Greenhouse 2
1. Vachellia cornigera (Acacia cornigera) - bull-horn acacia (Mimosaceae)
A famous mutualism: the acacia provides food and shelter for ants, which in turn protect the plant from herbivores. The shelter is in the form of hollow, stipular thorns. The food is in the form of "Beltian bodies", little globs of oil and protein at the tips of leaflets (look closely). These are named for the "Naturalist of Nicaragua", Thomas Belt. Acacia s.l. has been shown to be polyphyletic and was subsequently split into five different genera. “Acacia” can still be used as a common name but as a genus name now only refers to a number of Australian species.
2. Monstera deliciosa - swiss cheese plant, monstera (Araceae)
This genus (from the Neotropics) and relatives are some of the dominant epiphytes or hemi-epiphytes in tropical forests. This species starts rooted in the ground and grows towards the dark (i.e., tree trunks); once attached it grows up to the light - hence it is a "roving" hemi epiphyte. The adaptive value of the fenestrations ("windows") is still debatable. Click to see a Monstera plant eating a car!
3. Osmanthus heterophyllus — holly olive (Oleaceae)
This genus in the olive family is mostly native to warm, wet temperate forests (subtropical humid) but with one species (O. americanus) in southeastern North America (southeastern United States, Texas to Virginia). This biome type is often characterized by tough, evergreen leaves adapted to year-round growing conditions but with marked seasonality in temperature. Similar leaves with sharp serrations (“holly”-leaves) can be found in the Mediterranean biome as adaptations to marked seasonality in moisture availability.
4. Combretum fruticosum – orange flame vine (Combretaceae)
This species represents the type specimen of both the genus Combretum (~250 spp.) and the family Combretaceae. Most Neotropical and Asian Combretum species have shifted to the liana habit and utilize this cost effective method for rapid growth into the canopy. Once in the canopy, the lianas branch profusely, often times overtaking the host tree; hence, lianas can be referred to as structural parasites. Notice the pliable nature of the branches.
Greenhouse 3 (Orchid House)
5. Seemania sylvatica — (Gesneriaceae)
This herb is a member of the “African violet family,” which is mostly found in the tropics. The family is characteristic of tropical rain forest understories, and its members often have fuzzy leaves that are oppositely arranged on the stem. (Note the many different plants in this family, arranged from here to the greenhouse door!) Flowers of the Neotropical species are usually funnel-shaped for pollination by hummingbirds — an almost strictly Neotropical group of birds.
6. Orchid species - orchid (Orchidaceae)
There are many representatives of this giant plant family (~25,000 spp.) on the surrounding tables and walls. The family is known for its intricate pollination mechanisms, beautiful flowers, and epiphytic habit. Many of these species are “planted” on cork board or in shredded bark to mimic the tree branches they would grow on in the wild. Notice the swollen leaf bases called pseudobulbs, these are an adaptation for the storage of water. Some species hanging from the ceiling have large roots that are capable of photosynthesis!
7. Welwitschia mirabilis (W. bainesii) - (Welwitschiaceae)
This weird gymnosperm is endemic to the Namib desert of southwestern Africa. Note the peculiar morphology: a caudex producing two leaves with basal meristems. These leaves later fray so as to appear more numerous. It has a taproot to 3 m deep but this just serves to anchor the plant and doesn't absorb or transport water. Since it virtually never rains where this plant grows, it has adapted as a nephelophyte, a plant that gets its water via fog absorbed by stomata on the upper leaf surface. [See also the display case on the 1st floor hallway near room 122.]
8. Myrmecodia sp. — antplant (Rubiaceae)
A genus of epiphytic myrmecophytes (ant plants) native to the Southeast Asian rainforests. They form a symbiotic relationship with ants. Ant plants provide habitats for ant colonies high up into the forest canopy, protecting them from the elements and also predators because of the spines. Ants likewise provide defense for the plant, prevent tissue damage, and also provide nutrients to the plants by leaving wastes within the tunnels inside the caudex. Special glands lining the tunnels then absorb nutrients for the plant.
Greenhouse 4 (Tropical House with pond)
9. Rhizophora mangle - red mangrove (Rhizophoraceae)
The dominant mangrove in the Neotropics, especially prevalent close to the sea. Several adaptations to the halophytic life style (what does that mean?) are evident: tough, evergreen leaves; prop roots. Pneumatophores are not evident on this young plant - why not perhaps?
10. Platycerium bifurcatum – Staghorn fern (Polypodiaceae)
This epiphytic fern grows in the Old World tropics. As the leaves of the plant die, they remain attached to the base of the plant. As the dead leaves accumulate, they form humus as the base of the plant, catching and storing water and nutrients – a “trash basket” into which roots can penetrate. These large “baskets” at the base of the plant are capable of holding gallons of water.
11. Blechnum gibbum — dwarf tree fern (Blechnaceae)
This tree fern genus is cosmopolitan in tropical regions of the southern hemisphere and is a close relative of the widespread genus Cyathea. Tree ferns are very characteristic of moist tropical mountains or cloud forests, with a few reaching into temperate rainforests only in the southern hemisphere.
Greenhouse 5 (Begonia House)
12. Heliconia aurantiacum — heliconia (Heliconiaceae)
This plant’s red “flowers” are actually colorful bracts; the tiny flowers are hidden within them. Like its relative the bird-of-paradise (Strelitzia), the bracts on this plant draw in avian pollinators with their vibrant colors. Different species of heliconia have different-shaped bracts, some of which hang upside down. This allows only certain hummingbirds to pollinate a particular species. One species in the old-world tropics is pollinated by bats.
Greenhouse 7 (Desert House)
13. Pachypodium laneri — Madagascar palm (Apocynaceae)
This bizarre “bottle tree” from Madagascar is not a true palm but is in the same family as dogbane and periwinkle. It is found in dry thorn forests. The stem enlarges as it grows, storing large quantities of water. All members of the family, including the milkweeds (formerly placed in Asclepiadaceae), have a well-developed latex system for protecting its costly parts from herbivores.
14. Euphorbia spp. — spurge (Euphorbiaceae)
This genus contains ca. 2,000 species and is cosmopolitan. There are many species from Africa and Madagascar (on display here) that resemble cacti. What xerophytic adaptations do they share? Although some spurges are extremely similar to cacti, it is very easy to differentiate the two, even when not in flower. Prick a spurge stem and then a cactus stem. What do you notice?
15. Cactus species — cacti (Cactaceae)
Cacti are a large family (2,000 spp.) almost entirely restricted to the New World. They are famous as a symbol of the American deserts. Most species have swollen, fluted stems that hold water during long periods of drought. Some species are giant columnar “trees”, some are multi-branched shrubs, others are globose stems, and still others are epiphytes with flattened stems. Some basal cacti (Pereskia) are also exhibited here: they look like “normal” plants with non-succulent leaves and stems. There are two species of cacti native to Wisconsin!
16. Didierea trollii — octopus tree (Didiereaceae)
A representative of a tiny family that is dominant in southwestern Madagascar. The family contains only 16 species in 7 genera. It looks similar to the American Cactaceae, although many thought this was simply convergence. Its mysterious relationships were illuminated with DNA sequences that showed that it is in fact somewhat related to cacti – perhaps indicating parallel rather than convergent evolution in growth form in two distinct areas of the world. This species grows several creeping stems before sprouting upright stems. This ends up creating a large mass of low-growing thorny branches protecting the center upright ones; perhaps a way of protecting against extinct herbivores (e.g. elephant bird).
17. Huernia schneideriana — a stapeliad (Apocynaceae)
The stapeliads are a group of succulent milkweeds found in Africa, Madagascar, and Arabia. They are an example of convergent evolution sharing many features with cacti and succulent euphorbias such as tiny leaves and ribbed stems. All species have foul-smelling flowers that are vibrantly colored, both features giving them a resemblance to rotting flesh. This attracts flies to affect pollination. Take a whiff of the small, maroon flower on this plant. Pleasant!
*Be sure to examine the demonstrations of Cactaceae, Euphorbiaceae, Asteraceae and Apocynaceae.
Greenhouse 8 - Tropical High House
18. Calliandra haematocephala — red powderpuff (Fabaceae)
A species-rich genus of the most important family of trees of tropical wet and dry forests – the legume family. Although some are trees, other members of the genus are more herbaceous. Compound leaves are common in the family and in tropical forests, in general. The striking colored large cluster of many, small flowers are adapted to bird pollination in all three tropical regions of the world – although the groups of birds in each are quite different.
19. Pachira quinata - shaving-brush tree (Malvaceae)
This tree is found in the subtropical deciduous forest of Central America. Note the presence of trunk thorns so characteristic of these dry forests. What purpose could they serve? The Malvaceae is a family typically exhibiting compound leaves. The common name is derived from the appearance of the flowers: like old-timey shaving brushes.
20. Ficus nekbudu - Kaffir fig (Moraceae)
A strangling fig native to tropical Africa. Like many species in this large genus (ca. 800 species) found in all three tropical floristic regions, the plant can start as an epiphyte and slowly envelope its support. The figs are pollinated by wasps and, as in the orchids, a particular species of wasp often has coevolved to pollinate a particular species of fig. Click here to see images of a strangler fig which has killed its host tree and now has a hollow center.
