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Two species of Botrychium subgenus Botrychium (moonworts, Ophioglossaceae), Botrychium minganense Victorin and B. crenulatum W. H. Wagner, can sometimes be confused in the field, even by experts, because of their reduced morphology. Botrychium minganense can imitate B. crenulatum, which is more rare. They are afforded different degrees of protection on Federal lands, making the distinctness of these species a question of management, conservation, and systematic interest. The purpose of this study was to compare a morphometric analysis of these two species with an analysis of DNA markers from the same individuals, and to assess their distinctness under each method. Collections were made in Washington, Oregon, Idaho, and Montana from seven populations of B. crenulatum and 18 populations of B. minganense. Each plant was measured, emphasizing characters cited by authors in the original species descriptions. Canonical variate analysis performed on SAS separated the samples into two species groups with 32% overlap. RAPD genetic markers revealed more genetic variation than has previously been documented in moonworts. UPGMA cluster analysis of the similarity of RAPD profiles showed well-defined B. minganense and B. crenulatum clusters, but no distinct clusters within B. minganense that could be correlated with its morphological variability. Small samples of the moonwort species B. lunaria and B. simplex included for comparison also formed distinct clusters. Botrychium crenulatum had seven unique RAPD bands, and identification of B. crenulatum could be confirmed or ruled out with markers from one or two RAPD primers. Both B. crenulatum and B. lunaria have been suggested as possible diploid parents of tetraploid B. minganense. All RAPD markers absent in B. crenulatum but present in B. minganense were also present or polymorphic in B. lunaria, supporting B. lunaria as a possible parent. One very small population of B. minganense showed a monomorphic RAPD profile, consistent with inbreeding, but all other populations had multiple genotypes. Some plants of B. minganense clustered most closely with plants from populations up to 400 km away, suggesting that variation may be introduced into populations by occasional colonization by spores from distant sources.
Spores from single fronds of three different taxa of Pteridium aquilinum (L.) Kuhn were collected at different sites in Scotland, England and Sri Lanka. Gametophytes developed from these spores were treated to produce arrays of genetically identical clones. Sporophyte formation was determined when such clones from the same or different gametophytes, derived from the same frond, were combined in pairs in all possible ways to produce a diallel mating scheme. A recurring pattern of presence or absence of sporophyte formation indicated the occurrence of two genetic classes defined by no or very few sporophytes in pairs within either class but high frequency production in pair combinations of clones from different classes. The usual failure of sister clone pairs to produce a sporophyte contrasts with the frequently high incidence of sporophyte formation on the part of single, isolated non-cloned gametophytes. This conflict of evidence is discussed in relation to genetic incompatibility or, alternatively, the control of antheridia formation. The genetic differences revealed in cloned gametophytes provide an empirical way of determining whether a given stand of bracken is made up of more than one individual.
We report and describe a new population of the endangered Aleutian shield fern (Polystichum aleuticum C. Christens.) discovered on Mount Reed, Adak Island, Alaska. The new population is located at a lower elevation than the other known populations, placing the species' known elevational range between 338 m and 525 m. The discovery of this population is significant because it increases the total number of known populations and individuals for the species.