Platanthera Rich. is a genus of ca. 125 species with a predominantly Northern Hemisphere distribution. A recent monograph of the genus did not cite important material from New Guinea. On the island the genus is represented by species from the tropical section Mecosa (Blume) Kraenzl. of subgenus Platanthera, which are not widely represented in herbaria and each specimen has a high value for taxonomic research. Studied materials not cited in the revision of the genus are cited as additional examined specimens here. A list of species with taxonomic and nomenclatural decisions is provided as a summary of knowledge about the genus on the island. Five taxa of Platanthera are recorded in this work for the region of New Guinea. One new taxon, Platanthera valkenburgii S.Nowak, Efimov, Szlach. & Kolan., is described. illustrated, and a photograph of the holotype is provided. The new species is readily distinguished by its strongly thickened to keel-like mid vein of the floral bract and dorsal sepal, petals at least as wide or wider than they are long, and its distinctly dilated lip. A key to the New Guinea taxa is provided. Two lectotypes are designated and taxonomic problems within Platanthera klossii (Ridl.) Efimov are discussed; one new combination is made.

Platanthera丰富。是ca的一个属。125种，主要分布在北半球。该属的最新专着并未引用新几内亚的重要材料。在岛上，该属以热带地区Mecosa（Blume）Kraenzl的物种为代表。Platanthera亚属，在草科中未广泛代表，每个标本对分类学研究都具有很高的价值。此处未引用属修订版中的研究材料作为附加检验样本。提供了具有分类学和命名学决定的物种列表，作为对该岛上属知识的总结。在这项工作中，新几内亚地区记录了五种Platanthera的分类单元。一个新的分类单元Platanthera valkenburgii S.Nowak，埃菲莫夫，斯拉赫。＆Kolan。，进行了描述。图示，并提供了完整的照片。新物种的特征是其花strongly片和背萼片强烈增厚到龙骨状中脉，花瓣至少长于其宽度或宽度，并且其唇明显扩张。提供了新几内亚分类群的密钥。指定了两种选型，并讨论了Platanthera klossii（Ridl。）Efimov中的分类学问题；一种新的组合。