Macodes sanderiana

Macodes sanderiana is a terrestrial orchid with a compact creeping habit. The primary roots of M. sanderiana are fleshy and rarely branch, lateral feeding roots are short and black and are densely arranged on the primary roots. Upright stems are slightly succulent and two to four centimeters high carrying four to six leaves. As stems grow longer, they begin to bend downwards and to explore the forest floor rooting as they grow. In this way the plant can clonally reproduce and colonies can enlarge. Leaves attach to the stem via five centimetres (2.0 in) long petioles which clasp the stem at their base. M. sanderiana has the largest leaves of its genus, they are fleshy and often exceed sixteen centimetres (6.3 in) in length and eight centimetres (3.1 in) in width. Like their petioles, leaf bases also clasp the stem, this is more apparent in developing than mature leaves. Leaves are ovate to elliptic in shape and leaf apices are recurved (bent downwards) and concave whilst the rest of the leaf is convex. The adaxial (upper) leaf surface is the defining feature of this species, it is covered in a complex network of veins. The midrib vein is the most prominent and is surrounded by two other well defined primary veins, all three of which converge close to the leaf apex. …

Macodes sanderiana grows from close to sea-level in low elevation rain forests up to altitudes of at least 800 meters at the lower boundary of the cloud forest. This orchid can grow on a range of substrates which occur through its range. Sander’s orchid is most commonly grown on humus covered rocks near streams and from between rocks in areas where topsoil is almost entirely absent. Despite this orchid usually being described as terrestrial, it is known to grow as a lithophyte in minute crevices in karst cliff faces. Two unspecified species of New Guinean Macodes are even known to grow on trees (possibly Macodes petola or M. sanderiana). As well as growing on substrates with good drainage they also are known to grow in clay soils that never dry out. Sander's orchids are often found growing within moss layers on the forest floor and are known to co-occur with the pacific lychee tree Pometia pinnata. In New Guinea, M. sanderiana flowers annually in July, with each stem producing a maximum of one flower spike. All orchids are known to depend on mycorrhizal fungi for germination and to aid nutrient uptake. Despite this, researchers have been unable to isolate mycorrhiza from M. sanderiana.

Macodes species including Sander's orchid are cultivated for their attractive prominently-veined leaves more so than for their flowers. In 1918, at least three species of Macodes (all native to Malaysia) including M. sanderiana were cultivated in Europe. Despite their initial popularity, by the late 20th century they were rarely seen in collections. Since then, there has been a resurgence in the cultivation of both M. sanderiana and M. petola both of which are now common, especially in smaller private collections. Sander’s orchid requires similar environmental conditions to other terrestrial jewel orchids such as Anoectochilus roxburghii (Wall.) Lindl. and Macodes petola. These species prefer warm conditions and high humidity and can survive in lower light than most other orchids. To provide this environment outside of the tropics they are often grown in terrariums. As the species is terrestrial (unlike most tropical orchids) it can be grown in soil. Many collectors, however, grow this species in shallow dishes of coarse sphagnum moss.

The generic name ‘Macodes’ is derived from ‘macer’ (narrow). The specific epithet ‘sanderiana’ is named after the German nurseryman Henry Frederick Conrad Sander who lived in Hertfordshire and first introduced M. sanderiana to Britain.