LOWLAND TROPICS

In the steamy, lush jungles of the Lowland Tropics Gallery, a light rain falls on the canopy of majestic palms. An enormous kapok tree lies on the forest floor while brightly colored orchids and falling water cascade around it. Coffee berries, cacao pods, and tropical fruits hang heavily from branches, and the sweet fragrance of jasmine and Stanhopea orchids mingle in the air. The gallery is also home to the Conservatory’s centenarians, including the towering Imperial Philodendron, a pygmy date palm from San Francisco’s 1915 Panama-Pacific International Exhibition, and 100-year old Cycads, which are primitive gymnosperms that pre-date the dinosaurs.

You can visit all the galleries: Potted Plants | Lowland Tropics | Highland Tropics | Aquatic Plants

Click images to enlarge.

Acalypha hispida
Common Name: Chenille plant
Family Name: Euphorbiaceae
Native to: New Guinea and the Malay Archipelago

The common name, chenille, means caterpillar in French. The fuzzy, pendulous inflorescence of the chenille plant range in color from vibrant red through a creamy white. The chenille plant is dioecious, meaning the male (staminate) and female (pistillate) flowers are on separate plants. The individual flowers which make up the inflorescence are very tiny, have no petals, and are made up of feathery pistils. These pistils are tightly packed into cylindrical flower clusters along the raceme called catkins. Flowers with catkins, including the chenille, are predominantly pollinated by wind, and occasionally by insects.

Areca vestiaria
Common Name: Orange Crownshaft Palm
Family Name: Arecaceae
Native to: Eastern Indonesia, Maluku, and Sulawesi

This palm varies from a red crown shaft with maroon leaves, to an orange version with green leaves, and everything in between. It has been observed that there is substantial color variation depending on elevation, with the more colorful plants coming from higher elevations. This photo shows the three stages of the palm’s fruit – the yellow inflorescence emerging, the full-sized but unripe yellow fruit, and the ripe red fruit.

Brownea coccinea
Common Name: Scarlet Flame Bean
Family Name: Fabaceae
Native to: Guyana, Venezuela, Brazil, Trinidad and Tobago

Spectacular heads of red flowers are 4 to 6 inches in diameter and only last a few days. New leaves emerge in pale pinkish brown hanging clusters.The presence of the red pigment anthocyanin may be to protect the developing chlorophyll inside the new leaves from too much ultraviolet light. There are also theories that brown leaves give the appearance that the leaves are dead, making them unappetizing to predators.

Carica papaya
Common Name: Papaya
Family Name: Caricaceae
Native to: Tropical America 

The papaya is commonly referred to as a “tree,” but it is technically a giant herb because it never produces true woody tissue.

The papaya typically has a single, unbranched, non-woody trunk. The trunk is topped by an umbrella-like canopy of palmately lobed leaves. The stems and leaves contain white milky latex. Papayas are dioecious (male and female flowers are on separate plants), but many cultivars are hermaphroditic. Their yellowish-white trumpet-shaped flowers are fragrant and bloom throughout the year.

The papaya is used all over the world in traditional medicine for its digestive, wound-healing, and anthelmintic (drugs that expel parasitic worms) properties. These properties originate from the presence of the enzyme papain in the latex of the papaya plant and its fruit.

Clerodendrum quadriloculare
Common Name: Starburst, Shooting Star
Family Name: Lamiaceae
Native to: Philippines and New Guinea

Clerodendrum are leafy vines or shrubs, bloom in the winter, and are used as ornamentals. The Conservatory’s plant is easy to spot because of the dramatic clusters of long white flowers. The genus Clerodendrum gets is name as a derivation of Greek words, kleros meaning “by chance”, and dendron, meaning “tree”. This is a reference to the reports of medicinal usefulness throughout eastern medicinal literature (including from India to Thailand to Japan) referring to extracts from the roots and leaves of Clerodendrum in the treatment of diabetes, obesity, asthma, syphilis, cataracts and malaria, among other conditions.

Coffea arabica
Common Name: Coffee
Family Name: Rubiaceae
Native to: Ethiopia

Coffea arabica and Coffea canephora are the two major commercially grown species of coffee. Arabica is said to produce better tasting coffee because the lower caffeine content makes it less bitter.

Scientists have determined a number of ways coffee plants use caffeine to their benefit. When leaves die and decompose on the ground they contaminate the soil with caffeine which makes it difficult for other plants to grow. Coffee plants also use caffeine to deter insects from eating their leaves and beans. At the high doses of caffeine contained in these plant parts, a bite can be fatal to insects. But the nectar contained in coffee flowers is laced with a small dose of caffeine. When insects feed on caffeine-spiked nectar, they are more likely to remember the flower and revisit it again, which aids in pollen dispersal.

Crescentia cujete
Common Name: Calabash Tree
Family Name: Bignoniaceae
Native to: Central and South America

Dried calabash fruit are used to make instruments and small vessels for serving or drinking.  Crescetia cujete shares its common name with that of the vine calabash (Lagenaria siceraria). Calabash trees are cauliflorous. Cauliflory is a botanical term referring to plants which flower and fruit from their main stems or woody trunks. This can allow trees to be pollinated or have their seeds dispersed by animals which cannot climb or fly. The trunks and larger stems also allow more support for heavy fruit. Other examples of cauliflorous plants in the Conservatory are cacao and papaya.

Dioon spinulosum
Common Name: Giant Dioon
Family Name: Zamiaceae
Native to: Veracruz and Oaxaca, Mexico

Cycads are usually linked to palms or ferns, when in fact they are not related to either. They are actually a unique, ancient family unrelated to any other group of living plants. Cycads flourished in the Mesozoic Era some 250 million years ago. This specimen is over 100 years old.

Dioon spinulosum is one of the tallest cycad species in the world, growing to 40 feet high.  A cycad is either male or female and the cones of each sex are usually quite different in size and shape.  The two cones on this female plant are emerging from the center of the leaf tufts at the top of the plant and will soon be as large as in the photo. They will grow upwards and then grow down. When the cones ripen and open they will reveal hundreds of orange, unfertilized ovules. For the cone’s ovules to be fertilized, the Conservatory would need pollen from a male plant of the same species, which we do not have at the Conservatory. So, this giant Dioon will repeat it’s cycle of producing unfertilized cones, year after year, without producing offspring. Fortunately, cycads can also produce stem offshoots or suckers (often called pups). These can be separated from the parent and rooted to create new plants.

Hibiscus schizopetalus
Common Name: Japanese Lantern, Spider Hibiscus
Family Name: Malvaceae
Native to: Kenya, Tanzania, and Mozambique

The red or pink flowers of this Hibiscus are distinctive in their frilly, finely divided petals that curve up and create a globe shape. A long reproductive column protrudes from the center of the petals. The column is covered with stamens, the part of the flower that produces pollen. At the tip of the column are stigmas, where pollen lands and starts the fertilization process.

Hoffmannia ghiesbreghtii
Common Name: Taffeta Plant
Family Name: Rubiaceae
Native to: Guatemala and Southern Mexico

The common name taffeta plant refers to the satin, taffeta fabric-like texture of the leaves. The elongated leaves of H. ghiesbreghtii are dark green on top and dark red underneath. The yellow flowers are star-shaped with a red spot and are arranged in clusters along the stems.  There are about 100 species of Hoffmannia, which are in the Rubiaceae family and related to the coffee plant.

Jasminum rex
Common Name: Royal Jasmine
Family Name: Oleaceae
Native to: Thailand

Jasminum is a genus of shrubs and vines in the olive family, Oleaceae. It contains around 200 species native to tropical and warm temperate regions of Europe, Asia, and Africa. Jasmines can be either deciduous (leaves falling in autumn) or evergreen (green all year round), and can be erect, spreading, or climbing shrubs and vines. This winter-flowering jasmine has some of the largest flowers in the family.

Magnolia liliifera
Common Name: Egg Magnolia
Family Name: Magnoliaceae
Native to: Cambodia, China, India, Indonesia, Lao, Malaysia, Papua New Guinea, Philippines, Singapore, Thailand, Vietnam

The egg magnolia is highly valued in Asia for its fragrance. The flowers are small relative to many species of magnolia, but the scent of the flowers is intense. When blooming, the fragrance of tropical fruit fills the air. The flowers grow on the upright tips of stems and last only a day. The common name ‘egg magnolia’ is derived from the egg-like shape of the blooms.

Medinilla
Family Name: Melastomataceae
Native to: Africa, Madagascar, Asia, and Pacific Islands

Medinilla is a genus of about 150 species in the family Melastomataceae. Most species are evergreen shrubs with white, pink, or orange flowers. The flowers are arranged on a panicle, a branched cluster of flowers. When pollinated, the plant bears showy berries. The leaves of many Medinilla species are arranged in a whorl or are alternating. This allows the maximum amount of sunlight to hit each leaf.

 The genus Medinilla was named in 1820 after J. de Medinilla, governor of the Mariana Islands, which are off the coast of the Philippines. There are more than 100 endemic species of Medinilla in the Philippines alone.

Musa
Common Name: Banana
Family Name: Musaceae
Native to: Southeast Asia and Australia

In horticulture, parthenocarpy (which literally means “virgin fruit”) is the natural or artificially induced production of fruit without fertilization of ovules. The fruit is therefore seedless. Seedlessness is seen as a desirable trait in edible fruit with hard seeds such as watermelon, clementines, grapes, and grapefruit. Bananas are another example of parthenocarpy, which explains how the Conservatory’s plantains and banana plants can bear fruit without a pollinator being present. The common banana is triploid, meaning it has three sets of chromosomes. Triploids cannot produce a functional seed, but they still develop good fruit through parthenocarpy. After the stalk has flowered and borne fruit, it dies.

So how does a banana plant reproduce? There are side shoots or suckers at the base of the main stalk, which can be removed and replanted.  Banana flowers are protected by bracts. The bracts fold away one-by-one and reveal hundreds of flowers. Female flowers appear first and develop into hands of fruit. The male flowers emerge last and do not become fruit. In Southeast Asia the male flowers are boiled and eaten as a vegetable. Bananas are cultivated in 135 tropical and subtropical countries.

Oncidium
Common Name: Dancing Lady Orchid
Family Name: Orchidaceae
Native to: Cental and South America

Some species of Oncidium have long bouncing stems with abundant flowers that flutter in the breeze and look like male bees. Pollination occurs when actual angry male bees attack the flowers thinking they are a competitor. The common name, dancing lady orchid, refers to the elaborate lip that looks like a dress with a full skirt. The petals and sepals look like the arms and head of a tiny lady. The Greek word “onkos” means pad or mass and refers to the fleshy, warty callus on the lip of many species. Some calluses are known to provide oil droplets, which are consumed mainly by bees.

Phoenix roebelenii
Common Name: Pygmy Date Palm
Family Name: Arecaceae
Native to: Southeast Asia

The Conservatory’s pygmy date palm is a prized relic from the Panama-Pacific International Exposition. The Expo was held over 100 years ago in 1915. This elegant arching palm was donated to the Conservatory after the closing of the exposition. Each pinnate leaf, or frond, has 100 narrow, shiny leaflets. When in bloom, it drops hundreds of tiny white flowers that blanket the ground of the gallery. 

In 1889 James O’Brien, one of the most famous horticulturists of the 19th century, named the palm “roebelenii” in honor of the German orchid collector Carl Roebelen who was the first to completely document the plant in Laos. The pygmy date palm quickly became popular in landscapes and collections for its attractive leaves and trunk. By 1915, this palm would have been a common hot house plant.

Psidium cattleianum
Common Name: Strawberry Guava
Family Name: Myrtaceae
Native to: Brazil

Psidium cattleianum is a small tropical evergreen tree that in the same family as the common guava, Psidium guajava. The fleshy fruit of the strawberry guava turn purple or red as the fruit matures; some varieties of Psidium cattleianum have yellow fruit. The fruit is edible and juicy with a strawberry-like flavor. The upper surface of the leaves is dark green and glossy, while the lower surface is whitish green in color and punctuated with small oil cavities that give it aromatic qualities.

Strawberry guava is native to the coastal areas of eastern Brazil, where it is known as “araçá”. However, the tree quickly adapts to a variety of climates and is considered an invasive weed in many tropical areas, particularly Hawaii and the Caribbean islands. The strawberry guava was brought to Hawaii in 1825 for its fruit and ornamental attributes; however, it now threatens Hawaii’s native forests. The strawberry guava grows in monotypic stands that displace native tree species. Psidium cattleianum quickly spreads both by shoots and seeds, with the help of non-native birds and pigs that consume the fruit and spread the seeds to new areas. Restoration efforts are underway in Hawaii to control the growth of P. cattleianum and restore native forest species.

Verschaffeltia splendida
Common Name: Seychelles Stilt Palm
Family Name: Arecaceae
Native to: Seychelles

Verschaffeltia splendida is only found on three islands in the Seychelles where it is threatened by habitat loss. This canopy or understory palm grows in moist rainforests on steep hillsides and ledges. The stilt root system is thought to have evolved to stabilize the palm on steep slopes and in strong winds. The spikes on the trunk of the palm protect it from hungry animals.

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Whether you’re a native San Franciscan, a visitor from another side of the world, or a classroom of budding botanists, the Conservatory of Flowers offers an intimate up-close experience with rare and endangered plants unlike any other. Come see what treasures await you!

Golden Gate Park | 100 John F. Kennedy Drive | San Francisco, CA 94118| 415-831-2090