The evergreen tree Michelia lacei W.W. Smith (with the synonyms M. uniflora, M. tignifera, M. magnifica and M. pachycarpa), of the family Magnoliaceae, occurs in Myanmar, Vietnam and China. In 2004 it was evaluated as occurring in fewer than five localities in China, with an estimated 50–60 mature individuals. This evaluation was based on the field knowledge of experts rather than on verification of occurrence in particular localities. The species was subsequently categorized as Critically Endangered on the China Species Red List in 2004 and on the Red List of Magnoliaceae published by Fauna & Flora International in 2007, and as Endangered on The Red List of Magnoliaceae revised and extended by Botanic Gardens Conservation International in 2016, and the IUCN Red List of Threatened Species in 2016. In March 2010 the species was identified as one of 62 plant species with extremely small populations in China.

To secure more reliable data on M. lacei in China a total of eight field surveys were carried out in south-east Yunnan during 2014–2016 with the joint support of the second survey of key protected wild plants in Wenshan and Honghe Prefectures (grant 39Y33G831261) and Yunnan Provincial Wildlife Conservation Projects (grant 201606). Field surveys in Wenshan Prefecture were conducted in May, July and December 2014 and November 2015 by Dao Zhiling, and in Honghe Prefecture in October 2014, August 2015, and June and September 2016 by Cai Lei. In total only three localities and 10 mature individuals have so far been recorded, in Maguan County (six individuals), Malipo County (three individuals) and Jinping County (one individual). There have been no known in situ conservation actions for this species until now, although the species is cultivated in five ex situ collections in botanical gardens in China. Our survey and information obtained in interviews with local people indicate that the main threats to this species are habitat degradation, forest loss and low production of fruits. At Kunming Botanical Garden, Yunnan, we planted several individuals of M. lacei, germinated from seed collected in Jinping County in 1987 but, with the exception of one individual that flowered in 2009, they have not flowered or fruited.

Urgent measures need to be taken to protect this rare species of Magnoliaceae, and therefore Kunming Botanical Garden is now going to establish in situ conservation for M. lacei and study its reproductive biology. To elucidate the species' conservation status fully, further surveys are required in south-western China, Myanmar and northern Vietnam, and also in other areas of its potential range, such as Laos.