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Full-Text Articles in Botany

Life History, Sexual Dimorphism And 'Ornamental' Feathers In The Mesozoic Bird Confuciusornis Sanctus., Winfried S. Peters, Dieter Stefan Peters Sep 2009

Life History, Sexual Dimorphism And 'Ornamental' Feathers In The Mesozoic Bird Confuciusornis Sanctus., Winfried S. Peters, Dieter Stefan Peters

Winfried S. Peters

The life history of Confuciusornis sanctus is controversial. Recently, the species’ body size spectrum was claimed to contradict osteohistological evidence for a rapid, bird-like development. Moreover, sexual size dimorphism was rejected as an explanation for the observed bimodal size distribution since the presence of elongated rectrices, an assumed ‘male’ trait, was uncorrelated with size. However, this interpretation (i) fails to explain the size spectrum of C. sanctus which is trimodal rather than bimodal, (ii) requires implausible neonate masses and (iii) is not supported by analogy with sexual dimorphisms in modern birds, in which elongated central rectrices are mostly sex-independent. Available …


Genetic Change Following Fire In Populations Of A Seed-Banking Perennial Plant, Rebecca W. Dolan, Pedro F. Quintana-Ascencio, Eric S. Menges Apr 2009

Genetic Change Following Fire In Populations Of A Seed-Banking Perennial Plant, Rebecca W. Dolan, Pedro F. Quintana-Ascencio, Eric S. Menges

Rebecca W. Dolan

Disturbances such as fire have the potential to remove genetic variation, but seed banks may counter this loss by restoring alleles through a reservoir effect. We used allozyme analysis to characterize genetic change in two populations of the perennial Hypericum cumulicola, an endemic of the fire-prone Florida scrub. We assessed genetic variation before and 1, 2, and 3 years after fire that killed nearly all aboveground plants. Populations increased in size following fire, with most seedlings likely recruited from a persistent seed bank. Four of five loci were variable. Most alleles were present in low frequencies, but our large sample …


A New Species Of Streptanthus (Brassicaceae) From Three Peaks In Lake County, California, Rebecca W. Dolan, Richard O'Donnell Apr 2009

A New Species Of Streptanthus (Brassicaceae) From Three Peaks In Lake County, California, Rebecca W. Dolan, Richard O'Donnell

Rebecca W. Dolan

Streptanlhus vernalis is a newly described species inhabiting serpentine rock outcrops in the Three Peaks area in Lake County, California. Morphological and allozyme data indicate that this taxon is related to the S. morrisonii complex.


Life In The Slow Lane: Palmetto Seedlings Exhibit Remarkable Survival But Slow Growth In Florida's Nutrient-Poor Uplands, W. G. Abrahamson, C. R. Abrahamson Dec 2008

Life In The Slow Lane: Palmetto Seedlings Exhibit Remarkable Survival But Slow Growth In Florida's Nutrient-Poor Uplands, W. G. Abrahamson, C. R. Abrahamson

Warren G. Abrahamson, II

The palmettos Serenoa repens and Sabal etonia are crucial foundation species in many peninsular Florida vegetative associations. We monitored the survival and growth of individual palmetto seedlings using two cohorts found in different vegetative associations. Seedling cohorts containing both S. repens and S. etonia were individually tagged in 1989 and have been monitored until 2008, a period of 19 years. One cohort (N = 100 seedlings) occurs in a xeric, “inopina-phase” scrubby flatwoods and a second cohort (N =78 seedlings) lives in a well-drained, “wiregrass-phase” flatwoods. The soils at both sites are very nutrient-poor Entisols that show rapid permeability, low …