Phenology, Population Dynamics, and Flowering Dynamics of Case's Ladies'-tresses, <em>Spiranthes casei</em> var. <em>casei</em> (Orchidaceae), in Ottawa, Ontario

Abstract

We describe a seven-year study (2002–2008) of a population of Case’s Ladies’-tresses (Spiranthes casei var. casei) in the western Greenbelt in Ottawa, Ontario, that had been extant since at least 1972. We also record a temporary colonization in the eastern Greenbelt for 11 years (1998–2008). The seven life history stages identified were seed, juvenile, immature, flowering, vegetative, offshoot (ramet), and non-emergent. Mature plants present in the first two years of the study had mean half lives of 9.4 years. Flowering and seed production were limited by damp, cloudy weather when fall rosettes develop, by gastropod herbivory in early summer, by drought in mid-summer, and by deer herbivory in late summer. Given the resulting wide fluctuations in the fractions of plants flowering, as well as the lack of visibility of vegetative plants, this study demonstrates the limitations of annual censuses of flowering stems for determining the actual sizes of populations and for detecting long-term population trends.

Asymbiotic in vitro seed germination, in vitro seedling development, and ex vitro acclimatization of Spiranthes

“…Although significant advances made with certain genera, such as Cypripedium L., have resulted in successful large‐scale horticultural production and in situ/ex situ conservation efforts, information related to many genera, including Spiranthes Rich., is scattered or remains unpublished (Steele, 1996 ; Seaton et al, 2013 ). Like other orchids, Spiranthes species can be considered “exceptional” (i.e., they cannot be conserved long‐term using conventional seed banking methods or require special handling and conditions for germination) due to the laboratory requirements for propagation of the dust‐like seeds, unknown seed desiccation tolerance and lifespan, and variable natural seed production in some species resulting from a variety of factors (Reddoch and Reddoch, 2009 ; Pence et al, 2022 ). Therefore, studies that result in baseline, reproducible propagation protocols for Spiranthes would be of use to horticulturists, conservationists, restoration biologists, seed scientists, citizen scientists, and others interested in applied orchid and exceptional species conservation.…”

Orchid weevils (Coleoptera: Curculionidae) in Canada

“…Adult S. ovata have been found on Cypripedioideae ( Cypripedium acaule Aiton, Cypripedium arietinum Brown, Cypripedium candidum Muhlenberg ex Willdenow, and Cypripedium parviflorum var. pubescens ), Epidendroideae ( Corallorhiza striata Lindley, Corallorhiza trifida Châtel, Epipactis helleborine (Linnaeus) Crantz), and Orchidoideae ( Amerorchis rotundifolia (Banks ex Pursh) Hultén, Galearis spectabilis (Linnaeus) Rafinesque, Platanthera aquilonis , P. leucophaea (Nuttall) Lindley, P. psycodes (Linnaeus) Gray, Spiranthes casei Catling and Cruise) (Harrington 1884; Brown 1966; Judd 1979; Howden 1995; Reddoch and Reddoch 1997, 2009; Dunford et al . 2006; Light and MacConaill 2011; Prena and O’Brien 2011; Walsh et al .…”

“…They represent the most northern populations of orchid weevils anywhere in the world. Two of them attracted repeatedly the attention of botanists and ecologists during their studies of North American orchids, with Stethobaris ovata (LeConte, 1869) so far having caused the greatest concern in Canada (Brown 1966; Reddoch and Reddoch 1997, 2009; Light and MacConaill 2011). Not treated herein (but included in the key) are two unestablished exotic species of the same subfamily, which have been found sporadically on imported orchid cultivars in British Columbia, Nova Scotia, and Ontario, Canada before 1990 (McNamara 1991; Majka et al .…”