Premise The effective ex situ conservation of exceptional plants, whether in living collections or cryo‐collections, requires more resources than the conservation of other species. Because of their expertise with rare plants, botanical gardens are well positioned to lead this effort, but a well‐developed strategy requires a clear understanding of the resources needed. Methods Grant funding was obtained from the Institute of Museum and Library Services to support a three‐year project on cryobanking, and to provide smaller grants to 10 other botanical gardens for one‐year projects on either (1) seed behavior studies or (2) the development of protocols for in vitro propagation or cryopreservation. Results Nine of the partner gardens worked on 19 species (one was unable to continue due to the COVID‐19 pandemic), while the larger project focused on 14 species. A point system was developed for tasks accomplished, and the average costs per point of the larger and smaller projects were similar. Labor accounted for half the costs. Projects focused on species in the Asteraceae and Orchidaceae had lower costs per point than other species. Discussion Both large and small projects can contribute to a strategy for exceptional plant conservation for similar costs. Prioritizing species with lower costs could help advance the field while allowing time for work on more difficult species to develop.

Premise Reproducible seed propagation and production protocols were developed for Spiranthes and related taxa to facilitate ex situ conservation practices. Methods and Results Spiranthes seeds were scarified for 3‐ and 10‐min intervals in 10% sodium hypochlorite solution, then cultured on three seed germination media. After germination, seedlings were given one of the three photoperiod treatments, and then planted in one of four greenhouse substrates. Seed germination ranged from 0% to 90% and occurred on all three media only after the 3‐min scarification. Seedlings in the 24/0‐h light/dark and 16/8‐h light/dark photoperiods on P723 medium had significantly higher fresh weight than those in the dark treatment group. Ex vitro survival ranged from 55% to 95% across substrates. Conclusions Results show that Spiranthes seeds are damaged by extended chemical scarification, are adaptable to a variety of culture media, and require light for optimal development. Further experimentation showed that the propagation protocols described here can be applied broadly within the genus.

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Lilium pardalinum Kellogg is native to the Pacific Coast of the United States, and grows in woodland near streams. In the present study, the complete plastome of L. pardalinum was sequenced. The plastome sequence is 151,969 bp long with a large single copy, a small single copy, and two inverted repeat regions of length 81,401, 17,346, and 26,611 bp, respectively. A total of 133 genes were identified, including 82 coding genes, 8 ribosomal RNAs, 38 transfer RNAs, and 5 pseudogenes. Among the 5 pseudogenes, pseudo ndhF and ndhG genes were similar to that of L. washingtonianum and L. philadelphicum , respectively. Lilium pardalinum is sister to American lilies, except L. philadelphicum .

Phlox is an important genus of herbaceous ornamental plants previously targeted for germplasm development, characterization, and enhancement by the U.S. Department of Agriculture, National Plant Germplasm System. Among Phlox in cultivation, Phlox paniculata is the most widely grown and intensively bred species, but little is known about variation in genome size and ploidy of this species or of related taxa that may be used for germplasm enhancement. The objective of this study was to assess cytotype variation in a diverse collection of cultivars and wild germplasm of P. paniculata (subsection Paniculatae) and of related taxa in subsections Paniculatae and Phlox. The collection included 138 accessions from seven species and two interspecific hybrids. Flow cytometry was used to estimate holoploid (2C) genome sizes and to infer ploidy levels. Chromosome counts were made to calibrate ploidy with genome size for a subset of taxa. Most cultivars were diploid (2n = 2x = 14) and had mean genome sizes that did not vary between subsections Paniculatae (14.33 pg) and Phlox (14.23 pg) although size variation was greater among cultivars within subsection Phlox. Triploid cultivars of P. paniculata, with a mean genome size of 21.36 pg and mitotic chromosome counts of 2n = 3x = 21, were identified. Such triploids suggests previous interploid hybridization within this taxon. Five tetraploid (2n = 4x = 28) cultivars were found in subsection Phlox; all were selections of P. glaberrima ssp. triflora, and had a mean genome size of 25.44 pg; chromosome counts in one of these confirmed they were tetraploid. The putative hybrid Phlox Suffruticosa Group 'Miss Lingard' showed an intermediate genome size of 21.21 pg supporting a triploid, hybrid origin of this taxon. Mean 2C genome sizes among wild-collected accessions were similar to values reported for cultivars (Paniculatae = 14.59 pg, Phlox = 14.23 pg), but taxa in subsection Phlox exhibited greater variation that included two tetraploids identified among wild-collected accessions; one, of P. pulchra, had a mean genome size of 26.17 pg, representing the first report of polyploidy in the taxon. This is the first report on genome size for the majority of species in the study. Although genome size could not be used to differentiate taxa in subsections Paniculatae and Phlox, the data provide further insights into cytotype variation of Phlox germplasm useful for plant breeders and systematists.