Four years after a trench was dug through alpine habitat on Mount Washington, New Hampshire, we surveyed vascular plants, bryophytes, and lichens in the disturbed area, analyzing species richness and abundance compared with values in adjacent, undisturbed areas. Plants had begun recolonizing the disturbed area, but species richness and abundance remained far lower than in the undisturbed community. Among vascular plants, graminoids colonized most quickly, and woody species were largely absent. Species with the highest frequency and greatest abundance in the disturbed area also were common and abundant in the undisturbed community. Bryophytes appeared to be colonizing no more quickly than vascular plants. Treeline and elevation exerted separate effects on community structure and recovery. Treeline influenced species richness, abundance, and the rate of recovery of vascular plants, but there was no evidence of an additional effect of elevation either above or below treeline. Treeline also influenced species richness of bryophytes and lichens. In addition, elevation appeared to have a separate effect on their rate of recovery in alpine habitat: species richness of bryophytes and lichens declined with elevation in the disturbed community but not in the undisturbed community. This suggests that elevation has a transient effect on colonization and/or survival, but only above treeline. In general, recovery has occurred more quickly below treeline. This survey establishes baseline information that will be useful in assessing the rate of recovery after future surveys.

Recent molecular phylogenetic analyses have revealed that Saxifraga sect. Trachyphyllum as currently circumscribed is polyphyletic, with the designated type, S. aspera, falling outside of the more speciose clade. Several other lines of morphological, geographic, and ecological evidence also distinguish the two distantly related groups from one another. In combination, these data necessitate the circumscription of a new section, S. sect. Bronchiales, which is described herein. The section is hypothesized to have arisen in the southern Rocky Mountains of North America, followed by northwestward expansion across Beringia and diversification among refugia.

The morphology, taxonomy, ecology, distribution, and conservation status of the Oklahoma endemics, Leavenworthia aurea (Brassicaceae/Crucifereae) and Phlox pilosa subsp. longipilosa (Polemoniaceae) Pennell, are reviewed and supplemented with original pollen morphological descriptions that include comparisons to related taxa. These descriptions are considered extensions of the original taxonomic descriptions. Leavenworthia aurea is a glabrous winter annual found on limestone glades in Choctaw and McCurtain counties. The taxon is considered imperiled, with Natural Heritage rankings of G2S2. The pollen has three colpi with a reticulate surface enclosing polygonal lumina (openings within reticulations on the pollen surface) with lengths varying from 0.5–2.5 µm, that are either empty or contain inclined free standing columellae approximately 0.5–0.8 µm in height. Granules less than 0.5 µm in diameter also occur in some lumina, but are most common in the colpus. The reticulate surface of Leavenworthia pollen is similar to other Cardamineae, as well as to the pollen of other members of the Brassicaceae. Phlox pilosa subsp. longipilosa, found on granitic soils in the Quartz and Wichita mountains of Greer and Kiowa counties, is a branching spring perennial ranging from 20.0–45.0 cm in height. Like L. aurea, it is considered to be imperiled, with a Natural Heritage ranking of G2S2. Phlox pollen morphology has been broadly characterized but has not been described in P. pilosa subsp. longipilosa. The pollen of P. pilosa subsp. longipilosa is pantoporate and reticulate, with enclosed polygonal lumina often exceeding 5.0 µm. The exine (pollen surface) is multireticulate because all lumina, except those containing pores, enclose smaller reticulate networks composed of thin rods of sporopollenin. In porate lumina, sporopollenin rods are curved, with one end attached to the surrounding ridges, as they are in non-porate lumina; the other end either hangs freely above the pores or is attached to the pore margins. Pollen morphology is similar to well-established Phlox pollen types.

The morphology, taxonomy, ecology, distribution, and conservation status of the Oklahoma narrow endemics, Physaria angustifolia (Brassicaceae/Crucifereae) and Penstemon oklahomensis (Plantanginaceae), are reviewed and supplemented with original pollen morphological descriptions that include comparisons to taxa within their respective families. These descriptions are considered extensions of the original taxonomic descriptions, which lacked pollen morphology. Physaria angustifolia is an annual up to 4.0 dm in height found on limestone glades of southeastern Oklahoma and northeastern Texas. The taxon is considered imperiled in Oklahoma, with a state Natural Heritage rank of S2. The pollen has a reticulate surface and five apertures and is identical to most other members of the genus. Penstemon oklahomensis is a perennial herb 4.0–6.0 dm in height found throughout central Oklahoma and at a single site in Texas. The taxon is considered vulnerable, with a state Natural Heritage rank of S3. The pollen has a microreticulate surface with distinctive horizontal cracks across the colpal membrane, often isolating portions of the membrane. Although relatively uncommon in angiosperm pollen, such cracks are found in many members of the Lamiales.

An unusual temperate ridge–cliff–talus system exists at Rock Rimmon in urban Manchester, New Hampshire. Recent surveys and historical data indicate that five natural communities occur within the system, of which three are critically imperiled in New Hampshire: Appalachian wooded talus, pitch pine–Appalachian oak–heath forest, and pitch pine rocky ridge. The remaining two natural communities are occasional in the state: Appalachian oak–pine rocky ridge and temperate acidic cliff. Seven plant taxa previously or currently recorded at Rock Rimmon are rare (SH, S1, or S2) in New Hampshire; four other taxa are uncommon (S3) in the state. We re-located two previously recorded rare taxa during our 2012 survey. Digitaria filiformis var. laeviglumis, a globally rare crabgrass, is endemic to this biodiversity hotspot, but was not re-located. In addition, four other rare plant taxa were not re-located, and all are likely extirpated as a result of the lengthy history of human-related disturbance at the site. The temperate ridge–cliff–talus system closely corresponds to NatureServe's central Appalachian pine–oak rocky woodland system, which is distributed from Maine to Virginia west to Kentucky and Ohio. Xerophytic oak and pine dominate across the range of this system type, although many canopy species differ along a latitudinal gradient.