Liparis aphylla (Malaxideae, Orchidaceae), a new leafless record from Peru

Abstract Liparis aphylla G.A.Romero & Garay was previously known only from two herbarium specimens collected in 1945 and 1977 in Ecuador and Colombia, respectively. This little-known species is hereby reported for the first time for Peru. An updated description, line illustration, color photographs and distribution map of Liparis aphylla, as well as an identification key to the Peruvian species of Liparis are provided.


Introduction
Liparis Rich. s.l. is a large cosmopolitan genus of about 480 species, reported in tropical Asia, Malesia, eastern Australia, the Pacifi c Islands (including Hawaii and Tahiti), Madagascar, Africa, subtropical and tropical Americas, temperate Europe, Asia and North America. Th e genus is composed of both terrestrial and epiphytic species; with small to prominent pseudobulbs; one to several (rarely none) conduplicate to plicate leaves, a terminal infl orescence of one to many; fl owers usually resupinate, small or medium-sized, yellow, green, orange, or purple; the sepals are similar, although the lateral ones are often wider and shorter than the dorsal one; the labellum is fi rmly attached to a footless, often arched column; the incumbent anther bears four pollinia grouped in two pairs, and lacking caudicles or stipe but with minute viscidium. According to a recent molecular phylogenetic study (Cameron 2005), Liparis contains four major clades, two of which include primarily Asiatic-Malesian epiphytic taxa with narrow conduplicate leaves, and the other two consist mostly of terrestrial plants with worldwide distribution and broader, conduplicate to plicate leaves. However, further studies are needed to better understand its evolutionary history and to clarify its delimitation and position within the tribe Malaxideae. Schlechter (1921), compiled the fi rst account of Liparis in Peru and reported three species, namely L. crispifolia Rchb.f, L. elegantula Kraenzl, and L. ramosa Poepp. & Endl. Later, Schweinfurth (1959) Ormerod 2012). As far as we know, L. neuroglossa is only known from the Bolivian type collection. Taking into account the previous records and four additional Peruvian species described by Ormerod (2012), currently we recognize the following 11 species for this country: L. ecallosa Ormerod, L. elegantula, L. laticuneata, L. nervosa, L. ramosa, L. retusa, L. rusbyi Rolfe, L. schunkei Ormerod, L. serratiloba Ormerod, L. vargasii Ormerod, and L. vexillifera. During fi eld exploration conducted by the senior author in the montane rainforest of Cajamarca, Peru, in 2014, a small terrestrial individual plant of Liparis was collected and subsequently identifi ed as Liparis aphylla. Because of the scarcity of information about this rare orchid, we provide an updated description and line illustration, we illustrate it with color photos for the fi rst time and we provide additional information regarding its ecology and morphological variation.

Materials and methods
A live plant of Liparis aphylla was collected in May 2014 in Cajamarca, Peru (see detailed locality data under "Additional specimen examined" below). Specimen identifi cation was made by comparing the plant with the original publication of the species in Garay and Romero (1999). A herbarium specimen was prepared, and two fl owers were preserved in a solution consisting of 70% ethanol, 20% water, and 10% glycerol. An updated description was prepared based on all collections of L. aphylla available (either physical specimens or digital images). Type. COLOMBIA. Boyacá: Sierra del Cocuy, 2800 m, "terrestre, entre musgos asociada con Masdevallia sp., aparentemente saprófi ta; tépalos blanco-verdosos, labelo púrpura lila" 20 July 1997, M. Ospina Hernández 1487 (Holotype: AMES!).
Ecology and distribution. Liparis aphylla is found in the Andes of Colombia, Ecuador and Peru, within an elevation range of 2600-3300 m. Th e distribution of this species, based on herbarium records, appears to be highly disjunct (Figure 3). However, this extreme patchiness may be an artifact of limited collecting, and we suspect that L. aphylla likely occurs throughout the Andean range, at climatically suitable locations ranging from the Cordillera Oriental/East Andes in Colombia to the northern Andes of Peru. Plants of L. aphylla grow terrestrially among loose moss in wet, cold montane cloud forest with abundant bryophytes. Flowering period: May-July.  (AMES!, NY); PERU. Departamento Cajamarca, provincia Chota, Querocoto, entrance road to "La Granja", 6°20'6.70"S, 79°9'24.49"W; terrestrial, montane rainforest, 2600 m, 01 May 2014, A. Damian 0100 (MOL!, ADP-spirit 3033).
Conservation status. Th is species is presently know only from three location worldwide; according to the IUCN Red List (IUCN 2014) and Roque and Leon (2006) criteria, it should be listed as critically endangered (CR) B1ab(iii).
Discussion. Liparis aphylla was described from an individual plant collected in Sierra del Cocuy, Colombia, by Romero and Garay (1997) and from another record from Azuay, Ecuador, (1977). Th ese two specimens, along with the Peruvian specimen reported in this paper, represent the only available material of this tiny rare orchid. Th e overall morphology observed in these three specimens, is quite uniform except for considerable variation in labellum shape, which ranges from quadrate in the specimen Camp E-4774 to subquadrate in Ospina Hernández 1487. Moreover, the elliptic concavity of the callus of our specimen did not appear to be present in other two specimens, although it is not clear if the absence of this concavity in the latter two specimens is an artifact of preservation.
Unlike any others members of Liparis, L. aphylla appears as a leafl ess orchid with poor-developed root system. However, these two conditions need to be studied care-fully. Although we were unable to see any remnant roots or rhizome on the specimens examined, Ospina Hernandez sheet (1487) includes an interesting note cited as "Plant tubers covered by fungal hyphae (...)". It is highly possible that "tubers" on this context actually refers to the pseudobulb and not to the presence of subterranean stems or shoots that resemble any kind of root-like system or rhizome as it occurs in many basal Epidendroids orchids (Pridgeon et al. 2005, Campbell 2014. A closest analysis of the original drawing of L. aphylla by Romero and Garay (1997) shows sort of fi lamentous structures emerging beneath the pseudobulb. Since the dimensions of these formations are indistinct (0.3 × 0.1 cm), is fairly accurate to attribute those fi lamentouse root-like structures to the "fungal hyphae" which Ospina was referring in the fi rst place.
Another strikingly feature on L. aphylla is its leafl essness. As it happens with rhizome and roots, no remnants of withered or decomposed leaves were observed neither in the fi eld nor in available herbarium specimens. As a result of this uncommon state within Liparis, Romero & Garay decided to establish Sect. Aphylla (Romero and Garay 1997) to include this single species, which outstands essentially for its leafl ess habit, well-developed pseudobulb, plants of small size and muscicolous habitat. However, additional observations whether this set of characters, especially those referring to leaves and roots, are continuous or not along specimens were missing.
Leafl essness is a feature that is present in many angiosperms (Vicent et al. 2013, Calswards et al. 2006) and Orchidaceae is not the exception. At least 235 orchid species and 43 genera are leafl ess, most of them found in Epidendroideae (Freudenstein  (Vincent et al. 2013). Most of these leafless orchid display any of the following arrangements or life-forms: (1) well-developed shoot system which forms the main body (e.g. leafl ess Vanilla), (2) shoot system reduced, i.e. shootless orchids, roots forming the main body of the plant (e.g. Vandeae) (Carlsward et al. 2006), (3) roots fl eshy, fasciculate, leaves basal but lacking at fl owering time (e.g. Spiranthinae: Cranichideae) (Salazar 2003), and (4) myco-heterotrophic orchids, achlorophyllous, roots reduced or absent, rhizome fl eshy, coralloid, tuberlike or cylindric (e.g. Aphyllorchis, Gastrodia) (Rasmussen 2000). A major question rise then among others, which life-form represents better to L. aphylla?. Although Romero and Garay (1997) suggested it could be referred to as a "saprophyte", this term proved to be inaccurate (Leake 1994). We believed L. aphylla could represent a partially mycoheterotrophic (holo-mycotrophic) plant, i.e. clorophyllous plant that combines autotrophy and myco-heterotrophy to obtain carbon during at least one stage of its life cycle (Rasmussen 1995). Th e nonexistence of a well-developed root system, leafl essness (= myco-heterotrophic species) and retainment of chlorophyll on its basal sheath, stem and bracts seem to confi rm this hypothesis. Nonetheless, it is important to keep in mind that the myco-heterotrophic status is "putative" on this species, and remains speculative until a careful physiological analysis has been carried out.