Hybridization between Senecio smallii and S. tomentosus (Compositae) on the granitic flatrocks of the Southeastern United States
Senecio smallii andS. tomentosus occasionally hybridize on the granitic flatrocks of the Piedmont of the Southeastern United States. These hybrids are intersectional crosses between sectionsAurei andTomentosi. The parental species have different chromosome numbers withn = 22 inS. smallii andn = 23 inS. tomentosus. Meiosis in the hybrids is abnormal with 22ns and li or 2iis and 3is, and the percentage of stainable pollen is greatly reduced over that of the parents. The hybrid pollen grains are structurally abortive as demonstrated by the scanning electron microscope. Origin of the natural hybrids was documented by the production of artificial hybrids including F1’s, F2’s, and BC’s. Very few of the F2 seeds germinated, and all of the F2 seedlings later died, indicating hybrid breakdown. Seeds of the F1 and BC generations germinated well, and the seedlings were vigorous. Population samples indicate that there is some variation within the natural population systems; however, no evidence of introgression was detected. The isolating mechanisms and possible evolutionary effects of this natural hybridization are discussed.
A Revision of Senecio aureus Linn. and Allied Species
This study includes those temperate North American species of Senecio which are herbaceous perennials; which are glabrous or nearly so; which have one to several stems arising from a horizontal to suberect, fibrous-rooted caudex or rhizome; which have a cluster of petiolate basal leaves; and which have the cauline leaves progressively reduced upward. With the possible exception of several peripheral taxa, these species are believed to constitute an essentially natural assemblage. This concept approximates the section Aurei Rydb. (Bull. Torr. Bot. Club 27:173. 1900), and throughout this treatment the aggregated species are referred to as the Aurei. However, because the relationships of the Aurei to the remainder of Senecio are not yet fully understood, I believe it better to regard the Aurei as a convenient species-group, rather than as a formal taxonomic section.
Content strategy in LibGuides: An exploratory study
Abstract Since its inception in 2007, Springshare's LibGuides has become a popular content management system (CMS) with academic libraries. The challenges of managing LibGuides content through a cohesive content strategy have not been well documented. The researchers conducted a survey of academic libraries that were using the LibGuides platform in Fall 2019 to determine how institutions are managing content challenges. Of 120 respondents, only 53% of the respondents indicated that their institutions had content guidelines that LibGuides authors were expected to follow. The top three most observed elements of these content guidelines were page design (80%), content reuse policies (77%), naming conventions (73%), and navigation (3%). 15% of respondents' institutions did not review guides once they were published. Of those that reviewed guides post-publication, authors (84%) most frequently reviewed their own guides. These findings imply that LibGuides are largely cared for on an honour system. Guidelines tend towards quantifiable elements and omit more abstract concepts.