Paphiopedilum

**Asian Lady’s Slipper Orchid (Paphiopedilum species and cultivars)**

Colourful Asian lady’s slipper orchids adorn the Angkor Wat replica.

These lady’s slipper orchids belong to the Asian genus Paphiopedilum, affectionately referred to as ‘paphs’ by the orchid enthusiast community! Both the common name and scientific name for the genus derives from the shape of their modified lip petal, resembling the rounded toe of a shoe. Its alliance, the Paphiopedilum alliance, encompasses other genera with flowers that have similarly shaped lip petals, including the genus Cypripedium, which includes hardy species found in the Northern Hemisphere, as well as species in the genera Phragmipedium, Mexipedium, and Selenipedium native to the tropical Americas.

These orchids grow in height with each new leaf (monopodial) and feature fans of folded leathery leaves. The elliptical to lanceolate leaves, which can reach up to 40cm in length and 6cm in width, clasp at the base. Paphiopedilum leaves exhibit shades of green or mottled green and white. Most Asian lady’s slipper orchids produce a single flower on a bare flowering stem arising from the cluster of leaves at the base of the plant. While some Paphiopedilum species and cultivars occasionally produce two or more flowers on a scape, true multi-flowering forms produce multiple buds on an inflorescence, yielding either a sequential succession of flowers where one flower opens after the previous one fades, or a simultaneous display of multiple open flowers.

Floral parts that are obvious from the front view of a Paphiopedilum flower.

Paphiopedilum flowers stand out among most orchids. The dorsal sepal, often the most eye-catching part of the flower, frequently displays distinct markings. The two lateral sepals fused to create a vertical sepal, which can be partially concealed by the lip. Additionally, the lateral petals are elongated, narrow, and may have wavy margins with tufts of hairs or warts which mimic aphids. The lip petal or labellum of the Paphiopedilum resembles a boot and can exhibit either inrolled or outrolled margins. The waxy-textured sepals and petals display a wide range of colours, including browns, greens, whites, pinks, and various mottled combinations.

In the Orchids of Angkor Wat display are the Southeast Asian species Paphiopedilum appletonianum and P. callosum including the hybrid Paphiopedilum Maudiae which is classified under the single-flowered lady’s slipper orchids from the Barbatum section. This section consists of mottled leaf shapes slipper orchids, with flowers borne singly or in pairs that usually bloom once a year and last several months. Their habitat is generally terrestrial, and the plants are usually rooted in leaf litter or humus in shaded forest habitats and are mostly warm-growing species in various parts of the monsoon belt.

Paphiopedilum appletonianum, commonly known as Appleton’s Paphiopedilum, is a fascinating terrestrial orchid native to Laos, Thailand, and Cambodia. The overall effect of specimens blooming from multiple offshoots per plant resembles a flock of birds, with green and copper-coloured flowers often flushed with pink or purple.

Paphiopedium callosum is native to Vietnam, Thailand, southern Laos, Malaysia, and Cambodia. This species is also the pod parent (mother) of the popular primary hybrid, Paphiopedilum Maudiae! It features striking burgundy flowers with white sepals and petals adorned by purple and green stripes. The petals normally sweep backwards, although there is a form which does not. Like many paphs, it has warts and hairs on the flowers which mimic aphids, thus attracting gravid female hoverflies (syrphid flies), its pollinator in the wild, to lay their eggs on the flowers, as their larvae prey on aphids!

In the year 1900, England’s Charlesworth Ltd registered a primary hybrid between Paphiopedilum callosum and lawrenceanum, naming it Paphiopedilum Maudiae. Subsequently, Maudiae became the progenitor of many similar slipper orchid hybrids, exhibiting a wide range of colours—from albino to coloratum (pinks and reds with green accents, sometimes featuring spots) to vinicolor (a deep red wine hue). These Maudiae hybrid varieties are renowned for their exquisite foliage and elegant single (and occasionally two) flowers per stem. The flowers can maintain their perfect bloom appearance for approximately two months!

Little is known about the pollinators of the Asian slipper orchids. While it is suspected that most species of Paphiopedilum rely on hoverflies as their main pollinators. Deceptive flowers, like slipper orchids, which do not offer nectar or pollen rewards to their pollinators, typically have low pollination and fruiting success rates in the wild. These deceptive orchid flowers deceive pollinators in two ways: either by mimicking other rewarding flowers in the area or by imitating non-nectar rewards such as aphids or aphid eggs. These flowers have evolved a clever strategy to attract gravid female hoverflies, which usually lay their eggs in aphid colonies, as hoverfly larvae are voracious eaters of aphids. By featuring aphid-like spots on their petals, the Paphiopedilum flowers effectively lure in these hoverflies for pollination purposes.

Studies also find that the effectiveness of this deceitful pollination strategy is dependent on a combination of visual cues such as warts and hairs, located on the staminode, lateral petals, and sepals, along with specific scent cues. These cues play a crucial role in determining which mode of pollination-by-deceit is employed by a particular species of Paphiopedilum, showcasing the intricate and fascinating ways in which plants have evolved to ensure their reproductive success. Paphiopedilum flowers lasting for one to several months!

While these unique Paphs are still in bloom, explore their exquisite beauty at Orchid Haven in Cloud Forest, set against a replica of the renowned Cambodian UNESCO World Heritage Site, Angkor Wat.

Written by: Ziana Yacob, Acting Senior Manager (Research and Horticulture)

Ziana's fascination with the many wonders of plants led her to study Horticulture. She has been involved in propagating plants and nurturing our in-house orchid collections. Keeping plants alive is a challenge and she's constantly learning about what she should or shouldn't be doing!