Deceptive petals: 7 orchid mimics

Like the Genovese and the Gambino, the Orchidaceae are an intimidating family. With about 25,000 species, it's also the largest family of flowering plants. This does not make it any easier to identify a member, however. So let me ask you: how do you know when a flower is an orchid? Most people will probably answer, 'you can tell by the differently coloured lip'. This would be a mistake. Many plants with brightly coloured lips aren't orchids at all. Many others just have a gestalt that screams 'orchid' in hot pink tones, but you'd be wrong again. Botany is sometimes confusing. Let's take a look at a few examples of flowers that seem to mimic those of the orchids.

Bauhinia blakeana [Fabaceae - the Legume family]. It's easy to see why this is called the Hong Kong orchid tree, for the resemblance to an orchid blossom is rather striking. In 1880, Sir Henry Blake - then British Governor of Hong Kong and a keen botanist - discovered the plant growing near the ruins of a building on the shore of Pok Fu Lam. It has since become the floral emblem of Hong Kong. A popular tree for highway medians and parking lots in hot cities, it's large heart-shaped leaves make it attractive even when out-of-bloom.

Alpinia zerumbet [Zingiberaceae - the Ginger family]. Many members of this gorgeous plant family produce flowers that appear orchid-like, complete with glowing lips in the correct, lowermost orientation. Unlike orchid flowers, those of ginger do not possess a column, the central structure formed from the fusion of male and female parts. Shell ginger is a good example. This Chinese evergreen rapidly forms large clumps of lush tropical foliage when grown in frost-free areas with partial shade.

Tacca chantrieri [Dioscoreaceae - the Yam family]. After seeing the diverse array of black orchids out there, it is tempting to classify this sinister thing as an orchid. The bat flower, as it is affectionately known, actually belongs to the plant family that includes yams and other herbaceous vines. What appears to be large, darkly coloured petals are in fact involucral bracts, and not floral structures at all, just like the festive red 'petals' of the poinsettia. The real flowers are the cup-shaped structures within, surrounded by distinctive whiskers. If you can grow Phalaenopsis orchids really well, this Malaysian terrestrial should be well-suited to your conditions: it likes shade, high humidity and good air circulation.

Zingiber spectabile [Zingiberaceae - the Ginger family]. Another ginger species, the beehive ginger should not be confused with the related Z. officinale, the beloved culinary ginger. The plants grow quite tall, with the inflorescences typically carried beneath the attractive foliage. The beehive structure of the flowerhead is - once again - formed from colourful bracts, with the orchid-like flowers themselves appearing from between these. Gardeners and florists have many varieties to choose from, with flowerheads in orange, pink, yellow, red and several bicoloured combinations.

Strongylodon macrobotrys [Fabaceae - the Legume family]. The jade vine produces pendant clusters of totally unique aquamarine flowers. Once you've walked under a pergola festooned with these, the watery blooms of a wisteria seem positively wistful by comparison. It's not only the Orchidaceae that produce flowers of unusual colour, it seems. The jade vine hails from the Philippines, that trove of botanical marvels, where its blooms are visited by rainforest bats. It was first collected in 1854 on Mount Makiling on the island of Luzon by botanists of the U.S. Wilkes Exploring Expedition. Perhaps not surprisingly, it is now exceedingly rare in the wild and faces threat from deforestation.

Catalpa speciosa [Bignoniaceae - the Jacaranda family]. Just as orchids are not confined to the tropics, so orchid mimics can be found in virtually every environment. The Northern catalpa is a deciduous ornamental tree from the United States, orginally found along the Mississippi River basin, but now naturalized throughout much of the Midwest and considered invasive in places. It is known by several names in the vernacular, cigar tree and Indian bean being the most common, refering to the long, slender pods formed in mid-summer after flowering. The showy flowers bring to mind those of a unifoliate Cattleya, being large, white, ruffled and with distinct streaks of colour toward the interior.

Elettaria cardamomum [Zingiberaceae - the Ginger family]. Cardamom is a giant among gingers, growing to a height of almost 4 m. By contrast, the inflorescences are minute and held close to the ground, bearing several small blossoms. It grows wild in moist forests of the Western Ghats on India's Malabar Coast. An expensive spice, cardamom needs to be hand-picked daily at the moment of perfect ripeness. Few gourmands realize that the cardamom they praise so highly for the beauty of its aromatic fragrance has equally beautiful flowers. These blossoms are truly deserving of the moniker 'orchid-like'.

As we have seen, pretty petals do not an orchid make. So what is an orchid, and what isn't? This question can be answered most decisively by genetics. Simply put, an orchid is any member of the family Orchidaceae. Like the New York crime families, it's an exclusive club; they don't allow just anyone in and it doesn't matter if you look the part. However, in lieu of having a full-fledged genetic fingerprinting lab at your disposal the next time you're poking around your favourite nursery, remember that orchids usually exhibit these characteristics:
∙ a prominent lip (labellum) different from the other petals and sepals
∙ resupinate flowers twisted through 180°, leaving the lip lowermost
∙ pollen formed into sticky masses called pollinia
∙ a column (gynostemium) composed of both style and stamen
∙ fruit in the form of dehiscent capsules
∙ very small, almost dust-like seed
∙ close associations with mycorrhizal fungi
And then remember that there are exceptions to almost all those characteristics. Good luck...


Photography credits: Bauhinia blakeana © Christoph Diewald; Alpinia zerumbet © Avelino Maestas; Tacca chantrieri © Julia; Zingiber spectabile © Tony; Strongylodon macrobotrys © David Midgley; Catalpa speciosa © Cindy Ware; Elettaria cardamomum © Gopu P. Please visit these exceptional Flickr users for more floral excellence.