebeur Trilepideae consisted of 4 genera including Afrotrilepis J.Raynal, Coleochloa Gilly, Trilepis Nees and Microdracoides Hua. These genera were grouped by Goetghebeur as they all shared the characteristic of having unique inflorescence and embryonic structures (7). The embryonic structures identified to be similar across these 4 genera were: the embryo having a specialised root (cotyledon) which was tubular and flattened, a lateral specialised seed stem (plumule), and a pronounced sheath protecting the emerging stem of the seed (coleoptile) (7). The inflorescence (flowering shoot and flowers) of these 4 genera were grouped based on spikes being arranged in bunches along the axis of flowering shoots with the spikelets being packed together (7). Following this grouping, Trilepediae was placed into the subfamily Scleroideae, which is now rejected and instead placed into the subfamily Cyperoideae. The key characters which place M. squamosa within Cyperaceae are the presence of leaves growing in tufts from a rhizome (cauline) (5). Another characteristic of a sedge is if flowering shoots and flowers (inflorescences) emerge from these tufts and are alternately covered in spikelets surrounded by specialised leaves (bracts) (5). The characteristics which separate Microdracoides from other genera of Cyperaceae is the occurrence of the scales which are present on the stem being square and the presence of silicon in the innermost fibers of the nutlet wall (5, 7, 12).

Additional information
The roots of M. squamosa have adaptations which allow survival during drought conditions. The inside of the roots contain an outer layer of empty cells called Velamen (10). These cells are often found in members of Orchidaceae and aid in water absorption (10). The presence of these empty cells in M. squamosa allow rapid water uptake in the roots, due to high temperatures and high levels of water run-off (10). The occurrence of the large caudex structure allows rapid regrowth if the plant roots or leaves are damaged (5). The areas of tropical West Africa where M. squamosa are found occasionally experience forest fires, suggesting the caudex is present to allow regrowth in these situations (13).