Commelinaceae
This family of herbs is often succulent and frequently
has cymose flowers, which sometimes have a boat-shaped spathe. The simple
leaves are alternate, parallel veined and usually have a closed sheathing
base. The flowers are bisexual and actinomorphic or zygomorphic. The
fruit is a loculicidal capsule or indehiscent. Species include the Dichorisandra
thysiflora, or blue ginger, Tradescantia virginiana, or spiderwort,
and Zebrina pendula, or the wandering Jew.
Dichorisandra thyrsiflora
Cycadaceae
These plants are woody, un-branched or sparsely branched,
palm-like, dioecious trees or shrubs. Although cycads look like a cross
between palms and ferns they are more closely related to conifers. The
cones can be yellow, scarlet, maroon, orange, or apricot and are not
produced every year by the female because the process takes an enormous
amount of energy. Heat is generated by the cones to attract weevils,
which help pollinate. A species in Indonesia have cones that smell so
bad that locals chop them down and bury them. Leaves are compound, alternate,
and spirally arranged to cluster at the stem. The leaves are also frond-like,
stiff and typically have a single mid-vein. The seeds, stems, and leaves
of many cycads contain a neurotoxin potent enough to paralyze cattle
or cause Alzheimer’s-like effects in humans. This family is found
in tropical and subtropical areas. A few species are in Costa Rica and
are very common in the fire climax woodlands of Australia.
Cycas revolute..........................Cycas circinalis
Euphorbiaceae
Euphorbiaceae are mostly paleotropical. They can be monoecious
or dioecious. The flowers are actinomorphic. The fruit is usually a
capsular schizocarp, which is a fruit that splits at maturity into two
or more closed one-seeded parts. Euphorbiaceae are herbs, shrubs, and
trees. Many are cactus-like but with weaker spines and have a poisonous
milky sap. This family is one of the largest including 7,500 species.
Some can bear leaves that are simple or compound when well watered.
Most have alternate leaves but a few are opposite or whorled. The plant
Manihot esculenta is a shrub from Brazil that is widely cultivated in
the tropics for its roots provide a good source of starch. Another plant
in this family is Euphorbia splendens, also known as Euphorbia millii,
an ornamental shrub from Madagascar that legend says had white bracts
until the plant was worn as a “crown of thorns” by Christ,
turning the bracts red.
Euphorbia baivensis............................Euphorbia tirucalli...............................Euphorbia
milii
Euphorbia canariensis (foreground) with Euphorbia trigona
(background & closeup, right)
Fabaceae (Leguminosae)
Legumes are a significant component of nearly all terrestrial biomes
and comprise one of the largest families of flowering plants. Species
range from dwarf herbs of arctic and alpine vegetation to massive trees
of tropical forests. Common species that are seen all over campus are
the Bird’s Foot Trefoil and the White Clover. The unifying characteristic
of the family is the fruit, a pod, known as the Legume. It is designed
to encourage dispersal by animals, wind, and water. Leaves are typically
pinnately compound. Many Legumes convert atmospheric nitrogen into nitrogenous
compounds useful to plants. This is accomplished by the presence of
root nodules, which contain the bacteria of the genus Rhizobium. A symbiotic
relationship is formed where nitrogen is fixed for the plant and the
plant gives carbon that is fixed by photosynthesis, allowing the Legume
to survive in poor nitrogen conditions. There are three sub-families:
Papilionoidae, Caesalpinioidae, and Mimosoidae. Papilionoidae is the
largest of the three sub-families and the most widespread. The majority
of the species are herbaceous, but there are a few trees and shrubs.
Papilionoidae are recognized for their butterfly-like flowers, which
are zygomorphic. Two of the five petals are fused together to form a
boat-shaped keel and two petals form wings, while the last is a banner
petal. Most of the important crop species are in this sub-family including
Glycine max (Soya bean), Pisum sativum (common pea), Cicer arietinum
(chickpea), Phaseoulus vulgaris (French bean), Lens culinaris (lentil),
and Arachis hypogaea (peanut). Caesalpinioidae are mostly tropical or
subtropical trees and shrubs. Root nodules are rarely formed in Caesalpinioidae.
The flowers are zygomorphic and have five petals but do not distinguish
themselves as in the former subgroup. The stamens are visible externally.
Several species are popular ornamentals such as the Delonix regia, whose
common name is Flamboyant, and Caesalpinia pulcherrima, known as Barbados
Pride. Senna alexandrina is a commercially grown medicinal plant for
its purgative qualities. The sub-family Mimosoidae is also mostly tropical
and subtropical shrubs and trees. The characteristic defining this sub-group
is its small, actinomorphic flowers, which are crowned together into
spikes that resemble a pompom. The species Acacia are important economically
for timbers, extracts for tanning, and some yield a gum, which is used
in industrial processes. The Legume, Leucaena leucocephala, known also
as Leadtree has a nutritive value equal or superior to alfalfa. Its
qualities have earned a favorable reputation in land reclamation, erosion
control, water conservation, reforestation, and soil improvement programs.
The leaves are used as mulch on crops and can significantly increase
yields. The seeds are strung into beads for various items of jewelry
and sold to tourists in Puerto Rico and the Virgin Islands. In the Philippines,
the young pods are cooked as a vegetable and seeds are used as a substitute
for coffee. Ripe seeds can be eaten like popcorn. The Leadtree is planted
to provide shade for crops such as coffee, vanilla, cocoa, and black
pepper. The wood is heavy and used for fuel or charcoal. In Latin America
the bark of the Leadtree is used medicinally to ease internal pain.
A decoction of the root and bark is taken as a contraceptive, ecbolic,
or depilatory. Another species of Legume, Enterolobium cyclocarpum,
also known as corotu or Guanacaste, is the national tree of Costa Rica.
This tree is one of the largest trees in the dry forest of Central America,
reaching 3m in diameter and up to 40m in height with a large spreading
crown. A providence in Costa Rica is named after this tree because they
are abundant over the countryside, creating a distinctive landscape.
The pods of the corotu resemble an ear in form; promoting common names
such as ear fruit, ear pod, and orejoni (from the Spanish word oreja
meaning ear). Like the Leadtree, Guanacaste is planted to shade livestock
or crops. Livestock also value this Legume because it produces a large
quantity of highly palatable and nutritious pods containing a sugary,
dry pulp. The wood has a similar appearance to walnut and is resistant
to attack from dry-wood termites. This makes it practical for house
construction. The pods and bark are used in soap making and medicinally
to fight colds and bronchitis. Fabaceae is a family useful for many
things.
Enterolobium contortisiliquum
Gesneriaceae
Gesneriaceae are herbaceous perennials or annuals, consisting
of shrubs, lianas, and trees. Twenty percent are epiphytic. This family
is primarily distributed in the tropics but there are a few temperate
species. Generally the leaves are opposite and many are “velvety”.
A well-known species is the African violet. The species of Episcia is
a creeping, tropical perennial native to Brazil, Columbia, Guinea, and
Surinam. It is a popular choice for hanging baskets. Another species
used in hanging baskets is the Columnea. These tropical plants are natives
of South America and form bushy plants with oval or lance-shaped leaves
that are dark green. The flowers are tubular and irregularly lobed.
Aeschynanthus x splendidus.......Diastema vexans........................Kohleria
cv. Longwood
Malvaceae
Although modern classification limits members of this
family to the mallows, abutilons, cotton, and hibiscuses, Malvaceae
once also included baobabs, kapok, kola, cacao, durians among others.
There are now a total of fifty genera and over 1,500 species characterized
by the presence of stellate (star-shaped) hairs and mucilaginious sap.
The flowers are typically bisexual and actinomorphic. Commonly the flowers
are large and trumpet shaped with a prominent bundle of stamens and
carpels. The species Hibiscus esculentus, “okra”, is edible
and releases a lot of mucus that gives gumbo its slimy consistency.
Montezuma speciosissima is a tree from Puerto Rico that is grown as
an ornamental elsewhere but provides durable timber for fence posts
and furniture as well. In Brazil the species Abutilon hybridum is found
and is known as the “Chinese Lantern”.
Abutilon "Moonchimes".............Hibiscus rosesinensis
Marantaceae
This family consists of perennial herbs that grow from
rhizomes. The leaves are alternate and the lateral veins on the blades
are parallel. The fruits are fleshy, dry capsules. Calathea insignis,
or Rattlesnake plant, belongs to this family. This species is bushy
with narrow, tapering erect foliage. Its leaves have wavy edges and
can grow to 18 inches long. The top of its leaf is pale green with dark
green blotches and its underside is a dark maroon.
Maranta leuconeura
Melastomataceae
This family is a taxon of dicotyledonous flowering plants
that is found mostly in the tropics. They are annual or perennial herbs,
shrubs, or small trees. Their leaves are distinctive, being opposite
with 3-7 longitudinal veins that rise from the base of the blade to
the tip of the leaf. A number of species are labeled invasive. An example
is Koster’s curse introduced in the 1940’s to the Hawaiian
Islands. The berries produced are loved by birds and are therefore spread
everywhere, making the plant difficult to control. Another species that
is invasive is the Miconia calvescens which is a tree that could take
over Hawaii’s forests. It has already claimed 60% of Tahiti’s
forests!
Moraceae
There are over 1,000 species in the Moraceae family comprising
of trees, shrubs, and rarely herbs. Most have a milky sap. Their leaves
are simple and alternate most of the time. The flowers are unisexual
and are densely aggregated. Male flowers have four stamens and the female
flowers have a bicarpellate pistil with two styles. The fruit types
are drupes and achenes. The Broussonetia papyrifera, or paper mulberry,
is a shrub or small tree that is native to East Asia. Its bark is converted
into fine cloth for skirts, capes, loincloths, sandals, bed cloths,
etc. Another genus is the Ficus, which includes figs and rubber plants.
Ficus carica, the edible fig, is an example and so is Ficus religiosa,
the Buddha Tree that is native to India. Buddha was supposed to receive
enlightenment under such a tree and a cutting of this plant dating to
288 BC still exists in Sri Lanka. A better known Ficus is the Indian
banyan tree, or Ficus benghalensis. It is the world’s largest
tree in terms of spread with some old trees covering up to an acre of
ground. “Banyan” refers to the merchants who set up shop
under the spreading trees, creating a meeting place for artisans, tourists
and children. Attractive red fruits and aerial roots hang from the limbs.
The reproduction system of the Ficus is unique. Each species has an
associated species of agaonid wasp that is the only way they can pollinate.
The wasps pollinate the plant and in turn the plant’s fruit is
the only place the wasp can lay their eggs.
Ficus sp.......................................Ficus benghalensis.....................Ficus
triangularis
Musaceae
Comprised of large tree-like perennial herbs, the Musaceae
have alternate leaves with concentric sheathing portions that create
pseudo-trunks from which the blades diverge. The blades have prominent
mid-rib and parallel lateral veins. The flowers are zygomorphic and
unisexual. The fruit is a berry and with a leathery separable ecocarp.
Musa x paradisiaca, the edible banana, is the seedless fruit of commerce.
Musa papadisiaca ssp. normalis, the plantain, is a form of cooking banana
or plantain.
Musa acuminata cv. Enanogigante
Myrtaceae
This family consists of trees and shrubs found in the
tropics, subtropics, and temperate regions. The leaves are usually opposite
and frequently glandular dotted. The flowers are actinomorphic and the
fruit is commonly a berry. The species Myrciaria cauliflora “Jaboticaba”
is a large cauliforous (flowers and fruits grow directly from the trunk
or branches instead of from the tips) tree with peeling bark. It is
cultivated in Brazil for its edible fruit. The species Psidium guajava
“guava” is a shrub from tropical America that has a lemon’s
shape and size. This fruit is pink or cream inside and used for jam,
jelly, and juice.
Eugenia sprengeri......................................Eugenia paniculata
Nyctaginaceae
These herbs, vines, shrubs, and trees are characterized
by the presence of betalains and p-plastids. The leaves are simple,
entire, epostulate, and usually opposite. The flower is bisexual. The
fruit is an achene. The genus Bougainvillea originates from South America
and contains species that are evergreen or deciduous. Petal-like bracts
hide the flowers of Bougainvillea. The actual flower is white and tubular.
This genus is named after the French navigator, Louis de Bougainville,
who first discovered these plants. Bougainvillea glabra or “Paper
Flower” is a vine in this genus.
Bouganvillea glabra
Webmaster:
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Photography by Rebecca Urban; Border Graphic by Ann Hull
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