Mexico is one of the most diverse countries on earth. Most of tropical Mexico is seasonally dry, and the wildly rugged and varied topography has led to a fantastically colorful and striking biota. Click on a thumbnail for a larger image:
1. The bark of the Cuachalalà Tree (Amphipterygium
adstringens) in the family Julianiaceae is used for a variety
of medicinal purposses. The corky, thorn-like projections on the
tree trunk are made into small carvings. This tree was photographed
on the Puebla- Oaxaca border.
2. This Giant Barrel Cactus (Echinocactus platyacanthus) is about 2 meters tall! The range of this species straddles the Tropic of Cancer. More images of cacti are on the Cactus Page.
3. Epiphytes (plants that grow on other plants without parasitizing them) are not restricted to the rainforest. This tank bromeliad in the genus Tillandsia (Bromeliaceae) is growing on the trunk of a cactus, Cephalocereus tetetzo (Cactaceae) in southern Puebla. The Bromeliaceae and the Cactaceae are the two largest families that are restricted to the New World. To see more images of bromeliads from Mexican tropical dry habitats, see the Bromeliad Page.
4. This Clathrus fungus was growing on the forest floor in the northern Yucatàn Peninsula.
5. The genus Bursera (Burseraceae) reaches
its peak of diversity in the tropical dry forests of central
Mexico. The genus consists of about 100 species and ranges from
southern California to northwestern South America, but over 60
of these species are concentrated in the Balsas River basin of
central Mexico! They are often wonderfully aromatic and one section
of the genus is characterized by metallic, peeling bark.
6. The cactus in this picture from southern Puebla is Cephalocereus columna-trajani. Like the Column of Trajan in Rome, Cephalocereus columna-trajani is tall, white, and has no branches. It's surreal and almost eerie to see hillsides covered with these huge plants, each one with its tip pointed slightly southward like ranks of giant, ghostly people all looking in the same direction. The shrub with magenta flowers is Morkillia in the Zygophyllaceae.
7. Cycads are very old plants that were around during the time of the dinosaurs, long before flowering plants existed. Mexico has one of the highest concentrations of cycads of any country on earth. This cycad, Dioon edule, growing on sharp, fluted limestone was photographed close to the Tropic of Cancer in the state of Tamaulipas.
8. The weird bottle tree Fouquieria purpusii (Fouquieriaceae) is only found in few localities in central Mexican dry forest. It is a relative of the ocotillo of the southwestern US.
9. The orange structures covered with a checkerboard pattern
in this photo are the flowering and fruiting structures of an
underground parasite in the family Balanophoraceae. Most of the
year, the plant is entirely underground, where it gets all of
its nutrients by stealing them from the roots of other plants.
Balanophoraceae are usually only seen when they poke their flowers
10. Many plants in tropical dry forest flower during the dry season, such as this Ceiba parvifolia (Bombacaceae) in southern Puebla.
11. The trunk of Ceiba parvifolia (Bombacaceae) is covered with long, woody prickles.
12. The flowers of Pseudobombax (also Bombacaceae) appear when during the leafless dry season.
13. Bursera longipes is one of the many species of
Bursera that populate Mexican dry forest. The coppery
bark of this species is particularly striking. This one is from
14. Another odd inhabitant of Mexican dry forests is Ipomoea arborescens, a member of the Morning Glory Family (Convolvulaceae), and in the same genus as the sweet potato (Ipomoea batatas)! This individual was photographed in southern Puebla.
15. A flowering twig of Lycium, in the Tomato Family (Solanaceae).
16. and 17. The genus Cordia in the Boraginaceae has a center of diversity in Mexican dry forests. 16. shows a tree of Cordia eleagnoides and 17 (below) is Cordia curassavica, both from Guerrero.
18. Cacti are often associated with deserts, but cactus diversity
is actually highest within the tropics. Cactus densities are
also often very high, as can be seen in this dense thicket of
at least 4 species of cactus in southern Puebla. The tree in
the upper right corner is Cercidium praecox. The tufts
in its branches are a species of Tillandsia.
19. The cacti Astrophytum ornatum (upper cactus) and Mammillaria hahniana (lower cactus) are commonly cultivated as ornamentals. In the wild, they occur in a rich community with many other plants. In this photo taken on a steep limestone cliff, the cacti are growing with ferns, liverworts, and Commelinaceae. The green fronds on the middle right are the a club moss Selaginella.
20. The broad, dark green leaves of Wigandia urens (Hydrophyllaceae) are covered with tiny, stinging hairs. This one was photographed in Hidalgo.
21. At the upper elevational extent of tropical dry forests
in Mexico, there is often a transition to oak forest. At these
elevations, it is common to find associations like this one in
southwestern Puebla of oaks and palm trees growing together.
22. Still higher, in eastern Puebla, communities of Nolina, Dasylirion (Agavaceae), and piñon pine. The pine is draped with tresses of the epiphytic bromeliad Tillandsia usneoides.
23. The carnivorous Butterwort genus Pinguicula (Lentibulariaceae) has a center of diversity in Mexico. While usually thought of as growing in wet places, there are numerous species that are found in seasonally dry habitats.
Images from Mexico are also on the Beaucarnea Page, the Cactus Family Page, the Legume Family Page, and the Pineapple Family Page.