Forest on tops of rocky hills and mountains become shorter and includes in its canopy stratum a number of specific tree species that regularly do not observed on hill slopes. Among them are such species as – Pistacia weinmannifolia, Schefflera pes-avis, Platycarya strobilacea, Myrsine kwangsiensis and Sinosideroxylon sp. Thickets of Dracaena cochinchinensis are common in such habitats, particularly on open rocky outcrops.They give to rocky hill tops very characteristic appearance (Fig. 17). Similar plant communities commonly may be observed on very steep rocky slopes and on cliffs of remnant limestone ridges (Fig. 21-23). Main co-dominants of canopy stratum in such specific primary plant community that cover tops of rocky limestone mountains are listed below in Table 2.
Co-dominant species of canopy and shrub stratum in primary broad-leaved evergreen closed submontane tropical dwarf forests on hill tops in Paphiopedilum canhii native area
1-2 FOREST STRATA
2-10 m tall
PLANT SPECIES NAME
Dracaena cochinchinensis (Lour.) S.C.Chen
Pistacia weinmannifolia J.Poiss. ex Franch.
Schefflera pes-avis R.Vig.
Sophora tonkinensis Gagnep.
Platycarya strobilacea Siebold et Zucc.
Myrsine kwangsiensis (E.Walker ) Pipoly et C.Chen
Many weedy species appears quickly in fragments of primary woods opened by forest fire or logging. They rapidly replace aboriginal primary forest dominants. On first stages of this process in studied area were observed such species as Bauhinia variegata L., Bauhinia sp. (Fabaceae), Clausena sp. and Zanthoxylum avicennae DC. (Rutaceae), species of Callicarpa (Verbenaceae), Euphorbia antiquorum L. (Euphorbiaceae) and some another representatives of secondary plant communities including large woody vines, like Beaumontia pitardii Tsiang (Apocynaceae).
Non-strata (extra-strata) vegetation is well presented in habitats of P. canhii and includes numerous lithophytic, epiphytic, lianas, creeping and climbing plant species, as well as numerous mosses and lichens.
Group of lithophytic plants includes mainly numerous species of ferns and orchids. A number of herbaceous representatives of Begoniaceae (Begonia ssp.), Convallariaceae (Aspidistara sp., Peliosanthes sp., Tupistra sp.), Gesneriaceae (Chirita sp.), Urticaceae (Pilea sp., Elatostema sp.), Trilliaceae (Paris polyphylla), Araceae (Arisaema ssp., Amorphophallus ssp.) and Acanthaceae (Strobilanthes sp.) also belong here. Rosulate, tuberiferous and creeping living plant forms dominate in this group. In primary intact habitats they can develop continuous mats completely covering rocky outcrops on tops of limestone hills and mountains (Fig. 35).
Ferns and orchids also dominate among epiphytic plant communities in habitats of P. canhii. Some tuberiferous epiphytic scandent shrubs, mainly species of Vaccinium, also were observed as typical epiphytes on mountain tops. Epiphytes here often completely cover stems and branches of old gnarled trees (Fig. 36), particularly at the stem base and in tree canopies.
Among epiphytic, creeping, climbing and genuine vines were observed species of Davallia, Pyrrosia,Hoya, Dischidia, Smilax, Stemona, Vanilla, Clematis and few species of Cucurbitaceae.
List of species observed during field works is presented in Appendix 1. All species observations and species records are documented with collected voucher herbarium specimens that are housed at Herbarium of the Center for Plant Conservation of Vietnam Union of Science and Technology Associations (Vietnam, Hanoi) with duplicates delivered into main World Herbaria.
CHARACTERISTIC OF PAPHIOPEDILUM CANHII HABITATS Shady vertical cliffs of N, NE and NW exposition on steep rocky slopes of remnant limestone hills and mountains covered with intact primary broad-leaved evergreen forest were observed as typical habitat in all discovered subpopulations of Paphiopedilum canhii (Fig. 24-34). Discovered subpopulations of P. canhii in its native area were observed at elevation 950-1200 m a.s.l. The species grow in upper part of hill slopes, just on high vertical cliffs, usually in 40-60 m below hill tops. However, occasionally it almost reaches mountain summits growing here in shady humid crevices. Plants regularly grow as a typical rosulate lithophyte on rough solid vertical walls covered with scattered mosses in permanent humidity and in constant shade provided by intact canopy stratum of primary forest. Very often roots of plants adpressed to just solid unbroken limestone wall using no any fissures or holes. Remnants of primary forest supporting populations of P. canhii in all its discovered populations was observed as a still intact, but very endangered units threatened by expected coming logging (Fig. 24-34).
In fact, P. canhii grows in very similar natural, environmental and climate conditions, which were described in details for Paphiopedilum coccineum (P. barbigerum var. coccineum) in our early publications (Averyanov et al., 2003, 2004).
Numerous lithophytic ferns and orchids are most usual cohabitants directly associated with P. canhii in its native habitats. Observed species of this group are listed below.
Most usual lithophytic associates of P. canhii in its native habitats
It is remarkable that sometimes P. canhii grow just together with other slipper orchids, such as P. concolor and P. dianthum in close proximity to populations of P. barbigerum (var. coccineum) and P. malipoense that theoretically provide possibility for their natural hybridization.
OF ITS PRESENT STATUS In current completed investigation, Paphiopedilum canhii was discovered in five subpopulations settled in small isolated limestone area in square less than 0.5 km2. The formal area of probable species occupancy is even smaller and may be formally estimated (according to methodology recommended by IUCN) as polygon with square about 0.35 km2 (Fig. 56). In fact, actual original square occupied by species growing on vertical cliffs is certainly less than few hundred meters. Total number of specimens in all five subpopulations before commercial collecting may be estimated presently very approximately, but most probably the plant number was approximately 10.000-15.000 mature (flowering-size) samples. There exists certain evidence that five discovered subpopulations represent all existing area of P. canhii. Plants in their natural habitats grow as a rosulate lithophyte forming on vertical shady walls before commercial collecting more or less dense intact colonies, each with 10 to 50 mature and juvenile samples spreading commonly on square 1-2 m2. Little time ago, many such colonies were scattered on a numerous high cliffs in studied locality, as it may be seen on Fig. 37-39. However, even at this time, before commercial exploitation number of specimens and total species area in each subpopulation was miserable.
Regrettably, all discovered subpopulations to the moment of our exploration and studies were already tragically depleted by commercial collecting. In our studies already during December 2010 was found no one intact colony. Absolute majority of colonies in all 5 subpopulations were extinguished completely and only occasionally in most inaccessible cliffs were observed poor remains in form of single commonly depressed or juvenile specimens (Fig. 48-55). Plants were exactly collected just recently, certainly few months before our December studies and many cliffs still retained numerous sad traces of former majestic species abundance. Very rarely few remained mature plants were observed in places of former many-numbered colonies. Proportion of such plants may reach 30% (Fig. 55). However, this is alone observed example. In all other cases, plants are eliminated from colonies on 99 to 100% (Fig. 51-54). Total extinction of plants during 2009-2010 year may be estimated as at least 99%. At the same time, the number of surviving mature (flower-sized) specimens in all subpopulations hardly exceeds presently 0.01% of former species population. Such unique relicts are presented on Fig. 37-50. As commercial collecting still cannot be stop immediately, these are, probably, last photos of P. canhii in nature.
On the base of available data and current original observations Paphiopedilum canhii may be estimated presently in IUCN terms as critically endangered species (CR), which is facing an extremely high risk of extinction in the wild in nearest future.
TAXONOMY, MORPHOLOGY AND BIOLOGY OF PAPHIOPEDILUM CANHII Paphiopedilum canhii was described by Prof. Leonid Averyanov and Mr. Olaf Gruss in 2010 on the base of few specimens of uncertain origin collected (as to be said) supposedly in Son La Province and flowered in Hanoi in private orchid collection of Mr. Chu Xuan Canh in March 2010. It is most probably that locality of the type was not indicated in description properly, being based on talks of local dealers which is commonly very far from scientific accuracy. Later project participants in Dien Bien Province found the species. Extensive wide searches of P. canhii outside this discovered area in Vietnam and Laos bring no positive results. Now this species may be certainly regarded as local Vietnamese endemic with very restricted distribution in Dien Bien province of NW Vietnam.
First publication of new species with illustrations and description appeared in May issue of American Orchid Society Magazine (Orchids) that immediately introduced species to broad circle of orchid lovers all over the world. Unfortunately, published name cannot be regarded as valid due to superfluous citation of two elements as a nomenclature type (Art. 8.1 & 8.2 of ICBN). A month later, the species was described in full accordance with rules of botanical nomenclature in Russian scientific journal - Turczaninowia (Averyanov, 2010). Both presented publications contained extensive data on morphology and nature of described plant. Primary observations and additional studies of this species in nature confirmed very isolated position of this plant in the genus Paphiopedilum that was already mentioned in previous publications (Averyanov, 2010). This statement initiated description of new monotype subgenus - Megastaminodium Braem et O.Gruss (2011, Ochid Digest, July, Aug., Sept.: 164). Actually P. canhii has indeed morphologically more or less intermediate position between species of section Parvisepalum Aver. et P.J.Cribb (subgenus Parvisepalum Karas. et Saito) and section Barbata (Kraenzl.) V.A.Albert et Boerge Pett. (subgenus Paphiopedilum). It undoubtedly deserves segregation in rank of separate supra-species taxon. However, we suppose that will be more reasonable regard such taxon in rank of section of type subgenus. Description of such section is proposed here. It accompanied with key to identification of Paphiopedilum infra-generic subdivisions.
Standard taxonomic citation of P. canhii and its taxonomic position are listed below. Also, below are presented corrected and improved description of the species with addition of all obtained original data on its morphology, ecology and phenology (Fig. 57, 58).
Key to subgenera of the genus Paphiopedilum Pfitzer 1. Median sepal more or less similar to petals in shape and color; petals broadly-ovate to circular, less than twice as long as broad . . . . . . . . . . 2
+. Median sepal distinctly differs from petals in shape and color; petals much narrower than dorsal sepal, tapering, narrowly-oblong or spatulate, more than twice as long as broad . . . . . . . P. subgen. Paphiopedilum
2. Median sepal distinctly smaller than petals; lip inflated, more or less spherical, thin-textured, lightly grooved along the veins; staminode large, broad at apex, flat or longitudinally conduplicate; flowers white, pale yellowish-green or pink, sometimes with brown or purple stripes along nerves; leaves tessellated or uniformly green . . . . . P. subgen. Parvisepalum Karasawa et Saito
+. Median sepal more or less similar with petals in size; lip is ovoid, rather thick in texture, plain on surface; staminode middle sized, distinctly 3- or 5-dentate at the apex, with a large narrow central tooth; flowers white to pale yellowish, sepals and petals usually with small purple spots; leaves always tessellated . . . . . P. subgen. Brachypetalum (Hallier) Pfitzer
Key to sections of subgenus Paphiopedilum 1. Lip inflated, sub-spherical, calceolate, thin-textured, slightly grooved along the veins; staminode large, broadly ovate, broad at apex, flat; leaves usually 4-7(8) cm long, very rigid, markedly tessellated above, heavily purple-violet spotted below; plant of calcareous substrate. . . . P. sect. Pygmaea Aver.
+. Lip goblet-like, cylindrical, leathery, glossy, not grooved along veins; staminode middle sized, various in shape, with obtuse or dentate apex, often with central umbo; leaves commonly longer than 8 cm, not much rigid, soft or leathery, uniform green or tessellated; not purple spotted below, or with few scattered purple marks at the base; plant of calcareous or acidic silicate substrates . . . . . . P. sect. Paphiopedilum
Described from NW. Vietnam (“NW. Vietnam, Son La prov.”). Holotype(“Chu Xuan Canh CXC 101, 14 Nov. 2009”, in fruit) – HN; epitype (“Phan Ke Loc HAL 12907 22 March 2010”, in flower) – Herbarium of The Center for Plant Conservation (Hanoi).
Description.Lithophytic sympodial rosulate herb with (2)3-4(7) leaves. Leaves elliptic to oblong, 3-7(8) cm long, 1-2(2.5) cm wide, slightly emarginate and shortly apiculate at the apex, markedly tessellated light and dark green above, pale green and heavily marked with dark dirty-violet below. Inflorescence erect, 1-flowered; peduncle slender, 3-6(10) cm long, dark green, sometimes with dirty-purple tint, pubescent with dirty olive-violet hairs. Floral bract narrowly ovate-elliptic, acute, (0.8)1-1.2(1.4) cm long, 3-4(5) mm wide, green, olive-violet pubescent. Flowers 6-8 cm across. Dorsal sepal ovate to broadly ovate, acute; 1.5-2.5(3) cm long, 1.4-2 cm wide; white, slightly greenish at the base, in lower half veined with 5-11 purple nerves; densely hairy outside. Synsepalnarrowly ovate to ovate, acute; 1.4-2.2 cm long, 0.7-1.4 cm wide; light uniformly dull green to white, occasionally with 2 purple stripes; hairy outside. Petals 2.8-3.5(4) cm long, 0.5-0.7 cm wide at the base, spreading, more or less horizontal, cuneate, narrowing from broad base to elongate, acuminate apex, background light green to pinkish-green, brightly deep green toward base, dull purple-violet to the apex, with 7-9 dark purple-violet longitudinal stripes along nerves, long white ciliate along irregularly slightly undulate margin. Petal base with dense tuft of long, glassy, pellucid, dark violet papillae at lower margin faced to lip entrance. Lipslipper-sac-like; (2)2.5-3.5 cm long, (0.8)1-1.5 cm wide, light dull green, with light brownish-purple tint on smooth and glossy incurved side lobes; inside at the base densely haired with long white glassy pellucid papillae, dark violet at apex. Column short and broad, 3-4 mm long, light greenish to brightly green. Stamens with elongate obtuse filament apices; filaments light greenish to green; anther spherical, yellow to orange; pollen yellow-orange, viscid. Stigma hemispheric, white to light greenish, 4-5 mm in diam. Staminode large, (8)10-12(14) mm long, (5)6-9(10) mm wide; entire, glossy, broadly ovate to ovate-elliptic, flat, hardly indistinctly emarginate and grooved at apex; white to light greenish, with irregular washy yellowish-green to dark green marks. Pedicel and ovary 1.5-2.5(3) cm long, dark green, densely pubescent with dirty olive-violet hairs. Fruit dry, narrowly ellipsoid, ribbed, shortly beaked capsule about 2-3(3.5) cm long and 4-5 mm in diameter. Fig. 57, 58.
Ecology. Broad-leaved primary shady humid forests on rocky limestone at elevations about 900-1200 m a.s.l. Obligate lithophyte on vertical shady limestone cliffs near tops of ridges, with roots adpressed to solid vertical walls having no soil. Fl. March - April. Fruits August – September. Extremely rare (CR).
Distribution.Vietnam (Dien Bien Province). Endemic.
Note. Samples of P. canhii bloom in nature in March-April. Fruit formation is rather low. Very few samples developed fruits (probably less than 10%) according to observation in 2010-2011 years. Capsules are rather small. They ripening and disperse seeds commonly during August-September.
One or two small additional bracteoles are often observed on inflorescence apex at the base of floral bract. They probably indicate existence of rudimentary flower bud that gives evidence of possible potential formation on inflorescence of two flowers.
HISTORY OF EXPLOITATION AND EXTINCTION OF PAPHIOPEDILUM CANHII Hard exploitation of Paphiopedilum canhii started immediately after its discovery in middle of 2009 year. The species was at first found by H’Mong (Meo) local minority people and collected along with other orchids for their routine sale in local markets of Dien Bien and Son La cities. Very distinct unusual slipper orchid was highly valued by local orchid lovers and fanciers just immediately after its appearance in orchid market. In few weeks, rumours on intriguing new species spread widely reaching Hanoi and other large cities of northern Vietnam. First flowers of mysterious plant were open at the beginning of 2010 in a number of private collections in Hanoi, Dien Bien and Son La cities. At this moment, become clear that orchid society met one more new exciting slipper orchid species. Next days internet was filled with images of new flower.
At this time price for flowering plants reached its maximum. Illustrated publication of new species in world-known American Orchid Society Magazine also activated market demands and supported fast cost rise. Additionally, participation in the trade of foreign dealers provided much highest influence to the market price dynamics. Numerous international dealers arrive in spring 2010 to Son La and Dien Bien cities for trading. Best plant clones at this time were traded by costs up to 100 USD for alone plant. Largest lots of plants were supposedly imported into Taiwan.
Exciting rumours about high prices for plants provoked true orchid fever in the area of Paphiopedilum canhii. All local people from neighboring village’s layaway their each day home duties and come to the forest looking for plants. In some days, more than 20 people collected plants in dream to sell them for high price. Naturally, high supply of plants on the market for sale, rapidly exceeded demands. Very soon, just after plant flowering period price come dramatically down to 100 and then 50 USD per kg. To the end of 2010, the cost was only 10-20 USD for 1 kg, but even for these costs, trade was very weak and nearly all not sold plants were simply trashed. Ironically, the collecting of great majority of plants from nature was reasonless. They bring no money to local people, no profit to local or international trade, no happiness to orchid lovers all over the world. These last specimens of unique critically endangered species that stands on verge of full extinction were simply wasted (Fig. 167). Low level of horticulture and lack of necessary experience in slipper orchid cultivation permit no long cultivation of P. canhii in local collections and nurseries. So even large flowering size plants actually have no chance to survive in conditions of primitive agriculture (Fig. 167-170). To the end of 2010 trade of P. canhii actually completely exhausted due to 3 main reasons: - no more demands from foreign dealers (they already bought best clones necessary for propagation and breeding); - no more demands from domestic purchasers (due to difficulties in plant cultivation in poor conditions); - very few plants in nature (that make their search and collecting almost unprofitable).
According to very approximate estimation 25-35 kg of P. canhii samples were collected during short history of its discovery, exploitation and extinction. Plants are fairly small when 1 kg contains about 300-350 mature (flowering-size) plants and commonly 200-300 offspring juvenile samples. Following to these calculations totally were collected at least 10.000-15.000 mature and juvenile specimens. Direct observation in nature indicates that about 99.5% of populations were extinguished in half of year of exploitation. In our opinion species has very few chance survive in nature. It is particularly true taking into consideration fast deforestation in its small native area. Cultivation under appropriate conditions in high technology nurseries may prevent full species extinction. However, such activity de jure is illegal due to CITES regulations. No one CITES export permission for P. canhii was ever processed and all samples of the species outside Vietnam are still actually outlaw originating from illegal black market.