The phrase "brown leaf" is correct and can be used in written English.
You could use it in a sentence like, "The wind blew the brown leaf across the pavement."
Symptoms of ash dieback, particularly the dieback of leaves with brown leaf stalks, will start showing in stricken trees over the next few weeks.
This exhibition presents just four, each representing a different stage in the life cycle of the magnolia tree: a short, dried twig; a fallen brown leaf; a new branch bearing bright-red berries; and a branch with luxuriant white blossoms.
Brown leaf splotches are an early symptom, but it is the larger cankers that develop on the main limbs and trunk what kill the tree, sometimes in just two years.
Because it can cause brown leaf spot and kill seedlings of mono- and dicotyledonous plants, TeA is regarded as a potential herbicidal agent.
For these sparsely vegetated sites during this dry year (1997), we found that the SAR signal was not significantly attenuated by sparse green vegetation cover (green leaf area index<0.35) and dense standing brown vegetation cover (brown leaf area index up to 1.5).
That night, as I was carrying the guest beddings up from the laundry, I noticed a large, strange brown leaf, lying on the floor next to my stove.
As I walked down the crunchy brown leaf-lined street on this quintessential fall election day, it was unseasonably warm, and the sun cranked up the saturation on the remaining autumnal leaves.
Usually found among vegetation rather than on the ground, a mantid may be disguised to resemble green or brown foliage, a dried leaf, a slender twig, a lichen, a brightly coloured flower, or an ant.
I CROUCHED over a wooden bench inside the rolling room in El Credito Cigars' factory in the Little Havana neighborhood of Miami, peering at a light brown tobacco leaf.
A roof panel had blown loose from one of the tanks and now hung, bent like a giant brown tropical leaf, halfway to the ground.
She heated a bowl of soup, built up the fire and huddled over it, while outside the temperature dropped, steadily, hour by hour, until a solitary brown oak leaf detaching itself from the tree fell onto the frost-hard ground with a crackle that echoed through the whole forest".
