Fruit Biology or Ecology
Including examples from local flora and
David Attenborough’s Private Life of Plants
Characteristics of fruits and seeds
-mature ovary usually forms fruit and ovules
grow into seeds with embryo surrounded by
stored nutrients and protected by a seed coat
-function in dispersal and dormancy
Dormancy protects plants during cold seasons
or drought
-resistant seed coat that prevents germination
or hormones that inhibit germination
Dry-Indehiscent fruits
-may be classified by degree fusion between seed and fruit
GrainAcheneNut-
Dry Dehiscent Fruits
-may be classified by number of times fruit splits
FollicleLegumeSilicle or siliqueCapsule-
Quercus kelloggii Yellowstone
Acer macrophyllum
Olympic National Park
Fleshy Fruits
Collective term for fruit layers is pericarp. Exocarp is outer layer,
Mesocarp in the middle, and endocarp in the center of the fruit.
BerryPepoDrupePome-
Importance of Dispersal
Mobility in plants occurs during pollination
and fruit and seed dispersal
Mobility promotes gene flow and increases
genetic diversity
Ecological Classes of Dispersal
1. Zooichory2. Anemochory3. Hydrochory-
Three types of zooichoric dispersal
1. Epizooic- dispersed by _____ to
animals
2. Synzooic- dispersal by being _____ by
animals
3. Endozooic- dispersal from _____ an
animal
Examples of Epizooichory
Fruits with spines, prickles or uncinate
and/or hispid pubescence
Asteraceae- prickly achenes
Xanthium cocklebur Pgs. 431-432
Burdock fruits catching in dog’s hair on
Private Life of Plants video
Examples of Epizooichory
Poaceae
Cenchrus grass bur Pgs. 1253-1255
-involucre of spines and hispid hairs
surround grain
Examples of Epizooichory
Fabaceae
Medicago bur clover Pgs. 672-675
-legumes spirally coiled with prickles
Examples of Epizooichory
Proboscidea Devil’s claw Pgs. 104, 878-880
-capsule with two hooks that attach to
mammals and disperse seeds from multiple
openings in fruit
-similar to grapple pod that co-evolved with
ostriches on Private Life of Plants video
Epizooichory and Sticky Seeds
-fruits may swell and expel seed in burst of
water similar to squirting cucumber on
Private Life of Plants video
Viscaceae mistletoe
Phoradendron Pgs. 1064-1067
-birds eat fruits and wipe beaks on bark
-Western USA mistletoes that explode when
swell from bird body heat and bird flies away
with seeds stuck to feathers and later preens
scraping seeds on bark with beak
Examples of Synzooichory
-animals like rodents that form food caches
Asteraceae
-_____ from a variety of plants are stored
in caches
Juglandaceae Pgs. 744-751
Carya (hickory or pecan) and Juglans
(walnut)
-_____ cached by squirrels
Example of Synzooichory from Private Life
of Plants video
Brazil nut in South America must be chewed
open by rodent called Agouti that caches
seeds
Examples of Endozooichory in Birds
-as in flower color, they like red, dark or
yellow fruits with little odor
Magnoliaceae- Magnolia
-red seeds released from aggregates of
follicles
Solanaceae- Physalis berries Pgs 10231025
Cactaceae-red berries Pgs. 482-494
Rosaceae-many red berries, pomes, and
drupes. Often ripen over a period of time to
use many different animals
Anacardiaceae-sumac drupes Pgs. 232-235
Example of Endozooichory in birds
from Private Life of Plants video
Tropical figs are yellow and attract monkeys
and birds. Monkies destroy fruits while birds
swallow whole.
Fruits the color of wattles (loose skin used
as sexual attractant in birds) attract the
flightless New Guinea cassowary
Example of Endozooichory in mammals
Fabaceae
Prosopis (mesguite) legumes Pgs. 688-689
-found in manure of cattle where they often
germinate
Bats like drab colors and strong odors from
large hanging fruits like Mangifera (mango)
Examples of Endozooichory in mammals
from Private Life of Plants video
Durion tree from Borneo (flowers pollinated
by fruit bats) attracts primates from km away
with terrible odor. Flesh of capsule tastes
like caramel crème
Rhino apple tree fruits dispersed in dung
Acacia legumes dispersed in elephant dung
in Africa. Elephants push over trees to get
legumes maintaining savannah
Anemochory
-often lightweight seeds or fruits
-seeds or fruits (samaras) may be winged
Three types of anemochoric dispersal
1. Flyers
2. Rollers
3. Throwers
Examples of anemochorous flyers
Orchidaceae- Pgs 1212-1222 SMIFNCT
-capsules with _____ seeds
Typhaceae Pgs. 1348-1351
-pubescent nutlets
Asteraceae-many species with _____ on achenes
Ex. Taraxacum (dandelion) Pgs. 418-419
Salicaceae- Pgs. 974-981
-capsules with hairy seeds in willows and
Cottonwoods
Ulmaceae- Pgs. 1038-1041
-samaras
Examples of anemochorous rollers
-commonly called tumbleweeds
-many families have species that are
commomly called tumbleweeds but Salsola
tragus (Pgs. 540-542) or Russian thistle is
most common
-annuals that die and break off and roll
dispersing seeds
-Bird Cage Plant in Private Life of Plants
Video disperses seeds in this way over
desert dunes
Examples of anemochorous throwers
Fabaceae
-some species of Vicia (vetch Pgs. 706-709)
and Lupinus (bluebonnet Pgs. 671-673)
have _____ that twist throwing seeds out
from parent plant
-poricidal _____ in Papaveraceae (Pgs.
872-877
-Touch-me-nots that throw seeds on Private
Life of Plants video
Hydrochory
-often lightweight seeds or fruits
-seeds or fruits buoyant utilizing air spaces
or fibers
Two types of hydrochoric dispersal
1. Rain splash cups
2. Floaters
Examples of Hydrochory-Rain Splash cups
-probably in capsules of many species but
has been documented in Sagina capsules
(Pgs 522-524) Caryophyllaceae
and dispersal of nutlets (Pgs 779-781) Lamiaceae
Scutellaria drummondii and S. wrightii
Examples of Hydrochory- floaters
Arecaceae (Palm Family) Cocos
-fibrous mesocarp allows it to float for hundreds of miles
and colonize islands
Fabaceae (Pea)
Sea Bean on Private Life of Plants video on islands of
northern Australia. Occasional on Padre Island in TX
Cyperaceae (Sedge) sac-like perigynium around
achene allows them to float Pgs 1104-1111