Plant Geography Botany 422 2015 GREENHOUSE TOUR No. 1 The greenhouse is open weekdays from 8:00am to 4:00pm, and is located on the B2 basement level of Birge Hall. The greenhouses are numbered 1 to 8. (See the map on the last page of this handout). Please leave your bags and coats in the hallway so as to avoid knocking plants off tables. To find these plants, look for the number labels with orange tape! Greenhouse 2 (Tropical House) 1. Vachellia cornigera (Acacia cornigera) — bull-horn acacia (Fabaceae) • 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. Ficus nekbudu — big-leaved fig, West African rubbertree (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, this plant can start as an epiphyte and slowly envelope its support. All 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. 3. Monstera deliciosa — Swiss cheese plant, monstera (Araceae) • This genus (from the Neotropics) and its 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. 4. 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 the southeastern United States, from 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 prickles (“holly”-leaves) can be found in the Mediterranean biome as adaptations to marked seasonality in moisture availability. Greenhouse 3 (Orchid House) 5. Combretum sp. — orange flame vine (Combretaceae) • This species represents one of about 250 species in the largely tree 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, oftentimes overtaking the host tree; hence, lianas can be referred to as structural parasites. Notice the pliable nature of the branches. 6. Myrmecodia sp. — ant plant (Rubiaceae) • A genus of epiphytic myrmecophytes native to Southeast Asia and Australia. They form a symbiotic relationship with ants. Ant plants provide habitats for ant colonies high up in the forest canopy, protecting them from the elements and predators. Ants likewise provide defense for the plant, prevent tissue damage, and also provide nutrients to the plants by leaving wastes within tunnels inside the caudex. Special glands lining the tunnels then absorb nutrients for the plant. Greenhouse 4 (Tropical House w/pond) 7. Brugmansia suaveolens — angel’s trumpet (Solanaceae) • The tomato family is a dominant family of small trees, shrubs, herbs, and vines across the tropics. This small shrub from Brazail has large bat- (or moth) pollinated flowers. What adaptations to bat pollination do you see? All parts of the plant are quite poisonous, although it has been used ethnobotanically for centuries. 8. Rhizophora mangle — red mangrove (Rhizophoraceae) • The dominant mangrove in the Neotropics, especially prevalent close to the sea. Some adaptations to the halophytic lifestyle are evident: tough, evergreen leaves and prop roots. Pneumatophores are not evident on these young plants — why not perhaps? 9. 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 at 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. Greenhouse 5 (Begonia House) 10. Heliconia aurantiaca — 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. 11. Tillandsia — tillandsia, Spanish moss (Bromeliaceae) [in the “cloud forest” box] • The morphologically most unspecialized ("primitive", in a sense) members of this strictly Neotropical family are terrestrial xerophytes (Puya, Pitcairnia and Ananas, the pineapple). Intermediate in morphology are the tank epiphytes that use overlapping leaf bases to catch and store water (Vriesia, Neoregelia). The most specialized are the extremely modified epiphytic Tillandsia species, which are covered with absorptive scales to trap water in the canopy and lack root systems, at least as adults. Spanish moss, seen in the Tropical House and the Tropical High House, is a species very reduced relative to these species. Greenhouse 7 (Succulent House) 12. Pachypodium lamerei — Madagascar palm (Apocynaceae) • This bizarre “bottle tree” (here a small one) 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. 13. Fouquieria spp. — boojum tree, ocotillo (Fouquieriaceae) • This family only contains 12 species and is limited to the deserts of southwestern North America. Like many xerophytic shrubs, they are well-defended and loose their leaves during the dry season. In addition, once the rain comes these species flower profusely before producing a new flush of leaves. 14. Euphorbia spp. — spurges, poinsettia (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. Opuntia spp. — prickly pear cactus (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, such as this species, are epiphytes with flattened stems. To cope with life in such arid and sunny environments, cacti have evolved CAM (Crassulacean acid metabolism) photosynthesis, which allows them to reduce water loss during the day. CAM photosynthesis has evolved multiple times in plants including in Bromeliads (see Tillandsia above). There are two species of cacti native to Wisconsin! The epiphytic African Rhipsalis can be seen by the windows. *Be sure to examine the demo of Cactaceae, Euphorbiaceae, Asteraceae and Apocynaceae. Greenhouse 8 (High House) 16. 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. 17. Cyathea — tree fern (Cyatheaceae) • Cyathea is found in all tropical areas of the world and, like other tree ferns, often forms a conspicuous component of tropical rainforests. Tree ferns may grow up to 10 m tall but their trunks are not made up of wood. All new growth is supported by old leaf bases. Note the conspicuous way in which the new leaf “fiddlehead” emerges, characteristic of most ferns. This is called circinate vernation. 18. Adansonia madagascariensis — Madagascar baobab (Malvaceae) • A genus of nine species, most endemic to Madagascar but two in Africa and one in Australia. This species occurs in dry subtropical forests of Madagascar. This plant is deciduous; notice the palmately compound leaves (typical of the family) just starting to leaf out as the dry season is ending. All species are “bottle” trees, an adaptation to seasonal dry subtropical forests. 19. Carica papaya — papaya (Caricaceae) • The berry is like a pear-shaped cantaloupe melon and is a common fruit throughout the tropics and subtropics, although the species is native to the Americas. As with many other families, Caricaceae shares a South American-African distribution. Papaya produces mustard oils and molecular data relate it to the other mustard oil containing families, especially to the Moringaceae, which contains the horse-radish tree. 20. Theobroma cacao — cocoa tree (Malvaceae) • This species is native to tropical forests of the Americas. As with some non-canopy rainforest trees, the flowers are cauliflorous. The seeds of cocoa are used to make chocolate and are found in the large orange fruits (which monkeys love to eat).