The ontogenetic growth model (OGM) of West et al. provides a general description of how metabolic energy is allocated between production of new biomass and maintenance of existing biomass during ontogeny. Here, we reexamine the OGM, make some minor modifications and corrections, and further evaluate its ability to account for empirical variation on rates of metabolism and biomass in vertebrates both during ontogeny and across species of varying adult body size. We show that the updated version of the model is internally consistent and is consistent with other predictions of metabolic scaling theory and empirical data. The OGM predicts not only the near universal sigmoidal form of growth curves but also the M(1/4) scaling of the characteristic times of ontogenetic stages in addition to the curvilinear decline in growth efficiency described by Brody. Additionally, the OGM relates the M(3/4) scaling across adults of different species to the scaling of metabolic rate across ontogeny within species. In providing a simple, quantitative description of how energy is allocated to growth, the OGM calls attention to unexplained variation, unanswered questions, and opportunities for future research.

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Question: What is the nature and relative importance of compositional gradients within‐ and between fens?Location: Iowa, USA.Methods: 506 0.5 m × 0.5 m quadrats were sampled from 31 fens across a 550 km extent. Presence/absence of all vascular plant taxa, plus the non‐vascular genera Sphagnum and Chara, and values for 24 environmental variables were noted. Global Non‐Metric Multidimensional Scaling and Monte Carlo tests were used to describe compositional variation and identify significant environmental co‐variables. Model‐based cluster analysis was used to identify the optimal number of groups supported by the data, while k‐means clustering was used to assign each quadrat to a group. The number of occurrences (and frequency) of each species within each group was calculated. Two‐dimensional 95% Gaussian confidence intervals, ANOVA, correlation coefficient homogeneity tests, log‐linear modelling, and Fisher's exact tests were used to document patterns of compositional change.Results: Two stable axes of variation were identified: the first being most closely correlated with soil pH, Mg, Ca, P, S, vegetation height, surface and −10 cm soil temperature, site area, perimeter, perimeter/area ratio, growing season, and air temperature, with the second being most correlated to soil moisture, N, disturbance level, % organic matter, hummock height, N‐S coordinate, and precipitation. Individual sites harboured between 20–47% of total compositional variation, with 28% of Axis 1 and 55% of Axis 2 scores being contained within‐sites. Five compositional regions were identified that differed in the proportion of calciphile and hydrophile species. Compositional groups differed significantly between geologic types.Conclusions: While the principal axis of variation (corresponding to the rich‐poor fen gradient) is present largely between sites, the second axis (corresponding to water level) is largely repeated within sites. Documentation and protection of vegetation patterns and species diversity within Iowa fens will thus require consideration of multiple sites across the landscape.

We report an additional five taxa to the Iowa flora based on new field collections or on re-examination of problematic specimens. With these additions, the Iowa pteridophyte flora now consists of 70 taxa, a surprisingly high total for a state originally about 85% prairie and now predominantly in intensive row-crop agriculture.Botrychium campestre W. Wagner & Farrar, Prairie Moonwort, is a North American endemic that occurs sporadically in the Great Plains of Canada and the United States. The Iowa plants were originally discovered growing in loess soils 0n i X n o r o C ^ eeP hUl PrairieS in WeStern Iowa ( pl y m °uth Co.) by Ted Van Bruggen in 1982. They were recognized as plants new to Iowa by Lawrence Eilers, studied by Donald Farrar (Proc. Iowa Acad. Sci., 1985), Florence Wagner, and Warren â"¢T* T i} T â"¢i de ^?" \t species (wagner & wa §ner ' Amer -Fern *• 76. [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] 1986). The Prairie Moonwort is encountered from late-April to mid-June when soil and climate conditions am mnrWatoH n {* â"¢â€ž, i „„. t b conditions are moderated. It is now known from counties in extreme western Iowa (Fremont Co.