Cynorkis boryana var. aristei (J.-B.Castillon) Hermans & P.J.Cribb, Kew Bull. 72(3)-38: 29 (2017).
Homotypic Names:
Physoceras boryanum var. aristei J.-B.Castillon, Richardiana 11: 14 (2010).
Description:
This plant, generally 4-25 cm high, with 1-2 tubers, is most often encountered as an epiphyte on large mossy tree trunks in primitive forest (P. boryanum is almost always terrestrial!) And sometimes even the soil and has one to two green sheaths 0.5-2 cm long at the base. Stem thick 3-4 mm below the leaf and 2 mm higher, about 3-22 cm long and bearing a single stem leaf and 1-2 sterile bracts above. Stem leaf, elliptical on small flowering plants (2.5 x 1 cm) and acute ovate on stronger plants, 3.5-9 x 1.8-3 cm, sheathing on 5-10 mm, glaucous green in color , located a little below the middle of the stem, ie 3-6 cm above the foam mat or the ground. Sterile bracts green, acuminate, 1-2.5 cm long, sheath amplexicaul over 5-10 mm. Sub-capitate raceme of 3-11 flowers distinctly pedicelled, unilaterally arranged on a spine 1-3 cm long. Green floral bract, acute, 10-12 mm long, sheathing at the base about 5 mm. Green pedicel, about 5 mm long and partially covered by the bract. Flower of rather rounded shape, with a diameter of 11-14 mm. Pale pink median sepal, navicular, 6x3 mm, covering the two petals to which it adheres, the three parts forming a helmet covering the gynostemia. Navicular petals, 5 mm long. Labella carrying a purple macule, often decomposed in two at the level of the throat, 1 cm long, with a greater width 12 mm at the ends of the lateral lobes; lateral lobe 6 mm long, 4 mm wide end and barely indented; Median lobe 5 mm long, clearly bilobulate. 4 mm long column. Anther arms 3 mm long. Pink tail, 2 mm long. Hairy ovary, slightly curved, 15 mm long, 2 mm thick and narrowing by 4 mm towards the perianth. Sub-globular spur, green, 2.5 x 2 mm. Fruit, an ellipsoidal capsule, 12 x 5 mm.
Translated from French to English as best I could now
Etymology:
This plant is dedicated to my friend Ariste Rivière de l'Entre-Deux who often accompanied me during my travels.
Habitat:
Found in a forest of the Plaine des Palmistes at 1,400 meters above sea level.
Notes:
The two taxa (typical species and variety) were found in a forest of the Plaine des Palmistes at 1,400 meters above sea level. Two small stations about 300 meters apart have been identified. In the first station studied, the most easily accessible, P. boryanum and its variety coexist but their flowering periods do not overlap: February-March for the variety and May-July for the typical species. The aristei variety is almost always epiphytic and the opposite is true for the boryanum variety. For the leaves surmounted by an inflorescence, I noted, during measurements on a good number of plants, that the ratio L / 1 - where L indicates the length of the leaf and 1 the greatest width of this one ( which is generally a little below the middle of the leaf) - is less than 3 in the aristei variety while it is generally greater than or equal to 4.5 in P. boryanum. The tubers of the variety are generally shorter (3 cm versus 7-10) and less large than those of the species. The number of flowers per cluster does not exceed 11, while it is 10-25 in the typical species. The following characteristics, observed on a large number of flowers of the aristei variety - lateral lobes of the labellum with margins practically intact or even barely toothed, median lobe always bilobulate and not edged -, the fact that the plants flower on different dates and the characters cited above show that these are two plants which are sufficiently different for the new form to be able to legitimately be granted variety status. In very wet locations, P. boryanum plants over 45 cm tall can be found with leaves 20-30 cm in length; this is never the case with the aristei variety, the height of which does not exceed 25 cm, very small flowering plants often being 4 cm high with leaves 2.5 x 1 cm. In the second station mentioned above, which is an area of more humid forests and whose trees are almost always covered with mosses and various lichens, we find plants corresponding to descriptions of the variety, which seems to confirm that we are dealing with two different taxa.
Distribution:
Réunion
References:
Une variété nouvelle, Physoceras boryanum var. aristei (Orchidaceae), de l'île de La Réunion 3 Jean-Bernard Castillon; Bernet, P., 2010. Un nouveau Physoceras (Orchidaceae) de l'île de La Réunion. Richardiana, 10(3) :144-149.; Bosser, J., 1980. Contribution à l'étude des Orchidaceae de Madagascar et des Mascareignes xx - Présence du genre Physoceras Schltr. aux Mascareignes. Un Physoceras et un Cynorkis nouveaux de Madagascar. Adansonia 20 : 257-261.; Richard, A., 1828. Monographie des Orchidées des Iles de France et de Bourbon. Mémoires de la Société d'Histoire Naturelle de Paris , 4 :28, 29 & 80 & planches n°5.
