单花无柱兰又名义花无柱兰。植株高6-10厘米。块茎小，卵球形或圆球形，长约5毫米，肉质。茎纤细，直立或近直立，基部具1-2枚筒状鞘，下部光滑，在近基部至中部具1枚叶，顶生1朵花。叶片披针形、倒披针状匙形或狭长圆形，长2-3厘米，宽6-10毫米，先端急尖或钝，基部收狭成抱茎的鞘。花苞片线状披针形，先端急尖，较子房长，但短于花；子房纺锤形，扭转，无毛，连花梗长6-11毫米；花中等大，淡紫色，粉红色或白色，具紫色斑点；萼片先端钝，具1脉，中萼片直立，凹陷呈舟状，狭卵形，长4毫米，下部宽1.6毫米；侧萼片狭长圆状椭圆形，长约5毫米，宽约1.6毫米；花瓣直立，斜卵形，与中萼片等长而较宽，并与中萼片相靠合，具1脉；唇瓣向前伸展，张开，内面被短柔毛，长、宽均约8毫米，近基部收狭成短爪，基部具距，中部之下3裂，侧裂片楔状长圆形，先端截形或钝，边缘全缘或微波状，中裂片倒卵形，较侧裂片宽多，先端凹缺呈2浅裂，边缘全缘或微波状；距圆筒状，下垂，长3-4毫米，末端钝，长为子房的1/3或1/2；蕊柱短，直立；花药近球形，直立，药室基部靠近，顶部叉开；花粉团近球形，具花粉团柄和粘盘，粘盘卵形；蕊喙小，三角形，直立；柱头2个，隆起，近四方形；退化雄蕊2个，小，圆形。花期7-8月。

        在通向黄龙的山梁雪山梁上， 就生长着单花无柱兰这种纤小的植物。它的花为白色，直径很小只有约7-8毫米大，唇瓣上具有红紫色斑点。而在岷山的其他地方，该种的花通常会稍大一些，花色为暗粉色或红紫色， 唇瓣上有暗红紫色斑点。单花无柱兰只有一片叶，地下具有小块茎，直径约为5毫米，植株顶部着生一朵花。该种通常生长在高山草甸和开阔灌木丛间的草地上， 海拔3100到3600 米。植株一般高5-10厘米，花直径为7-12毫米。

        Published in Feddes Repertitorium Specierum Novarum Regni Vegetabilis, Beihef te, Band 4, Orchideologiae Sino-Japonicae Prodomus: 94. 1919.

        Based on Peristylus monanthus Finet, Revue générale de Botanique 8: 523, 1901.

        A synonym is Amitostigma nivale Schlechter, Acta Hor ti Gothoburgensis 1: 132. 1924. The type was collected by Harry Smith in Huanglong 1922.

        On the Xueshanliang, the pass leading to Huanglong, the tiny species has so far only been seen with small white flowers of about 7-8 mm diameter and with magenta spots on the lip. In other places in the Minshan the flowers are usually a little bigger and often pale pink to magenta with dark magenta spots on the lip. The plant carries a single leaf, has small tuber of 5 mm diameter and is single flowered. It grows usually in alpine meadows and in grassy patches between open shrubs at altitudes from 3100 to 3600 m. The plant is 5-10 cm tall and the flower has a diameter of 7-12 mm.

        Flowering: June early July.