Donald J. Padgett

A MONOGRAPH OF NUPHAR (NYMPHAEACEAE) 1

Abstract The genus Nuphar (Nymphaeaceae) is described to include 11 species native to fresh waters of the Northern Hemisphere. This assessment utilized morphometric analyses, cladistic analyses, evaluation of randomly amplified polymorphic DNA, and seed and pollen fertility estimations. Evolutionary reconstructions position the genus at the base of the family, most closely allied to Barclaya. Comprehensive cladistic analyses of morphological and molecular data have permitted a general phylogenetic interpretation of the genus. Two major evolutionary lineages are evident and recognized taxonomically at the section level. One (sect. Nuphar) includes N. lutea, N. × spenneriana, N. japonica, and N. × saijoensis, with an ultimate branch involving N. pumila and N. microphylla. The other lineage (sect. Astylus) includes N. polysepala, N. × rubrodisca, N. variegata, N. sagittifolia, and N. advena. All studies illustrate high morphological variability and close relationships of species within each section. The biology of Nuphar is summarized and a complete taxonomic treatment is presented.

Natural hybridization and the imperiled Nuphar of western Japan

Ponds in the Saijo Basin of western Japan contain three Nuphar taxa, two of which are threatened. It has been proposed previously that the rarest of the three, hitherto Nuphar japonica var. saijoensis, may have originated from natural hybridization between N. japonicaand Nuphar pumila subsp. oguraensis. To test this hypothesis, we conducted morphological analyses, pollen and seed fertility tests, and a RAPD analysis of all three pond-lilies. Individuals of the putative hybrid exhibit intermediate morphology, reduced pollen and seed viability, and genetic additivity in comparison to the other species. The putative hybrid is also limited geographically to an area of parental sympatry. Our findings support the hybrid origin of N. japonica var. saijoensis, which we recognize nomenclaturally as Nuphar × saijoensis. Loss and degradation of habitat due to urbanization is a major threat to the survival of this taxon.

Phenetic studies in Nuphar Sm. (Nymphaeaceae): Variation in sect. Nuphar

Abstract.Previous taxonomic assessments of the hydrophytic genus Nuphar Sm. (Nymphaeaceae) have inadequately considered the range of morphological variation existing in the genus. A comprehensive statistical analysis of morphological features among the recognized taxa of Nuphar is presented here, first using 10 fruit characters to delimit the separation of two infrageneric groups of taxa, and secondly using 31 characters to quantify the morphological variation found within sect. Nuphar. Results from combined phenetic analyses provided empirical support for recognition of two infrageneric groups of species in the genus (largely by fruit, stigmatic disk margin, neck, and stigmatic disk size) and for separation of taxa within sect. Nuphar (by leaf size, and fruit disk and neck size). Statistical analyses demonstrate that extensive variation in ranges of character states exists among sect. Nuphar taxa. However, a suite of qualitative and quantitative characters can be used to recognize five species and three subspecies within this predominantly Old World assemblage.

The Dietary Composition of Chrysemys picta picta (Eastern Painted Turtles) with Special Reference to the Seeds of Aquatic Macrophytes

Abstract Animals facilitate macrophyte seed dispersal in various ways despite specializations of macrophytes for water dispersal. Previous diet analyses of freshwater aquatic turtles revealed that several North American turtle species consume a variety and abundance of seeds among other plant material and animal prey. We quantified the dietary habits of Chrysemys picta picta (Eastern Painted Turtle) in a Massachusetts lake to examine if these animals included hydrophyte seeds in their diet and evaluate their capacity as passive seed-dispersal agents. Fifty-four turtles were trapped and housed to collect feces. Examination of feces revealed a diverse diet with comparatively high frequencies of animal, plant, and algal matter. Eight hundred fifty-seven seeds of at least nine plant species were egested (among 87% of turtles), with all but five (99%) seeds visibly intact. Seeds of Nuphar (473) and Decodon (305) were most abundant in the feces. Life-history characteristics of both C. p. picta and Nuphar suggest an effective endozoochorous seed dispersal association.

On the Introduction of Bolboschoenus glaucus (Cyperaceae) into Southern New Hampshire

River tuber-bulrush, Bolboschoenus fluviatilis (Torr.) Soják, was first reported as a novel addition to the flora of New Hampshire by Padgett and Crow (1993). Although this species is native to surrounding New England states, this population was the result of an intentional introduction as part of a created wetland planting-scheme. Thousands of tubers were reportedly imported from a Wisconsin supplier in 1990 and planted when the marsh was constructed. While researching Bolboschoenus for the Flora of North America treatment, S.G.S. borrowed some Bolboschoenus collections made from the New Hampshire site. Upon examination, specimens initially identified as B. maritimus (L.) Palla (Padgett 256 and 366) were found instead to be B. glaucus (Lam.) S.G. Smith, the Glaucous tuber-bulrush or Alkali bulrush. These specimens of B. glaucus, a species native to Eurasia, document the first occurrence of the taxon in New England. In 2014, the voucher specimen documenting the B. fluviatilis discovery (Padgett 354) was examined and its correct determination confirmed. Widespread in the Old World, Bolboschoenus glaucus has been introduced into California, Idaho, New York, and Oregon, perhaps as a by-product of rice culture. It has been promoted—along with B. fluviatilis—as a good waterfowl food (George 1963) in California, a state representing one of the earliest documented introductions of the species into North America (Smith 2003). Bolboschoenus glaucus has been confused with B. maritimus worldwide and the two [the latter as B. maritimus subsp. paludosus (A. Nelson) T. Koyama] are known to hybridize in California rice fields where both are cultivated as waterfowl food.

SEED PRODUCTION AND GERMINATION IN LONG'S BITTERCRESS (CARDAMINE LONGII) OF MASSACHUSETTS

Abstract Cardamine longii (Brassicaceae), longs bittercress, is an imperiled plant confined largely to freshwater tidal marshes of the eastern U.S. To better understand possible causes of rarity in the species, its reproductive output was studied in two southeastern Massachusetts populations. Plants were found to produce about 10 fruits per individual (five per inflorescence), with the majority of a population fruiting in July. About 78% of the flowers produced in the two populations set fruit, with each fruit yielding nine seeds on average. Seeds were viable as indicated by their ability to germinate in the laboratory. Without any prior cold treatment, germination levels reached 87% over a four-week period yet were markedly reduced when seeds were allowed to dry prior to incubation. We suggest that fruit and seed production and viability are not important factors in limiting C. longiis population sizes and growth.