Ilex paraguariensis is a dioecious (meaning it has separate male and female plants), evergreen tree that can reach up to 18m high.
The bark of the trunk is:
The simple, alternate leaves:
The petioles are dark-red, and about 1.27 cm in length.
The flowers are unisexual by abortion (so the plant is functionally dioecious) and both female and male flowers form corymbose inflorescences (small clusters) in the axils of the leaves. Flowers are tiny with 4 valvate sepals, each 1mm by 1mm, joined right at the base, and 4 whitish petals, each about 3mm by 2mm and also joined at the base.
There are 4 stamens in male flowers but these are reduced to sterile staminodes in the female flowers.
The fruits are: