Silene is a large genus of flowering plants in the family Caryophyllaceae, consisting of approximately 850 species of annual to perennial herbs commonly known as campions or catchflies.[1][2][3] These plants are typically erect, arising from a caudex, taproot, or rhizome, and are rarely dioecious, with simple, opposite leaves that are linear to oblanceolate and one-veined.[1] Their flowers are generally bisexual, featuring five fused sepals forming a tube (4–38 mm long) and five petals (6–62 mm), along with three to five styles; the fruit is a capsule containing many gray to black seeds.[1]Native to regions across North America, South America, Eurasia, and Africa, with a concentration in the Northern Hemisphere, Silene species have been introduced worldwide and often thrive in disturbed habitats.[1][4] Many exhibit sticky glandular hairs on stems and calyces, which give rise to the "catchfly" common name by trapping small insects, though this serves more as a defensive mechanism than for pollination.[3] Ecologically, the genus includes both native wildflowers that support pollinators and invasive weeds that can outcompete local flora in disturbed areas, such as roadsides and agricultural fields.[5] Several species hold conservation significance, with some listed as rare or endangered due to habitat loss.[6]The name Silene derives from the Greek mythological figure Silenus, possibly alluding to the swollen calyces of some species resembling his bloated form, and the genus has been taxonomically challenging due to its morphological diversity and extensive hybridization.[1]
Description
Morphology
Silene species exhibit a range of habits, primarily as annual, biennial, or perennial herbs, rarely forming subshrubs or suffrutescent growths; they often appear decumbent at the base or cespitose.[7][8] Stems are typically erect or ascending, simple or branched, terete or angular, and frequently glandular-pubescent or viscid, with heights varying from 5 cm in dwarf species to over 1 m in tall perennials.[7][8] Root systems differ by life cycle: annuals generally possess fibrous roots, while perennials develop taproots that are slender or stout and deep, often with a branched caudex; some species are stoloniferous or rhizomatous.[7][8] Leaves are opposite, occasionally whorled, simple, and entire, connate proximally; basal leaves are petiolate and cauline leaves sessile, with blades that are 1–5-veined, linear to ovate or lanceolate, and 1–10 cm long, featuring acute to obtuse apices.[7][8]Reproductive structures are borne in inflorescences that are terminal or axillary cymose panicles, often dichasial cymes, or solitary flowers, typically glandular-pubescent and viscid.[7][8] The calyx is tubular to campanulate or inflated, 10–30-veined, (4–)10–28(–40) mm long, 5-toothed, and often persistent in fruit.[7][8] Flowers are typically bisexual, but unisexual in the dioecious and gynodioecious species that occur in several sections of the genus, with 5 petals that are clawed, white, pink, scarlet, or purple, and deeply bifid or dissected at the limb apex; in dioecious species, minor sexual dimorphism may occur in floral structures.[7][8] The androecium consists of 10 dimorphic stamens arising with the petals, while the gynoecium features an ovoid to globose ovary that is 1- or 3–5-locular, with 3–5 glabrous styles 1.5–20 mm long.[7][8]The fruit is a capsule, ovoid to globose, dehiscing by 3–5 valves into 6–10 teeth, often with a present carpophore; it contains (5–)15–100(–500+) reniform, tuberculate or papillate seeds that are reddish to black.[7][8]
Reproduction
Silene species primarily reproduce sexually through seed production, though asexual reproduction occurs rarely in certain perennials via vegetative propagation from rhizomes. For instance, Silene nivea forms long rhizomes that allow clonal spread, enabling the plant to colonize new areas without seed dispersal.[9] Similarly, Silene vulgaris and Silene chalcedonica produce rhizomes that facilitate vegetative reproduction alongside seed-based propagation.[10][11] Many species exhibit self-incompatibility, promoting outcrossing and influencing seed set in hermaphroditic populations.[12] Apomixis, or asexual seed formation, remains undocumented in the genus.Seed production in Silene involves the development of dry capsules that dehisce at maturity to release numerous small seeds, typically measuring 0.4–1.9 mm in length.[4] These capsules, often with six teeth, open via hygroscopic movements triggered by drying, allowing seeds to be shed gradually.[13] Dispersal occurs primarily through gravity, with seeds falling near the parent plant, augmented by wind shaking the stems or capsules in species like Silene latifolia.[14][15] In some cases, limited animal-mediated dispersal may occur when seeds adhere briefly to fur or are dislodged by passing animals.[9]Germination in Silene varies by species and environmental conditions, with many exhibiting physiological dormancy broken by cold stratification. For example, seeds of Silene elisabethae show improved germination with increasing durations of cold stratification, reaching up to 90%.[16] Some species, such as Silene acaulis, show light-dependent germination, where exposure to light post-stratification enhances seedling establishment.[17] Without stratification, germination percentages remain low, typically below 40% even under optimal temperatures.[18]Life cycle variations among Silene species include annuals that complete their cycle in one growing season, biennials that overwinter as rosettes before flowering, and perennials that persist for multiple years. Annuals like Silene antirrhina germinate, flower, and set seed rapidly in favorable conditions.[19] Biennials and short-lived perennials, such as Silene latifolia, form basal rosettes in the first year, bolting and reproducing in the second. Perennials maintain rosettes or clumps across seasons, supporting repeated seed production.[20]Fertility rates in Silene differ based on sexual systems, with hermaphroditic individuals generally achieving high seed set through self- or cross-pollination, often exceeding 80 seeds per capsule in optimal conditions.[21] In dioecious species like Silene dioica and Silene latifolia, seed set in females is typically reduced due to spatial separation of sexes, leading to pollen limitation over distances greater than a few meters.[22][23] This reduction can lower overall fertility by 20–50% in isolated populations compared to hermaphroditic counterparts.[24]
Taxonomy
History
The genus Silene was formally established by Carl Linnaeus in his seminal 1753 publication Species Plantarum, where he described 27 species based on morphological characteristics such as flower structure and calyx features.[25] This initial description laid the foundation for the genus within the Caryophyllaceae family, drawing on earlier herbal traditions but introducing binomial nomenclature for clarity in botanical classification. Linnaeus's work emphasized the variability in seed capsules and petals, grouping species primarily from European and Mediterranean regions.Early 19th-century contributions expanded the genus significantly. In 1824, Daniel Otth, in de Candolle's Prodromus Systematis Naturalis Regni Vegetabilis, classified 217 Silene species into eight sections, relying on traits like inflorescence type and leaf arrangement to organize the growing diversity.[25] The genusMelandrium, proposed by Elias Fries in 1828 for dioecious species previously under Lychnis and Silene, represented a key segregation effort, highlighting sexual dimorphism as a distinguishing factor; it was later merged back into Silene as classifications evolved. Paul Rohrbach's 1868 monograph Monographie der Gattung Silene provided the first comprehensive systematic treatment, detailing over 300 species and emphasizing aestivation patterns and capsule morphology, though it retained some artificial groupings.[26]Charles Darwin contributed to early understandings of Silene biology in the 1860s, examining dimorphism and reproductive strategies in species like Silene (then classified under Lychnis), noting failures in self-fertilization and the adaptive value of dioecy derived from hermaphroditism.[27] Pre-molecular era taxonomy faced challenges from artificial classifications based on geographic distribution or growth habit, leading to an proliferation of names—over 2,000 species described by 1900—many of which proved synonymous upon closer scrutiny. In the early 20th century, Silene emerged as a model for inheritance studies, with researchers like Hugo de Vries and others applying Mendelian principles to explore sex-linked traits and cytoplasmic effects in species such as S. latifolia.[27] These efforts, building on Rohrbach's framework, underscored the genus's utility in investigating genetic variability before molecular tools revolutionized phylogeny.
Etymology
The genus name Silene originates from the Latin feminine form of Silenus, the Greek woodland deity and foster father of Dionysus (Bacchus), who was often portrayed as intoxicated and covered in foam or froth, an allusion to the sticky, viscid exudates produced by the stems and calyces of many species in the genus.[7][1][28] An alternative etymology proposes derivation from the Greek sialon, meaning "saliva" or "spittle," in reference to the glandular secretions that give some species a foamy or sticky appearance.Common names for plants in the genus include "campion," derived from the Latin campio (champion), reflecting the showy, prominent flowers that were historically used in Europe to crown victors in sporting events or battles.[3] Another widespread name is "catchfly," stemming from the viscid, glandular stems that can trap or "catch" small insects attempting to crawl over them.[29][3]Within the genus, sectional names often draw from morphological traits using Greek or Latin roots; for example, the type section Silene is named directly after the genus, while sect. Conoimorpha refers to species characterized by cone-shaped or inflated calyces, combining Greek kōnos (cone) and morphē (form).[30]Nomenclatural changes have included the merger of the former genus Lychnis (from Greek lychnos, meaning "lamp," alluding to flame-like flowers or the use of woolly leaves as lamp wicks) into Silene, driven by shared morphological and phylogenetic traits rather than etymological considerations, resulting in numerous species transfers such as Silene coronaria (formerly Lychnis coronaria).[7][31]
Classification
Silene belongs to the family Caryophyllaceae, within the subfamily Silenoideae, characterized by flowers with united petals and absence of stipules.[32] The closest relatives to Silene within this subfamily include the genus Atocion, often treated as congeneric or closely allied based on shared morphological and molecular traits, and Dianthus, which shares a broader tribal affinity in the Sileneae. These relationships have been clarified through phylogenetic analyses emphasizing nuclear and plastid DNA markers.[33]Infrageneric classification of Silene recognizes three main subgenera—Behenantha (Otth.) Torr. & A. Gray, Lychnis (L.) Greuter, and Silene—supported by comprehensive molecular phylogenies spanning 2003 to 2020 that integrate multi-locus data such as ITS, trnL-F, and ETS sequences.[25] These subgenera encompass approximately 35 sections, with examples including sect. Silene (characterized by annual habits and inflated calyces) and sect. Psammophila (featuring psammophilous adaptations in sandy habitats), reflecting monophyletic groups defined by floral, fruit, and ecological traits corroborated by Bayesian and maximum likelihood analyses.[25] This framework resolves many historical ambiguities in sectional boundaries, though ongoing refinements continue based on expanded sampling.[34]The genus comprises about 908 accepted species according to the 2023 update of Plants of the World Online, though species delimitation remains challenging due to frequent hybridization events and polyploidy, which blur morphological boundaries and complicate phylogenetic resolution in complexes like sect. Physolychnis.[35][36] Hybrid zones often produce intermediate forms that evade clear taxonomic assignment, while allopolyploid origins—evident in taxa up to 10-ploid—further confound diploid-polyploid species clusters, necessitating integrative approaches combining genomics and ecology for accurate circumscription.[37]Recent taxonomic revisions include the merger of the former genus Melandrium Röhl.—encompassing dioecious species like S. latifolia—into Silene during the 2010s, driven by phylogenetic evidence placing it within sect. Melandrium based on chloroplast and nuclear markers that rejected its generic distinctness.[38] Additionally, a 2020 study formally described sect. Arenosae as a new infrageneric unit, confirming nine annual species primarily from the eastern Mediterranean to southwestern Asia, distinguished by dehiscent capsules and psammophilous distributions, with delimitation supported by RAD-seq and morphological revisions.[39]
Sexual Systems
The genus Silene displays remarkable diversity in sexual systems, reflecting its evolutionary lability and serving as a key feature in taxonomic and phylogenetic studies. Hermaphroditism predominates, occurring in approximately 58% of species, while dioecy and gynodioecy each account for about 14% and 13%, respectively, based on an extensive survey of 98 species across subgenera Silene and Behenantha. These proportions highlight hermaphroditism as the ancestral state, with transitions to separate-sex systems occurring independently multiple times within the genus.[40]Dioecy in Silene is primarily confined to specific lineages, such as section Melandrium (including model species like S. latifolia and S. dioica), where sex determination is governed by heteromorphic X and Y chromosomes. The Y chromosome harbors male-determining genes that suppress female function and promote male traits, leading to distinct sexual dimorphism; for instance, males typically exhibit larger flowers and higher floral display compared to females, traits partially linked to sex chromosomes. These genetic mechanisms facilitate the evolution of dioecy from gynodioecious ancestors, with the Y chromosome showing degeneration over time due to suppressed recombination.[41][42]Gynodioecy, characterized by co-occurring female and hermaphroditic individuals, is maintained through interactions between cytoplasmic male sterility (CMS) factors in the mitochondria and nuclear restorer genes that counteract sterility. In species like S. nutans and S. vulgaris, multiple CMS mitotypes exist, with nuclear restorers exhibiting epistatic interactions that allow variable female frequencies across populations, often ranging from 10% to 50% depending on environmental and genetic contexts. This nuclear-cytoplasmic conflict underpins the stability of gynodioecy, enabling females to persist via seed fertility advantages despite pollen production limitations in hermaphrodites.[43][44]Less common systems include trioecy, where females, males, and hermaphrodites coexist, as observed in certain populations of S. acaulis, potentially representing transitional states toward dioecy. Andromonoecy, featuring plants with both staminate and hermaphroditic flowers, is rare but documented in some Asian species, such as those in Chinese lineages, contributing to mating system variation. Overall, evolutionary transitions among these systems are frequent and labile, with molecular phylogenies revealing at least three independent origins of dioecy from hermaphroditic or gynodioecious progenitors, driven by genetic conflicts and selection pressures.[45][46][47]
Distribution and Habitat
Geographic Range
The genus Silene is primarily native to the Northern Hemisphere, with its core range encompassing temperate and Mediterranean regions of Eurasia, where the majority of its approximately 700–900 species are found.[48] This area hosts the highest diversity, estimated at around 500 species, reflecting the genus's evolutionary origins in the mid-late Miocene within the Mediterranean Basin.[49] The distribution extends eastward to the mountains of tropical Asia, southward to North Africa and parts of South America, as well as westward to North America, where about 70 species occur, many of them polyploid endemics.[7][1] Scattered populations also inhabit high-elevation habitats in tropical African mountains, underscoring the genus's preference for cooler, temperate-like conditions even in subtropical zones.[34]Key centers of endemism for Silene include the Mediterranean Basin, particularly in Turkey and Greece, where nearly half of regional species are unique, including members of section Sclerocalycinae.[50] The Caucasus region and the Iranian Plateau, especially northwestern Iran, represent additional hotspots, harboring high species richness and narrow endemics adapted to alpine and rocky terrains.[51] These areas contribute significantly to the genus's overall variation, with biogeographic patterns dominated by Holarctic distributions and disjunct occurrences between Eurasia and North America, likely facilitated by ancient migrations across the Bering land bridge during glacial periods.[52]Several Silene species have been introduced outside their native ranges, notably S. vulgaris and S. latifolia, which arrived in North America in the late 18th to early 19th centuries via ship ballast or contaminated seeds and have since become invasive in disturbed habitats across the continent.[13] Similarly, both species were introduced to Australia in the 19th century as ornamental or fodder plants and now exhibit invasive tendencies in temperate grasslands and roadsides.[53] A 2019 European study found significant phenotypic plasticity in S. vulgaris populations, enabling compensatory adaptations such as reduced flower number under warmer and drier conditions, suggesting potential resilience to climate change.[54]
Habitat Preferences
Species in the genus Silene exhibit a wide range of habitat preferences, primarily favoring well-drained substrates such as sands, rocks, and chalk, with many showing a strong affinity for calcareous soils. For instance, Silene nutans thrives on limestone outcrops and steep grassy slopes, particularly in regions like the Peak District where such substrates predominate. Similarly, Silene vulgaris prefers moderately fertile, open, calcareous, sandy, or gravelly conditions with some humus content, reflecting the genus's general adaptation to neutral to basic pH environments. These preferences enable Silene species to colonize rocky slopes and open grasslands, where soil texture is often sandy and slightly alkaline.[55][56][57]Climatically, Silene occupies temperate to alpine zones, with notable drought tolerance in Mediterranean habitats and cold hardiness in boreal and arctic regions. In Mediterranean climates, species like Silene gallica endure dry, non-saline conditions such as meadows and wastelands, supported by adaptations to hot, dry summers and mild, wet winters. Boreal representatives, including Silene dioica, persist in moister, cooler settings up to 500 m elevation, while arctic-alpine species such as Silene acaulis withstand temperatures down to -40°C in tundra environments. Altitude ranges broadly from sea level in coastal and lowland areas to 5000 m in high-elevation alpine meadows, as seen in Silene himalayensis across the Himalayas. Moisture levels vary from xeric in open, dry grasslands—where glandular hairs on species like Silene scouleri aid in protection—to mesic in riparian zones, exemplified by Silene dioica in rich meadows and streamside habitats.[58][59][3][60][61][62][63]Many Silene species act as pioneers in disturbed habitats, readily establishing on roadsides, waste grounds, and other anthropogenic sites with loose, well-aerated soils. This is evident in Silene vulgaris, which frequently appears in such areas alongside natural settings like alluvial woodlands for Silene nivea. While global distribution spans the Northern Hemisphere with hotspots around the Mediterranean, these abiotic preferences underpin the genus's versatility across diverse landscapes.[64][65][66]
Ecology
Pollination
The genus Silene displays a range of pollination strategies, with many species relying on insect vectors that exploit floral scents, nectar, and pollen rewards. Nocturnal moths, particularly from the genus Hadena (Noctuidae), serve as primary pollinators for numerous Silenespecies, often functioning as nursery pollinators that both transfer pollen and oviposit in flowers or developing fruits.[67] These moths are attracted to the nocturnal fragrance emitted by flowers, which peaks in the evening to align with their activity patterns.[68] Diurnal species or those with mixed regimes are frequently visited by bees (e.g., bumblebees like Bombus fervidus in S. spaldingii) and flies (including syrphids and tachinids), which collect pollen and nectar.[69][70]Floral traits in Silene are adapted to facilitate effective pollination while deterring inefficient visitors. Flowers are typically nectar-producing with hexose-rich rewards that vary by time of day, sex phase, and age, though pollen is abundant and serves as a key resource for many visitors.[71] The corolla often forms a tube that accommodates moth proboscides or bee mouthparts, and many species emit scents from osmophores to lure pollinators.[72] Viscid glandular stems and calyces trap small crawling insects, reducing nectar or pollen theft by non-pollinating arthropods and favoring larger flying visitors.[73][74]Selfing rates in hermaphroditic Silenespecies vary widely, often reaching moderate to high levels (e.g., up to 41% in S. acutifolia), facilitated by the absence of strong self-incompatibility and opportunities for geitonogamy or facilitated self-pollination. Despite this, outcrossing is promoted by temporal protandry, where anthers dehisce before stigmas become receptive, minimizing autogamy within flowers.[75] This dichogamy, combined with spatial separation in some dioecious taxa, enhances pollen flow between plants.[76]Pollinator specialization differs across Silene sections. In section Silene, species tend toward generalist pollination, attracting a broad array of diurnal and nocturnal insects without strict syndromes.[77] For instance, S. otites features long-tubed flowers suited to hawkmoths and other crepuscular/nocturnal Lepidoptera, though it also receives visits from diurnal flies and bees, indicating partial specialization.[78][79]
Biotic Interactions
Silene species engage in a range of biotic interactions beyond pollination, including antagonistic relationships with herbivores and pathogens as well as mutualistic associations that influence plant fitness and distribution. Specialized herbivores, such as the noctuid moth Hadena bicruris, target reproductive structures by ovipositing eggs directly on the ovaries of host plants like Silene latifolia. Upon hatching, the larvae consume developing seeds, effectively manipulating seed set and reducing host reproductive output, though females preferentially avoid oviposition on pathogen-infected flowers to ensure larval survival.[80] Other folivores, including aphids such as Brachycaudus lychnidis, feed on leaves and stems, inducing sex-specific changes in floral volatiles that alter interactions with other insects.[81] These herbivory pressures can vary with plant population density, with higher damage observed in larger, less isolated stands.[82]Pathogenic interactions further constrain Silene populations, particularly through fungal and viral agents that impair growth and reproduction. Rust fungi in the genus Uromyces, such as U. silenes-chloraefoliae on Silene chlorifolia, infect leaves and stems, producing pustules that disrupt photosynthesis and vascular function, though direct links to sterility are more commonly associated with related pathogens like the anther-smut fungus Microbotryum silenes-dioicae, which sterilizes infected plants by replacing pollen with spores.[83][84] Viral infections, including potexviruses like Silene virus X (SVX) on Silene pratensis and turnip vein-clearing virus on Silene flos-cuculi, cause mosaic symptoms and stunting in wild populations, with prevalence potentially elevated in dense stands due to increased transmission efficiency.[85][86] These pathogens exploit high host densities, contributing to episodic outbreaks that reduce population viability.[87]Mutualistic relationships provide compensatory benefits, notably through mycorrhizal associations that enhance nutrient uptake in challenging environments. Many Silene species form arbuscular mycorrhizal symbioses, albeit sometimes weakly, with fungi improving phosphorus acquisition in nutrient-poor soils and boosting overall growth, though this can inadvertently facilitate pathogen infection rates.[88][89] In glandular species, viscid trichomes on stems and leaves act as passive traps for small insects, potentially benefiting plantdefense by immobilizing herbivores and providing resources for predatory arthropods, thereby enhancing indirect protection.[90][91]Invasive dynamics exemplify how altered biotic interactions drive ecological impacts, as seen with Silene latifolia in North America. Introduced populations outcompete native flora partly by escaping specialist enemies from their native range while co-opting novel mutualists and antagonists, such as the native seed predator Hadena ectypa, which pollinates but also consumes seeds, potentially favoring invasive genotypes through relaxed predation pressure.[92] Recent studies highlight how these shifted interactions, including changes in volatile emissions under herbivory, contribute to invasion success by disrupting native community structures.[93] Such patterns underscore the role of biotic novelty in facilitating range expansion.[94]
Species Diversity
Number and Variation
The genus Silene encompasses approximately 908 accepted species worldwide, according to the 2025 assessment by Plants of the World Online (POWO), though estimates vary between 700 and over 1,000 due to the prevalence of cryptic species that are difficult to distinguish morphologically and genetically.[35][4] This variation stems from ongoing taxonomic revisions, where molecular data often reveal hidden diversity within apparent morphospecies. Between 2020 and 2025, phylogenetic and ecological studies have led to the description of at least 20 new species, primarily through species delimitation in understudied regions, including Silene isabellae from Albania in 2023 and Silene vanchingshanensis from China in 2022.[95][96][39][95]Morphological diversity in Silene is extensive, with plants ranging from prostrate alpine forms as short as 5 cm, such as cushion-like S. acaulis, to tall biennials reaching 1.5 m, like S. ovata.[97][98] Key identification features include variation in calyx shape and dentition, where teeth are often heteromorphic, with three differing from the other two, aiding in sectional classification.[39] At the genetic level, the genus exhibits high polyploidy, with chromosome numbers ranging from diploid 2n=24 (the most common) to higher ploidy levels up to 2n=120 in decaploid forms, contributing to adaptive radiation.[99][100] Hybridization is frequent in contact zones between closely related species, such as S. latifolia and S. dioica, leading to introgression and further complicating species boundaries.[101]Species richness is highest in Eurasia, with over 600 species concentrated in temperate and montane habitats, compared to about 150 in the Americas (including roughly 70 in North America) and around 100 in Africa.[7][4] Taxonomic challenges persist due to undersampling in Asian biodiversity hotspots, where remote montane areas remain poorly explored, potentially harboring additional cryptic taxa.[39] Additionally, climate change is accelerating speciation in mountain ranges by promoting isolation and adaptation in fragmented habitats, as evidenced by shifting distributions and novel genetic variants in alpine Silene populations.[102]
Notable Species
Silene latifolia, commonly known as white campion, is a dioecious species native to Europe but invasive in North America, where it has spread widely in disturbed habitats such as roadsides and fields. It serves as a key model organism in studies of sex chromosomeevolution due to its XY sex determination system, which has been extensively researched for insights into genetic mechanisms of sex differentiation.Silene vulgaris, also called bladder campion, is a widespread weed originating from Europe and Asia, now naturalized globally, including in North America, where it thrives in agricultural fields and waste areas. The plant is notable for its edible young leaves used in traditional cuisines, particularly in Mediterranean regions, and it possesses a diploid chromosome number of 2n=24, facilitating genetic studies on hybridization and polyploidy.Silene acaulis, known as moss campion, is a low-growing perennial adapted to arctic and alpine environments across the Northern Hemisphere, forming dense cushion-like mats that protect against harsh winds and cold. This species acts as an indicator of climate change impacts, with populations showing shifts in flowering times and distribution in response to warming temperatures in polar regions.Silene undulata, referred to as the African dream root, is indigenous to the Eastern Cape of South Africa and holds cultural significance among the Xhosa people, who use its tuberous roots in rituals to induce vivid, lucid dreams for divination and spiritual purposes. The plant's roots contain triterpenesaponins believed to influence sleep patterns, though scientific validation of these effects remains limited.Silene alexandri is an endangered endemic species found only on the island of Molokai in Hawaii, growing to heights of 30-60 cm in montane wet forests. It faces severe threats from non-native feral goats that degrade its habitat through browsing and soil erosion, contributing to its critically endangered status.[103]
Human Uses
Ornamental Cultivation
Silene species are valued in ornamental horticulture for their vibrant flowers and versatile growth habits, making them suitable for borders, rock gardens, and containers. Popular cultivars include Silene armeria, commonly known as none-so-pretty or sweet William catchfly, which forms compact mounds ideal for garden borders and cottage-style plantings with its clusters of bright pink to magenta blooms on 16- to 20-inch stems.[104][105] Similarly, Silene pendula, or nodding catchfly, is favored for its trailing habit, cascading gracefully in rock gardens, hanging baskets, or as a groundcover with nodding pink flowers.[106][107]Propagation of Silene is straightforward, primarily through seeds sown directly in the garden in spring after the last frost or in fall for natural stratification, or started indoors 6 to 8 weeks prior under cool conditions of 60-70°F to ensure even germination.[108][109]Perennial species can also be divided in early spring or fall, with success depending on well-drained soil to minimize rot.[110]Optimal growing conditions for most ornamental Silene include full sun to partial shade and moderately fertile, well-drained soils with neutral to slightly acidic pH, as poor drainage can lead to root issues.[111][29] They are generally hardy in USDA zones 3 to 9, tolerating drought once established but benefiting from consistent moisture during dry spells.[112]Several Silene species have been cultivated in European gardens since at least the 17th century, with modern breeding producing hybrids like 'Sibella Carmine' for enhanced color range in shades of pink and white.[113][114]Challenges in cultivation include susceptibility to slugs and aphids, particularly in damp conditions, which can damage foliage and flowers; cultural controls like reducing mulch and evening watering help mitigate this.[108] Recent trends toward native plant gardening, prominent in 2023, have increased interest in indigenous Silene species for sustainable landscapes, promoting biodiversity in ornamental settings.[115][116]
Culinary and Medicinal Applications
Silene vulgaris, commonly known as bladder campion, has been traditionally utilized in Mediterranean cuisine, where its young leaves are boiled and served as a spinach substitute, often incorporated into Greek horta—a dish of wild greens seasoned with olive oil and lemon. This preparation method preserves the plant's nutritional profile, including its high vitamin C content, which contributes to its antiscorbutic properties and supports immune health when consumed regularly. Recent analyses of wild edible greens confirm that S. vulgaris retains significant ascorbic acid levels even after cooking, making it a valuable source of this essential nutrient in traditional diets.In medicinal contexts, Silene undulata roots are employed by the Xhosa people of South Africa as ubulawu, a traditional preparation consumed to induce vivid and lucid dreams for spiritual communication with ancestors, attributed to the presence of triterpenoid saponins that act as acetylcholinesterase inhibitors. Various Silenespecies, including those used in Asian folk medicine, serve as emollients applied topically to soothe wounds, cleanse skin, and promote healing through baths or direct washes. For instance, in Iranian traditional practices, S. conoidea seeds are utilized as a diuretic to alleviate urinary issues and reduce fluid retention.Modern pharmacological research has validated some of these applications, suggesting potential for treating inflammatory conditions. Preparations typically involve infusions for internal use, such as brewing roots into teas for dream induction, or poultices made from crushed leaves and stems applied externally for wound care. However, caution is advised due to the hemolytic properties of saponins in many Silene species, which can cause gastrointestinal upset or toxicity if consumed in excess, particularly in raw forms.Ethnobotanical surveys conducted in 2024 have expanded documentation of Silene uses, emphasizing its role in sustainable foraging practices amid urbanization, with S. vulgaris noted as a commonly gathered species in peri-urban areas for both nutritional and therapeutic purposes.
Evolutionary History
Fossil Record
The earliest known fossils attributable to the genus Silene consist of seeds of S. microsperma Mai recovered from the Oberleichtersbach Formation in the Rhön Mountains of central Germany, dating to the Chattian stage of the Late Oligocene (approximately 26–23 million years ago). These small seeds, measuring about 0.5–0.7 mm in length, exhibit a reniform shape and finely reticulate surface ornamentation closely resembling those of extant small-seeded Silene species, suggesting morphological conservatism within the genus over this period. The fossils were preserved in blue-black clayey sediments within a doline (sinkhole) deposit, indicative of an open, mesophytic forest environment.[117]Additional fossil evidence includes dispersed pollen grains of Caryophyllaceae, to which Silene belongs, from Miocene sediments (23–5 million years ago) across Europe and Asia. In Europe, such pollen first appears in the Early Miocene, often as psilate or faintly ornamented tricolpate grains typical of the family, recorded in various lacustrine and fluvial deposits. In Asia, comparable pollen has been identified in the Middle Miocene Shanwang flora of Shandong Province, China, where it represents a minor component of diverse palynofloras from subtropical mixed forests.[118][119]The fossil record of Silene and related Caryophyllaceae is notably sparse, primarily due to the predominantly herbaceous growth habit of the group, which favors rapid decay over mineralization or compression preservation in most depositional environments. The fossil record of Silene and related Caryophyllaceae remains sparse, with only a handful of formally described taxa, mostly as seeds, fruits, or pollen, with macrofossils being particularly rare outside of exceptional lagerstätten.[118]
Phylogenetic Insights
Phylogenetic analyses of the genus Silene have revealed a complex evolutionary history, with major clades organized into three subgenera: S. subg. Behenantha (encompassing 18 sections), S. subg. Lychnis (divided into three main clades), and S. subg. Silene (including 11 sections). A comprehensive 2020 multi-locus phylogeny, based on nuclear ribosomal DNA ITS sequences from 415 species and chloroplast DNArps16intron from 397 species, resolved relationships for approximately 80% of the 33 recognized sections, highlighting monophyletic groups that differ from traditional morphology-based classifications. However, basal nodes among subgenera remain poorly supported, with S. subg. Lychnis weakly positioned as sister to the others and limited resolution within S. subg. Behenantha.[120]The genus exhibits a pattern of early divergence primarily in Eurasian lineages, from which multiple independent dispersals led to American clades, including polyploid groups in North America. For instance, North American taxa in S. sect. Physolychnis s.l. derive from Eurasian ancestors via at least three separate migrations, with poor resolution attributed to rapid radiation and homoplasy in chloroplast and nuclear markers. Hybridization has driven speciation across these lineages, as demonstrated by successful introgression between species diverged for about 6 million years, contributing to genetic diversity and adaptive radiation in regions like the Mediterranean and North America.[121]A pivotal evolutionary event is the origin of dioecy in S. sect. Melandrium (now often treated within S. subg. Behenantha), estimated at approximately 11 million years ago based on mutation rate estimates from genome resequencing of S. latifolia. This shift from hermaphroditism involved the evolution of young sex chromosomes, with the Y chromosome accumulating mutations over this timeframe. Recent 2025 genomic sequencing of S. latifolia has further elucidated the structure and evolution of its giant Y chromosome, supporting the estimated origin of dioecy around 11 million years ago.[41]Genomic features further illuminate these dynamics, as Silene harbors the largest known plant mitochondrial genomes, exceeding 11 Mb in species like S. conica, characterized by multichromosomal structures, high mutation rates (up to 50 times the angiosperm average), and extensive recombination. Cytoplasmic male sterility (CMS), linked to gynodioecy in species such as S. vulgaris, is associated with accelerated substitution rates in organelle genes that promote sexual system diversity.Despite advances, unresolved phylogenetic issues persist, including the polyphyly of traditional S. sect. Silene s.l., where molecular data place constituent species across multiple subgenera, necessitating revised circumscriptions. Ongoing 2025 studies employing restriction-site associated DNA sequencing (RAD-seq) are targeting cryptic species complexes, such as those in contact zones of closely related taxa, to clarify boundaries obscured by hybridization and incomplete lineage sorting. Evolutionary trends indicate that transitions to dioecy correlate with colonization of higher northern latitudes, potentially driven by climatic pressures favoring separate sexes for resource allocation, as seen in S. sect. Melandrium distributions.[120]