Lophiaris silverarum Carnevali & Cetzal, 2014

Lophiaris silverarum Carnevali & Cetzal View in CoL , sp. nov. ( Fig. 1 View FIGURE 1 )

A species of Lophiaris related to L. crispiflora and L. carthagenensis but easily distinguished by its larger flowers (25–30 mm diameter across the spread dorsal sepal and labellar apex) that are straw-yellow colored with non-confluent, laxly arranged pale reddish-brown spots.

Type:— PANAMA. Veraguas: Distrito de La Mesa, Palo Verde, Río Subí, Costa Pacífica , 8°13'N, 81°10'W, approx. 180 m, December 2005, vegetación primaria a orillas del río, Silvera & Rodríguez s.n. (holotype: PMA! GoogleMaps ; isotypes: AMES! GoogleMaps , CICY! GoogleMaps ).

Epiphytic erect herbs, shortly creeping to cespitose; rhizome short, thick; roots 2–4 mm wide, white; pseudobulbs 8–10 mm long, 17 mm wide, subcylindrical to broadly ovoid, apically 1-leaved, totally enclosed by 3 imbricate sheaths; leaves 15–47 cm long, 3–10 cm wide, thickly fleshy coriaceous, conduplicate, entirely green but paler toward base, some extremely faint pale purple mottling evident in the underside of a few leaves, oblong-elliptical, thickly fleshy-coriaceous; inflorescences solitary from the base of the pseudobulbs, 79–94 cm long, a 15–110- flowered panicle; peduncle and rachis green, darker towards the base, peduncle somewhat erect to arching; bracteole minute, triangular and acute; flowers resupinate, sepals and petals straw-yellow colored, the whole surface lax and heterogeneously covered with non-confluent pale reddish-brown spots, 0.7–1 mm diameter, the claws paler and those of the petals lacking spots, labellum same colored but with denser spotting (and spots confluent) on the midsection of the lateral lobes, disc darker straw- yellow, callus pale straw-yellow with pale reddish-brown spots on top of the teeth, column pale yellow, the ventral surface darker and with confluent pale redbrown blotches; the stigmatic surface dark red-brown, the column wings pale pink; the anther white or exceedingly pale pink; flowers 25–30 mm diameter across the spread apices of the dorsal sepal and the labellar apex, with perianth parts widely spreading and with undulate margins, the petals and sepals somewhat reflexed; ovary with pedicel 25–30 mm long, 0.9–1.2 mm thick; sepals basally clawed, spreading or somewhat reflexed with undulate margins, 5–7 nerved, dorsal sepal 12–14 mm long, 8–11 mm wide, obovate to suborbicular, concave in the upper half, abaxial surface papillose, apex obtuse and minutely apiculate; lateral sepals 11–14 mm long, 7–9 mm wide, similar to the dorsal but partially fused at the very base, then free; petals 10–12 mm long, 9– 8 mm wide, ovoid to elliptical, somewhat oblique in natural position; labellum 3-lobed, 15–16 mm long from the base to the apex of the central lobe, 11–12 mm wide across the apices of the lateral lobes, the lateral lobes in the same plane as the central lobe and ± perpendicular to it; central lobe 6–8 mm long, 14–15 mm wide, transversely subquadrate, slightly emarginated, basally produced into a short isthmus that is 0.5–1 mm long and 5–6 mm wide; lateral lobes 3.5–4.0 mm long, 4–6 mm wide, erect-patent, subtriangular to semiovate with entire margins, somewhat inflexed in natural position; the callus consisting proximally of two lateral, divergent, upwardly dentate (3-teethed) keel, and distally of two lateral, upward, divergent teeth that are conical; the laterally compressed central keel runs parallel to the distal teeth and is bi or tri-dentate; column 4–5 mm long, 1.5–2.0 mm wide, oblong, the ventral surface in the same plane as the labellum lobes, tabula infrastigmatica longitudinally channeled, stigmatic cavity obovate, lilac pink; column wings divergent, 3.0– 3.5 mm long, 2.0–3.0 mm wide, lobes unequal in size, superior lobe shorter and narrower than the inferior, white with pale pink spots; anther cap 2–3 mm long, 1.8–2.0 mm wide, ellipsoid; pollinarium 1.8–2.0 mm long, 0.9 mm wide, composed of two obovate-elliptic pollinia, laminar stipe and a short, roughly hippocrepiform viscidium; capsule not seen.

Etymology:―This new species honors Gaspar Silvera and his daughter Katia who collected the plants and provided us with material, iconography, and ecological data. Gaspar is a well-known orchid nurseryman from Panama who has reproduced and raised many orchid species, including this one, from seeds. Katia is a specialist in the evolution of physiological mechanisms in epiphytes, particularly of CAM in orchids. The specific epithet was constructed in accordance to article 60C.1 ( McNeill et al. 2012), which specifies that when honoring more that one person in an epithet whose name ends in "a", the correct plural form should be constructed with the addition of - rum; thus "silvera-rum", after the Silveras.

Distribution and ecology:― Lophiaris silverarum is currently only known from two localities in central Panama, 115 km apart from each other, one in the Veraguas Province (the type collection) and another in the Coclé Province ( Figs. 2 View FIGURE 2 , 3 View FIGURE 3 ). We have not seen material from the second locality. The collectors of the species state that the type locality is at ca. 200 m and albeit they refer to it as Tropical Dry Forest ("Bosque seco tropical"), local precipitation approaches 2000 mm. The area topography is predominantly flat with few low-elevation hills in the vicinity. Also, according to the collectors, natural vegetation is very disturbed and seasonally burned with little forest coverage; soils are poor in nutrients. The plants were collected at the margins of the Subí River, where several orchid species are common on old remnant trees. These include Aspasia epidendroides Lindley (1832: 139) , Lockhartia amoena Endrés & Reichenbach (1872: 666) , Camaridium ochroleucum Lindley (1824 : t. 844), Cohniella helicantha ( Kränzlin 1922: 281) Cetzal & Carnevali (2010: 210) , Oncidium isthmii Schlechter (1922: 84) , Epidendrum coronatum Ruíz & Pavón (1798: 242) , and Sobralia decora Bateman (1841 : t. 26). Plants of Lophiaris silverarum are fairly frequent yet widely scattered in the area, where they commonly occur on a species of legume.

The second locality, Cabuya in Coclé Province, is at an elevation of approximately 400 m, where Lophiaris silverarum also grows on large trees in shady spots at margins of local streams and rivers. The topography of this area is predominantly hilly with most of the original vegetation also gone. Here, precipitation approaches 2500 mm and the vegetation is described by the collectors as dry-subtropical ("… seca subtropical …"). The collectors reported the species as locally rare and mention that it was absent from collections of orchid aficionados in the area.

The collectors of the species mention that according to their experience, there are phenological attributes that help separate Lophiaris silverarum from partially sympatric L. crispiflora . Whereas L. silverarum flowers locally in November-December, L. crispiflora blooms in April–May. After pollination, capsules of L. silverarum take eleven months to dehisce whereas in L. crispiflora they do so after six months. The evidence gathered by the collectors also indicate that, at least regionally, L. silverarum grows at slightly higher elevations (200–400 m) as opposed to the lowland, mostly coastal areas where L. crispiflora usually grows. Whether L. silverarum is actually sympatric with L. crispiflora is currently unknown at this time and more evidence is required to address this question.

Diagnostic features:― Lophiaris silverarum is similar to several other species of Lophiaris , particularly L. carthagenensis and L. crispiflora ( Fig. 4 View FIGURE 4 , Table 1 View TABLE 1 ), the first for Colombia and Venezuela, the second from Honduras through Panama. However, it is easily distinguished from these two species by the larger flowers (25–30 mm diameter across the spread dorsal sepal and labellar apex vs. 16–23 mm in both L. carthagenensis and L. crispiflora ). The color of the flowers is also strikingly different. In L. silverarum the background color of the flowers is pale straw-yellow with many, minute (<1mm diameter) non-confluent, laxly arranged pale reddishbrown spots. On the other hand, in the two aforementioned allied species (and other taxa related to L. oerstedii ), the base color of the tepals may be either straw-color or pale pink to pale purple, but the spots are much larger (> 1.5 mm) and always confluent. Furthermore, the isthmus of the labellum is wider (5 mm) in L. silverarum than it is in L. carthagenensis and L. crispiflora (2.5–4 mm). The calli of these three species are also different between each other, as indicated in the key provided herein and in Figure 4 View FIGURE 4 and Table 1 View TABLE 1 .

IUCN conservation category:―EN. We have no population data on this species beyond anecdotal comments by the collectors. Thus, we have relied upon the set of B criteria of the IUCN (2010). However, in view of the fact that the revision of hundreds of Lophiaris exsiccatae and other information from Panama, Costa Rica, and northwestern South America has yielded no additional records of the new species, we have to assume that it is either rare or only locally common. It is not impossible that Lophiaris silverarum may have been more common in the past before rampant anthropogenic disturbing of its habitats happened, but the species is nowadays likely confined to isolated large trees in pastures or along rivers. The new species is known from an area of approximately 2500 km 2, which is severely fragmented and likely to become even more so in the foreseeable future. Since L. silverarum is currently known from only two localities, the species meets criteria B1ab of the IUCN (2010) and should be considered as Endangered (EN).