The Huascaran National Park - International Biosphere Reserve is located in the Cordillera Blanca, the highest tropical mountain range in the world. The flora of this mountain range is of interest for biogeographic, conservation, and economic reasons;The work is divided into two parts. In the first part, the geology, climate, and vegetation of the Park are introduced, a list of the taxa included in the flora is presented, and the biogeographic relationships of the flora are reviewed. In the second part, there are taxomonic treatments of the species of monocots in the flora, except those of the Poaceae;The flora consists of 104 families, 339 genera, and 799 species of vascular plants. Of these, 8% of the species are Pteridophytes, 26% Monocots, and 66% Dicots. The Gymnosperms are represented by one species of Ephedra;The Huascaran flora is an equatorial temperate flora principally of American origin, many of the genera being strictly Andean. Given the continuity of the Andes, it is closely related to the floras of the paramos of the north and east, and to the puna to the south.