Alfaroa williamsii is a tropical monoecious cloud forest

Cloud forest

A cloud forest, also called a fog forest, is a generally tropical or subtropical evergreen montane moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests often exhibit an abundance of mosses covering the ground and...

 dwelling species of tree first recognized in the Cordillera Central of Nicaragua

Nicaragua

Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...

 at an altitude of 1.3 km. The mature tree is 15-25 m in height, with a 0.5 m DBH

Diameter at breast height

Diameter at breast height, or DBH, is a standard method of expressing the diameter of the trunk or bole of a standing tree. DBH is one of the most common dendrometric measurements....

. The sub-opposite to alternate pinnately

Pinnate

Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...

 compound leaves bear three to five opposite to sub-opposite pairs of coriaceous leaflets, glabrous above and covered with minute scales below. The pollen is born on panicles consisting of several erect catkins. The small, nearly round, glabrous, ribbed fruits are born on a sparsely flowered spike.

The sub-species A. williamsii subsp. tapantiensis has been recognized by D. Stone.