Plants growing on seabird-nesting islands are uniquely adapted to deal with guano-derived soils high in N and P. Such ornithocoprophilous plants found in isolated, oceanic settings provide useful models for ecological and evolutionary investigations. The current study explored the plants found on Mount Desert Rock (MDR), a small seabird-nesting, oceanic island 44 km south of Mount Desert Island (MDI), Hancock County, Maine, U.S.A. Twenty-seven species of vascular plants from ten families were recorded. Analyses of guano-derived soils from the rhizosphere of the three most abundant species from bird-nesting sites of MDR showed significantly higher (P < 0.05) NO₃⁻, available P, extractable Cd, Cu, Pb, and Zn, and significantly lower Mn compared to soils from the rhizosphere of conspecifics on non-bird nesting coastal bluffs from nearby MDI. Bio-available Pb was several-fold higher in guano soils than for background levels for Maine. Leaf tissue elemental analyses from conspecifics on and off guano soils showed significant differences with respect to N, Ca, K, Mg, Fe, Mn, Zn, and Pb, although trends were not always consistent. Two-way ANOVA indicated a significant interaction between species and substrate for Ca, Mg, Zn, and Pb tissue accumulation, showing that for these four elements there is substantial differentiation among species found on and off of guano soil. A compilation of species lists from other important seabird-nesting islands in the region suggested an ornithocoprophilous flora for northeastern North America consisting of 168 species from 39 families, with Asteraceae (29 taxa; 17.3%), Poaceae (25 taxa; 14.9%), Polygonaceae (10 taxa; 5.95%), Caryophyllaceae (9 taxa; 5.4%), and Rosaceae (9 taxa; 5.4%) as the most species-rich families. The taxa were predominantly hermaphroditic (69%) and perennial (66%) species, native (60%) to eastern North America.

A floristic inventory of vascular plants for The Nature Conservancy's Tiger Creek Preserve and Saddle Blanket Scrub Preserve, on the Lake Wales Ridge, Polk County, Florida, was conducted from August 2004 through February 2008. The 2308 combined hectares of the Preserves yielded 553 taxa, of which 54 are non-native, 37 are at or near the southern or northern limits of their ranges in Florida, and 24 are new Polk County records. Fifty-five taxa endemic to Florida were found, of which 27 are restricted to Florida peninsular scrubs or scrub/sandhill ecotonal habitats. Nine of these taxa are restricted to four or fewer counties. Twenty-seven are listed in Florida as endangered, threatened, or of management concern, and 18 are listed federally. Twelve plant communities are characterized: scrub, scrubby flatwoods, sandhill, xeric hammock, mesic flatwoods, wet flatwoods, bayhead, seepage slope, depression marsh, floodplain wetlands, blackwater stream, and ruderal. Descriptions and photographs of the plant communities are provided.

An analysis of the vascular epiphytes of El Triunfo Biosphere Reserve was made based on eight years of field work and herbarium data. Four hundred and sixty five species and infraspecies of vascular epiphytes from 131 genera and 31 families are listed. Approximately 9% were found to be true epiphytes, whereas 0.65% were accidental epiphytes. Orchidaceae was the most species-rich family, although the genera Peperomia, Tillandsia, and Polypodium were the most rich in epiphytes.

The two names proposed by C. C. Huang in 1991, Atalantia fongkaica and Fortunella bawangica, were not validly published because the herbarium in which the types were deposited was not specified. These names are validated here.