Nurse Shark
Shallow coral and rocky reefs, sand flats, seagrass beds and mangrove channels from intertidal pools to ≈ 70 m; in Costa Rica abundant around Isla del Caño, Golfo Dulce, Bahía Culebra, and Caribbean patch reefs of Cahuita.
Medium‑sized evergreen tree (10–20 m tall) with a single, often crooked trunk up to 80 cm DBH and grey‑green, finely fissured bark. Leaves simple, glossy, elliptic to obovate (10–25 × 4–10 cm), aromatic when crushed. Inflorescences are paniculate cymes bearing numerous small, yellow‑green, bisexual flowers (~6 mm Ø) with six tepals and nine stamens; flowers exhibit protogynous dichogamy (Type A or Type B) to promote out‑crossing. Fruit is a large, single‑seeded berry (botanically) 7–30 cm long, weight 150 g – 1.5 kg, with leathery exocarp and oily mesocarp (15–30 % lipids); seed spherical 3–6 cm Ø. Three horticultural races—Mexican, Guatemalan, West Indian—differ in skin texture, oil content and cold tolerance.
10–20 m height; trunk up to 0.8 m DBH
Several Hundread Kilos
60–80 yr (productive life 20–40 yr)
Not applicable (monoecious)
Not applicable (monoecious)
Seed‑grown trees 4–6 yr; grafted cultivars 2–3 yr
In Costa Rica main bloom Nov – Feb (dry season)
ruit maturation 6–8 mo post‑anthesis
Medium‑sized evergreen tree (10–20 m tall) with a single, often crooked trunk up to 80 cm DBH and grey‑green, finely fissured bark. Leaves simple, glossy, elliptic to obovate (10–25 × 4–10 cm), aromatic when crushed. Inflorescences are paniculate cymes bearing numerous small, yellow‑green, bisexual flowers (~6 mm Ø) with six tepals and nine stamens; flowers exhibit protogynous dichogamy (Type A or Type B) to promote out‑crossing. Fruit is a large, single‑seeded berry (botanically) 7–30 cm long, weight 150 g – 1.5 kg, with leathery exocarp and oily mesocarp (15–30 % lipids); seed spherical 3–6 cm Ø. Three horticultural races—Mexican, Guatemalan, West Indian—differ in skin texture, oil content and cold tolerance.
| Primary producer; flowers provide nectar/pollen for bees (Apis spp., Trigona spp.); fruits eaten by quetzals, trogons and mammals, facilitating seed dispersal. |
“Social” Traits & Reproductive Behaviour
(plants have no social groups, so key behavioural ecology is outlined instead)
Reproductive strategy: insect‑pollinated, protogynous dichogamy; flowers open first as female, close, then reopen the next day as male (Type A or B), promoting cross‑pollination.
Pollinators: chiefly stingless bees (Tetragonisca angustula), honey bees (Apis mellifera), hoverflies and hummingbirds at higher elevations.
Dispersal: in wild stands, large frugivores (quetzal, kinkajou, agouti) swallow the pulp and deposit intact seeds > 100 m from the parent.
Clonal propagation: most orchards use grafting; scion–rootstock compatibility creates functional “chimera” individuals with shared vascular communication.
Phenology: flowering peaks in the late dry season (Nov – Feb), fruit matures 6‑8 months later; canopy leaf‑flush synchronized with onset of rains, reducing self‑shading.
Avocado fruit is botanically a berry containing a single large seed.
Mesoamerican peoples cultivated avocados >5 000 years ago; the word derives from Nahuatl āhuacatl (“testicle”).
Flowers open twice on successive days (female first, then male), a unique pollination strategy among fruit trees.
Oil‑rich pulp (mainly oleic acid) confers high energy but low sugar, allowing diabetic‑friendly consumption.
Three horticultural races (Mexican, Guatemalan, West Indian) hybridise freely, giving rise to modern cultivars like ‘Hass’.
Shallow coral and rocky reefs, sand flats, seagrass beds and mangrove channels from intertidal pools to ≈ 70 m; in Costa Rica abundant around Isla del Caño, Golfo Dulce, Bahía Culebra, and Caribbean patch reefs of Cahuita.
