The Genus Phalaenopsis Subgenus Polychilos
The Genus Phalaenopsis Subgenus Polychilos
David Lafarge Chargé de Mission at Société Nationale d ’ Horticulture de France
T he subgenus Polychilos ( Breda )
Christenson is primarily centered in Indonesia and the Philippines but has a few species distributed as far west as northeastern India ( Christenson ,
2001 ). However , the monophyly of the subgenus Polychilos is not supported by DNA studies ( Tsai , 2011 ). The type species for the subgenus is Phalaenopsis cornu-cervi ( Breda ) Blume . This subgenus is characterized by its fleshy , waxy flowers bearing a pair of calli on the lip . With the exception of P . floresensis and P . micholitzii , most of the species have showy , colorful flowers . One of the remarkable traits of this subgenus is the postpollination greening of the perianth . The petals and sepals turn green soon after fertilization , which might be a way to enhance photosynthates coming from the parent plant to the developing fruit and seeds .
Phyau Shim ( 1982 ) separated subgenus Polychilos from Phalaenopsis as a distinct genus based on Polychilos Breda , Kuhl & Hasselt ( 1827 ) ( Fig . 1 ). This division would require further division of the genus into at least five genera . The broad approach for the genus is followed here ; it seems better to keep these species within the genus Phalaenopsis . The subgenus Polychilos is divided into four sections : Polychilos , Fuscatæ , Amboinenses and Zebrinæ ( Christenson , 2001 ).
Section Polychilos
This section is characterized by flowers appearing sequentially ; a fleshy , flattened rachis ( with the exception of P . mannii ); non-fragrant flowers ; petals narrower than sepals ; a triseriate callus ; a slightly saccate lip base ; a transversely lunate mid-lobe of the lip ; a lip base continuous with the column foot ; and a pair of knee-like projections at the base of the column ( Christenson , 2001 ). Species in this section do not always show
Phalaenopsis - Fourth Quarter , Vol . 22 ( 3 & 4 ) 2012
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5 post-pollination chlorophylly . The finding that section Polychilos is monophyletic ( Tsai et al ., 2006 ), is in agreement with the morphological characteristics of this section . However species in this section , excepting P . mannii , are quite difficult to resolve at the specific level , and are not all satisfying in Christenson ’ s classification . For this reason , other classifications are evocated here . Some micro-variations are sometimes elevated to the specific level , but for the non-specialist , these questions are not really problematic . Phalaenopsis cornu-cervi ( syn . P . cornucervi var . picta ( Hassk ) H . R . Sweet , P . devriesiana Rchb . f ., P . lamelligera H . R . Sweet , P . cornu-cervi var . asamica Mayr , Polychilos cornu-cervi Breda , Polystylus cornu-cervi
Haask .) originates from north India to Java and Borneo at elevations less than 800 m . This taxon is highly variable , with no precise limits , and forms a rather broad complex ( Figs . 2 to 5 ). Plants are epiphytic with thick roots and a rather long stem , up to 10 cm , bearing light green leaves , up to 22 cm long . Inflorescences are basally teres and are quickly flattened . They can produce flowers sequentially over long periods , and should never been cut off before they dry out . Flowers are translucid , yellow , marked with brown spots . Several varieties are described : P . cornucervi f . flava ( Braem ) Christenson ( Fig . 3 ), P . cornu-cervi f . sanguinea Christenson , and P . cornu-cervi f . thalebanii Christenson ( Fig . 2 ). The flava form is usually yellow , but green individuals exist ( P . cornu-cervi ‘ Green ’). Flowers of the sanguinea form are heavily marked with red brown spots and can be encountered under the denomination of P . cornu-cervi ‘ Red ’. The thalebanii form bears larger flowers than the type that are heavily marked with cinnamon spots . This
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