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Abstract Vegetative branching is common in the palms (Arecaceae). However, current terms to describe vegetative branching diversity are not consistent and do not cover the full range of branching types. [...]

Species of Eleocharis are prominent in aquatic and wetland habitats and serve as models for study of physiological adaptations to aquatic environments. The genus has an unusual morphology because the major photosynthetic organ is the stem. In order to define an architectural model for the genus to understand the evolution of this morphology, we examined mature morphology and development of E. cellulosa in living and fixed material using light and scanning electron microscopy. Eleocharis cellulosa has sympodial, vertical shoots that produce the photosynthetic culms and horizontal shoots that mix monopodial and sympodial development. Each sympodial unit produces three bracts, an elongated photosynthetic internode, then a fourth bract and an inflorescence that either aborts on vegetative culms or expands on reproductive culms. On each sympodium, the first bract subtends a precocious axillary bud that reiterates the sympodial unit; the second bract subtends a bud that develops the horizontal shoot. In both horizontal and vertical shoots, the internode below the second bract is produced by both the second bract and the renewal shoot. Sympodial growth is present in seedlings. In other species of Eleocharis. the structure of the sympodial unit is conserved but morphological diversity develops from variation in horizontal shoot growth. Key words: branching; Cyperaceae; Eleocharis elongata; Eleocharis geniculata; Everglades; southern Florida, USA; shoot dimorphism; sympodial.

Sawgrass, Cladium jamaicense, is the dominant macrophyte in the Florida Everglades. We examined sawgrass flowering phenology and compatibility reactions in ex situ and in situ populations over 2 yr. Sawgrass flowers in May in southern Florida. Flower maturation was relatively synchronous within an inflorescence. Along the entire inflorescence, functionally male flowers emerged initially, followed by stigmas, then anthers of hermaphroditic flowers. Flowers of each sex expanded over 2 d with less than 1 d in between, totaling 6-7 d for an inflorescence to complete flowering. Hand pollinations showed that sawgrass was self-compatible and not pollen-limited, because open pollinations produced fruit set similar to self- and cross- pollinations. Fruit set was low in autogamy and manipulation treatments. Manipulation treatments were used to study the effect of exposure to airborne pollen during hand pollinations. This treatment thus provides a useful technique for studies on the in situ compatibility of wind-pollinated graminoids. Sawgrass was able to self-fertilize, but the timing of flower maturation on an inflorescence promoted outcrossing. Actual outcrossing rates in sawgrass thus depend on clonal architecture and the timing of floral maturation on other inflorescences within a clone rather than on inflorescences of other genets in a population. Key words: anemophily; Cyperaceae; Everglades; protandry; protogyny; sawgrass; self-compatibility; wind pollination.

The extremely invasive Old World Climbing Fern, Lygodium microphyllum, has invaded New World tropical and subtropical habitats. Lygodium microphyllum has indeterminate twining leaves that grow up on and shade out host shrubs and trees, their epiphytes, and the understory. This invasive plant threatens numerous native habitats in Florida USA and the Caribbean, including internationally valued conservation lands such as Everglades National Park. Fire, which can reduce or stimulate growth and/or reproduction in different plant species, is one intervention used to manage L. microphyllum, but the effects of burning on this species' growth are unknown. We experimentally burned greenhouse-grown plants, then monitored their growth in response to burning for 18 months. We also clipped a subset of the greenhouse plants to determine whether fire effects were explained by aboveground biomass removal. In our experiment, fire either killed or reduced the regrowth of L. microphyllum plants. Burning killed 25% of the burned plants and slowed growth of the remaining burned plants for up to 18 months post-burn. Size had a significant effect on plant mortality: smaller burned plants had greater mortality than larger plants. Mechanically removing the aboveground biomass (leaves) by clipping did not kill any plants but reduced their growth as compared to controls in the first six months after treatment. Clipped plants, however, had substantially recovered after 12 months. Burned plants were more sensitive to drought than clipped or control plants. The results show that burning does more than remove biomass, compromising the root system and perhaps damaging the hydraulic support system, similar to the latent mortality effects of fire on forest trees. We discuss how fire could affect invasion by this species, incorporating fire effects on spore viability and dispersal, as well as on subsequent plant regrowth. These results show that fire is a useful management tool for L. microphyllum invasions that both kills plants and reduces plant regrowth for up to 18 months. [ABSTRACT FROM AUTHOR]

Premise: The southern Florida Everglades landscape sustains wetlands of national and international importance. Sawgrass (Cladium jamaicense), the dominant macrophyte in the Everglades, has two phenotypes that vary in size and density between Everglades marl prairies and peat marshes. Marl prairies have recently been hypothesized to be a newly formed habitat developed after European colonization as a result of landscape‐scale hydrologic modifications, implying that sawgrass marl phenotypes developed in response to the marl habitat. We examined whether sawgrass wetland phenotypes are plastic responses to marl and peat soils. Methods: In a common‐mesocosm experiment, seedlings from a single Everglades population were grown outdoors in field‐collected marl or peat soils. Growth and morphology of plants were measured over 14 mo, while soil and leaf total nitrogen, total phosphorus, total carbon, and plant biomass and biomass allocation were determined in a final harvest. Results: Sawgrass plant morphology diverged in marl vs. peat soils, and variations in morphology and density of mesocosm‐grown plants resembled differences seen in sawgrass plants growing in marl and peat habitats in Everglades wetlands. Additionally, sawgrass growing in marl made abundant dauciform roots, while dauciform root production of sawgrass growing in peat was correlated with soil total phosphorus. Conclusions: Sawgrass from a single population grown in marl or peat soils can mimic sawgrass phenotypes associated with marl vs. peat habitats. This plasticity is consistent with the hypothesis that Everglades marl prairies are relatively new habitats that support plant communities assembled after European colonization and subsequent landscape modifications. [ABSTRACT FROM AUTHOR]

Clonal growth can vary under different environmental conditions, and differences in clonal growth in the juvenile stage influence adult architecture. Acoelorrhaphe wrightii, a threatened palm in Florida, can occur as solitary or clonal. In order to predict its adult architecture, we determined the effects of water and light on (1) germination and (2) morphology of A. wrightii during juvenile life stages. Germination of wild‐collected seeds exposed to four conditions–subsurface, saturated, low, and high water levels–was monitored every month for a year. Seeds began to germinate after seven months; soils with saturated water levels had highest seed germination. Sixty‐four juveniles were grown in one of four environmental treatments (low water + sun, low water + shade, high water + sun, and high water + shade) and growth was measured every two months for a year. After a year, individuals were harvested to assess the impact of treatments on plant biomass. Low water + sun yielded juveniles with a greater number of leaves, more root mass and more branches. The results of this study suggest that A. wrightii requires a dry‐down in order to recruit successfully. Results were used to model the effect of water level on adult vegetative architecture. [ABSTRACT FROM AUTHOR]

Coastal plant communities are being transformed or lost because of sea level rise (SLR) and land-use change. In conjunction with SLR, the Florida Everglades ecosystem has undergone large-scale drainage and restoration, altering coastal vegetation throughout south Florida. To understand how coastal plant communities are changing over time, accurate mapping techniques are needed that can define plant communities at a fine-enough resolution to detect fine-scale changes. We explored using bi-seasonal versus single-season WorldView-2 satellite data to map three mangrove and four adjacent plant communities, including the buttonwood/glycophyte community that harbors the federally-endangered plant Chromolaena frustrata. Bi-seasonal dataweremore effective than single-season to differentiate all communities of interest. Bi-seasonal data combined with Light Detection and Ranging (LiDAR) elevation datawere used tomap coastal plant communities of a coastal stretchwithin Everglades National Park (ENP). Overall map accuracy was 86%. Black and red mangroves were the dominant communities and covered 50% of the study site. All the remaining communities had ≤10% cover, including the buttonwood/glycophyte community. ENP harbors 21 rare coastal species threatened by SLR. The spatially explicit, quantitative data provided by our map provides a fine-scale baseline for monitoring future change in these species’ habitats. Our results also offer a method to monitor vegetation change in other threatened habitats. [ABSTRACT FROM AUTHOR]