When looking for them, Burzycki finds a tiny plant that is just beginning to flower. It is Pinguicula pumila, a dwarf butterwort, which traps insects and dissolves them for nutrients that otherwise are unavailable in these poor soils. This plant is smaller than a half dollar, with flowers three-eighths of an inch across when fully open. Its will to live is far larger.

THE SCRUB

The peculiar charm of scrub is its rather taciturn attitude about charm. As an ecosystem, it is dry, sandy, open and short of stature. As much as any ecosystem, it demands that you work to appreciate it.

But great appreciation comes with the little flowers and oddball plants, and the way this flora works to stay alive on the infertile sands at its feet.

Scrub is Florida's oldest ecosystem. It kept its head above water when the seas were 20 feet higher some 100,000 years ago because it rears up on ancient sand dunes. The scrub runs down the state's central spine, and is found in dwindling pockets in Palm Beach County, not at all in Broward County and in two tiny spots in Miami-Dade. These are the fenced 15-acre plot called County Line Scrub on the Dade-Broward boundary and a nearby four-acre site unromantically dubbed Dolphin Center Park Addition.

The particular form scrub takes here is called scrubby flatwoods.

County Line Scrub is rather like Janus, the god with two faces: the northern section is oak-dominated, while the southern half remains in pines.

Hiking around the northern part, we find sand live oak, with leaf margins tightly curled under; Chapman's oak, with kite-shaped leaves and myrtle oak with roundish leaves. There's even an extraordinarily rare natural hybrid called Rolf's oak that's a cross between Chapman's oak and running oak.

Winged sumac, with its topknots of compound leaves, rises around the oaks and will supply abundant red fruit for small warblers and other wildlife in the fall. Sumac is a ruderal, meaning it grows on the edges of places in poor soils. Pawpaws also are peeking out from the edges of the oaks, looking for sun. Small woody plants, pawpaws are just beginning to produce flowers when we find then, but soon will open greenish petals that turn white.

Saw palmettos creep on their bellies beneath the pines and are joined by cocoplum, day flowers and wax myrtle, which has been dwarfed in the grayish sands.

Tarflower is an indicator species, meaning if you find it, you've found the scrub. Its botanical name is Befaria racemosa. Its flowers open seven wide-spreading sticky white petals, hence its name.

At the northern edge of its range is quailberry, Crossopetalum ilicifolium. Roundish leaves, pointed at the tips, with holly-like edges, along with red fruits, identify this miniature and endangered shrub.

There's a blueberry relative here, too, and rusty lyonia, which has copper-colored new leaves appealingly soft and fuzzy.

What is not here is fire. In the middle of this urban setting, it is excluded.

Lack of fire means the oaks are getting larger, while some rare plants -- the pawpaw reaching out from the edges -- are in danger of being shaded out. What also is not here is the scrub blue jay, because it needs a much larger territory. The same is true of the other scrub denizens such as gopher tortoise, scrub lizard, burrowing owl and the indigo snake.

However, there is a loop trail and a perimeter trail to take you through the little system, and you'll discover coontie, sabal palms and partridge pea and even native cactus, called Opuntia humifusa.