An identification system for plants of the NT arid zone:
A pictorial key to groups of trees, shrubs, vines and forbs of the MacDonnell Ranges Region
Main Dicot Key Lucid
Flowering plants of dryland situations; perianth parts never fused together into a cap that falls at anthesis; perianth parts either readily recognisable, much reduced and parts not easily counted or rarely completely absent; leaf blades (when present) with a single midvein (with or without lateral veins), netted venation or palmate venation, OR if veins not discernible with a hand lens then leaves not sheathing; if leaf blades completely absent then bladeless sheaths also absent; sporocarps, scale leaves and cones absent; growth form not palm-like or grass-like.
Eucalypts and Corymbias Lucid
Perianth parts (i.e. sepals and/or petals) that are 1) fused together into a cap (sometimes also a smaller second cap present) that 2) eventually falls from the mature flower bud 3) exposing numerous stamens; trees or mallees rarely less than 2 m high with woody capsular fruit and leaves that typically give off an eucalyptus odour when crushed.
Casuarinaceae (2 species)
Scale leaves in whorls of 4-17; scale leaves soon turning straw-coloured or brown and contrasting with the greener branchlet internodes; branchlets lacking a resinous (coniferous) odour when crushed; female fruiting cones barrel-shaped with numerous projections in longitudinal lines; trees of sand plains, dunefields and disturbed watercourses near Alice Springs.
The terminal expanded leaf on each branchlet with a sheath-like stipule that completely encloses the growing shoot prior to falling; stipules leaving an obvious scar that encircles the stem when they fall; sap milky; flowers and fruits numerous but highly modified and never exposed, being borne on the inner surface of a fleshy globular receptacle or false fruit.
Perianth Monocots Lucid
Perianth conspicuous, six parts readily counted sometimes with the aid of a hand lens) though rarely (Commelina) one very conspicuous and five less obvious, all petaloid (white, yellow, blue, pink or purple), all sepaloid (green and transluscent turning straw-coloured), or differentiated into sepals and petals, the longest >2 mm long or if rarely less then leaf auricles absent and anthers with filaments; leaf blades (when present) with 3-many parallel longitudinal veins OR if veins not discernible with a hand lens then the lower part of the leaf partially or fully sheathing (encircling) younger inner leaves and/or the flowering stem; if leaf blades completely absent then base of the flowering stems encircled by bladeless sheaths.
Grass Trees (Xanthorrhoea thorntonii) Factsheet
Leaves linear, less than 5 mm wide, undivided and with entire margins, broadening at very base and partially sheathing (encircling) the stem, borne directly on each main stem/trunk, the live ones crowded at the apex of each stem/trunk.
Palms (2 species)
Leaves fan-shaped with incised margins, borne directly on each main stem/trunk, the live ones crowded at the apex of each stem/trunk (Livistona mariae) Factsheet , or if pinnate then most leaflets distinctly folded along their length (Phoenix dactylifera) Factsheet and sometimes splitting along the midvein towards the base; flowers (and fruits) sometimes clustered but never aggregated into cones.
Typha domingensis Factsheet
Inflorescence a distinctive dense cinnamon-brown elongated spike, divided into two parts with a small gap between them, the upper male portion and lower female portion; robust perennial (to > 2 m) of wetlands.
Eriocaulon (2 species)
Flowers and fruits densely packed into a solitary ovoid or hemispherical white to dark grey head 3-6 mm wide terminating each peduncle; heads surrounded by several sterile bracts shorter than the heads; peduncles with an obliquely mouthed bladeless tubular sheath at the base; small annuals (less than 15 cm high) with transverse septa in the leaves and capsular, 3-lobed fruit containing 3 seeds.
Triglochin (4 species)
Perianth present though small (<2 mm long) and quickly deciduous; anthers sessile and each falling with a perianth segment; tiny leaf auricles present though ligule absent; fruit finally separating into segments corresponding to the three fertile carpels, the carpels with basal spurs or appearing 6-pointed when viewed dorsally; small annual wetland plants.
Centrolepis (2 species)
Terminal cluster of flowers fully or partially enclosed by a pair of prominent erect sheathing bracts; leaf sheaths with free margins; tiny fruits splitting to release a single seed; small annuals to 6 cm high.
Aquatic plants confined to semi-permanent or permanent water bodies with comparatively stable water level; all leaves fully submerged below water surface or some leaves floating on water surface, rarely a few extending just above water surface.
Typical Ferns Lucid
Young leaves coiled from tip downwards and unfurling as they expand; sori (clusters of spore-bearing sporangia) present on the underside of mature leaves (check several leaves including the most mature)
Plants never producing flowers but with spore-bearing sporangia embedded in swollen leaf bases.
Leaves with a long stalk terminated by four leaflets (resembling a 4-leaf clover); wetland plants never producing flowers but with spore-bearing sporangia enclosed in purse-like structures (sporocarps) at the base of the plant (3 species).
Psilotum nudum Factsheet
Plants never producing flowers but with spore-bearing sporangia fused into a stalkless 3-lobed fruit-like structure in the axils of 2-lobed scale leaves; sterile leaves (i.e. those not bearing sporangia in the axils) scale-like and unlobed; uncommon plant restricted to moist shaded rock crevices.
Plants never producing flowers but with spore-bearing sporangia borne in stalked narrow terminal spikes, the whole structure resembling a small spear; leaves generally few, lanceolate, ovate or elliptic with netted venation.
Gymnosperms and Conifers
Cycads (Macrozamia macdonnellii) Factsheet
Leaves pinnate, borne directly on each main stem/trunk, the live ones crowded at the apex of each stem/trunk; leaflets flat or slightly concave at base, never splitting; reproductive structure a cone.
Cyprus Pine (Callitris glaucophylla) Factsheet
Scale leaves in whorls of three; scale leaves and their decurrent bases (that completely cover the internodes) the same colour; branchlets with a resinous (coniferous) odour when crushed; female fruiting cones globular with six woody scales; tree of rocky hills and ranges.