These plants that flowered in 1999 were mainly the cohort from seed produced in 1997.
(These plants; flowered; T:in 1999) (These plants that flowered in 1999; were mainly; the cohort from seed) (seed; produced; T:in 1997)
These plants These plants that flowered in 1999 seed
flowered were mainly produced
T:in 1999
the cohort from seed
T:in 1997