Authority: Buck, William R. 1987. Bryostephane Steereana: A Collection of Bryological Papers Presented to William Campbell Steere On The Occasion of His 80th Birthday. Mem. New York Bot. Gard. 45: 1-749.
The long, secondary branches (3-4 cm) with crispate leaves arranged in more or less spiral rows and the nearly sessile capsules are rather characteristic for this Macromitrium. Its more or less secund, lanceolate leaf with long acuminate apex distinguishes the species from most other Philippine Macromitria, except M . angustifolium Dozy & Molk. and M . cuspidatum Hampe. However, the latter two species differ in having only smooth basal leaf cells. From M. cuspidatum, the present species can be separated further by having only a percurrent to weakly excurrent leaf costa. A good illustration of M . longicaule is in Heischer (1900-1923).
It is surprising that this locally widespread species remained unrecognized for such a long period of time.