Phytotaxa

Spiranthes minamitaniana (Orchidaceae), a new orchid species from Japan based on morphological and phylogenetic data

KENJI SUETSUGU — 2023-06-07

The delimitation of species within the genus Spiranthes (Orchidaceae) is problematic due to the intricate interplay of phenotypic plasticity, ecological variation, and hybridization, making identification that relies solely on morphology inadequate. In light of morphological and phylogenetic data, we have described a self-pollinating species, S. minamitaniana within the Spiranthes sinensis species complex. Spiranthes minamitaniana shares several morphological features with S. hachijoensis, such as glabrous inflorescence rachis, ovaries, and sepals, a degenerated rostellum, pollinia without a viscidium, and papillate lip basal callosities. However, it can be distinguished by several morphological traits, including semicircular, weakly- or non-3-lobed stigma, and more conspicuous anther cap. Although S. minamitaniana is morphologically most similar to S. hachijoensis, phylogenetic analysis strongly suggested that S. minamitaniana has independently acquired a selfing reproductive mode and constitutes a separate genetic cluster from it. As such, this taxon is morphologically and phylogenetically distinct from other closely related species. Consequently, this taxon is morphologically and phylogenetically distinct from other closely related species.

Pleurothallis pugio (Orchidaceae), a new Pleurothallidinae from Costa Rica

ADAM P. KARREMANS — 2023-06-07

A new species of Pleurothallis is described from Ciudad Quesada in Costa Rica. The novelty belongs to Pleurothallis series Acroniae Luer, having a close floral affinity with P. dentipetala and P. rowleei, from which it can be easily distinguished by the two-flowered inflorescence branches, bearing tiny yellow flowers with ovate-lanceolate, undulate dorsal sepal, decurved, oblong-lanceolate, dagger-like petals, and an ovate lip. Pleurothallis pugio is reminiscent of P. imitor, a species which also has two-flowered branches bearing yellow flowers. However, the latter is only known to occur in Monteverde Reserve at higher elevations, and differs in the petals that are only slightly decurved, with an entire margin, the sepals that are elliptic, and the lip that is triangular-sagittate.

**Novelties in Macrolobium (Detarioideae, Fabaceae) for Northern South America: Two new species and new chorological records from Colombia and Ecuador**

ANA MARÍA TRUJILLO-LÓPEZ — 2023-06-07

Two new species from Colombia are described and illustrated, Macrolobium ceriferum from the Pacific biogeographical region and Macrolobium longistipitatum from limits between Andes and Magdalena Valley biogeographical regions. Notes about their distribution, phenology, conservation status and taxonomic affinities are provided. Macrolobium ceriferum differs from morphologically similar species mainly by its leaflet blades discolorous and bullate, whitish abaxially, its smaller inflorescence axis and flowers, its filaments glabrous and presence of conspicuous scaly wax in the surface of the inflorescence axis, pedicel, bracteoles and sepals. Macrolobium longistipitatum differs from morphologically similar species mainly by its leaves with numerous leaflets, each with veins raised up the fourth-order on both surfaces, longer (sub-) terminal inflorescences, hypanthium cupular with longer stipe, sepals 4, slightly unequal in shape and size and ovary glabrous. The latter is the first record of Macrolobium sect. Macrolobium from the Inter-Andean Valleys of the northern Andes. Additionally, based in new chorological records of Macrolobium machaerioides from Colombia and Ecuador, its currently known geographical distribution are presented, along to an emended description of its fruits morphology, which is hitherto unknown.

**Two new species of Timonius (Rubiaceae: Guettardeae) from the Malay Peninsula**

PUI KIAT HOO — 2023-06-07

Two new species of Timonius endemic to the Malay Peninsula are described and illustrated: T. megalocalyx and T. denigricans, and their distribution and ecology discussed. Both species have been thought to be conspecific with their most resembling taxa in a previous revision but are here shown to be distinct.

Adiantum viscosum (Pteridaceae), a new species endemic to sclerophyllous forest of Central Chile

ARÓN CÁDIZ-VÉLIZ — 2023-06-07

Adiantum viscosum (Pteridaceae) is a new species of fern endemic to Central Chile that inhabits the sclerophyllous forest of the Valparaíso Region. Adiantum viscosum is morphologically similar to A. gertrudis and A. glanduliferum, but it differs by the presence of capitate and glandular trichomes throughout the aerial portion of the plant (pinnules, rachis, petioles and petiolules), which produce a sticky and aromatic resin. We provide a description of the species based on morphological analysis, insights about its ecology and habitat, distribution map, illustrations, a proposal for a conservation category according IUCN criteria, and a taxonomic key to the species of the genus Adiantum present in Chile.

**Typification of the North American species of Trillium subg. Trillium (Melanthiaceae: Parideae)**

AARON J. FLODEN — 2023-06-07

Here we provide type information and synonymy for the accepted North American species of Trillium subg. Trillium and notes on the distribution and character variation for some species. Lectotypes are designated for T. flexipes, T. rugelii and T. vaseyi. We also lectotypify the names T. cernuum var. declinatum f. billingtonii and T. cernuum var. declinatum f. walpolei, which have been associated with both T. cernuum and T. flexipes; T. cernuum f. tangerae; and T. rhomboideum var. album (=T. rugelii), which has often been associated with T. erectum.

Heisteria austroecuadorica (Erythropalaceae): A new species from southeastern Ecuador

XAVIER CORNEJO — 2023-06-07

Heisteria austroecuadorica, a new species of Erythropalaceae from the conserved evergreen montane forest at the San Francisco reserve, in southeastern Ecuador, is here described and illustrated. It is characterized by the flowers with 10 stamens, and relatively large fruits, with the apex conspicuously depressed, and the calyx not covering the base of the fruits. Heisteria austroecuadorica is assessed provisionally as Endangered.