Primulaceae

The Primulaceae /prɪmjəˈlʃ/, commonly known as the primrose family (but not related to the evening primrose family), are a family of herbaceous and woody flowering plants including some favourite garden plants and wildflowers. Most are perennial though some species, such as scarlet pimpernel, are annuals.[4]

Primulaceae
Primula vulgaris 'rubra' (Primevère rouge) - 15.jpg
Primula vulgaris 'rubra'
Scientific classification e
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Ericales
Family: Primulaceae
Batsch ex Borkh., nom. cons.[1][2]
Type genus
Primula L.
Synonyms[3]
  • Myrsinaceae R. Br. Prodr. Fl. Nov. Holland. 532. 1810 [27 Mar 1810] (as "Myrsineae") (1810)
  • Theophrastaceae

DescriptionEdit

 
Botanical drawing of Primula officinalis Jacquin. Legend: (A) the whole plant; (2) and (3) vertical cross-sections of the flower; (4) stamen; (5) horizontal cross-section of flower showing the calyx around the flower crown and stigma; (6) the stigma; (7) cross section through the ovary; (8) calyx; (9) seed; (10) cross section of seed[5]

StemsEdit

Primulaceae are mostly herbaceous, having no woody stem, except that some form cushions (spreading mats a few inches high) and their stems are stiffened by lignin. The stems can grow upright (erect) or spread out horizontally and then turn upright (decumbent).[6][7]

LeavesEdit

Leaves are simple, being directly attached to the stem by a petiole (stalk), but unlike the leaves of most flowering plants they have no stipules. The petiole is short or the leaf tapers gradually towards the base. Leaf arrangement is typically alternate but some are opposite or whorled, and there is generally a rosette at the base of the stem. The edges are toothed (dentate) or sawtoothed. New leaves in the bud are usually involute (rolled towards the upper surface) or conduplicate (folded upwards), but a few species roll downwards.[6][7]

FlowersEdit

Each flower is bisexual, having both stamens and carpels. They have radial symmetry; the petals can be separate or partially or fully fused together to form a tube-shaped corolla that opens up at the mouth to form a bell-like shape (as in item 8 in the figure) or a flat-faced flower. In most of the families of Ericales, stamens alternate with lobes, but in Primulaceae there is a stamen opposite each petal.[8]

The calyx has 4 to 9 lobes and persists after flowering.[7] They are grouped in unbranched, indeterminate clusters such as racemes, spikes, corymbs or umbels.[6]

Reproductive anatomyEdit

The fruit of Primulaceae begins as an ovary and inside it are the future seeds (ovules). These are attached to a central axis without any partitions between them (an arrangement called free central placentation; see item 7 in the figure), and they are bitegmic (having a double protective layer around each ovule). Unlike in most other families of Ericales, both layers form the opening at the top (the micropyle).[8]

Seeds and fruitEdit

As seeds develop, an endosperm grows around the embryo through free division of nuclei without forming walls (nuclear endosperm formation). The embryo forms a pair of short, narrow cotyledons (item 10 in the figure). Usually multiple seeds are in a capsule that is carried on a straight stalk (pedicel or scape). After it matures, it splits apart, releasing the seeds ballistically.[6]

TaxonomyEdit

HistoryEdit

The taxonomic history of Primulaceae has been long and complex. The botanical authority for the family name is given to August Batsch (1794),[1] as Batsch ex Borkh, using the term Primulae with six genera, the valid description being subsequently given by Borkhausen (1797).[a][9] Some earlier authors attributed the name to Ventenat (1799), as Primulaceae Vent.,[10] who described the Primulacées,[11] but Batsch had precedence.[2]

The most complete treatment of the Primulaceae family, with nearly 1,000 species arranged into 22 genera, was by Pax and Knuth in 1905 in the Engler system. They divided the family into five tribes (and several subtribes); Androsaceae, Cyclamineae, Lysimachieae, Samoleae and Corideae.[12][13] Many systems since have lacked consistency, but generally recognised two major groups as either tribes or subfamilies, the Lysimachieae and Primuleae (the Androsaceae of Pax and Knuth), with the largest genera being Primula, Lysimachia and Androsace.[14][13] In the Cronquist system (1988), Cronquist included the three closely related families, Primulaceae, Myrsinaceae and Theophrastaceae in the order Primulales based on morphological characteristics, in particular, ovaries with free-central placentation, a feature considered synapomorphic.[15] His circumscription of Primulaceae included about 800 species.[16] These three families were referred to as the primuloid families.[17] With the later development of molecular phylogenetic methods, the Primulales were found to be more closely related to other families within the Ericales, and the three primuloid families were subsequently absorbed into an expanded Ericales (Ericales sensu lato or s.l.), making 24 families within that order, where the primuloids formed a monophyletic clade.[8] It was also apparent that Myrsinaceae were paraphyletic, unless the genus Maesa was segregated and elevated to become a new monogeneric family, Maesaceae, but also that Primulaceae were probably paraphyletic.[18][19][17]

In the first consensus taxonomic classification, the Angiosperm Phylogeny Group (APG 1998), these proposals were recognised by including Primulaceae within Ericales, as Eudicots, forming one of three clades in the Asterids (Asteridae).[8][20] Maesa was formally segregated in 2000.[21] Further changes came from analysis of DNA sequence data. This led to the move of genera (primarily terrestial non-basal-rosette) from Primulaceae to Mysinaceae and Theophrastaceae. At this time Primulaceae was considered to consist of nine tribes (Primuleae, Androsaceae, Ardisiandreae, Lysimachieae, Glauceae, Anagallideae, Corideae, Cyclamineae, and Samoleae).[10] Notably, Lysimachieae were transferred to Myrsinaceae. This enlarged Myrsinaceae is distinguished as Myrsinaceae s.l. in comparison to the previous smaller family, Myrsinaceae s.s. (less Maesa).[13] These transfers, to preserve monophyly at the family level essentially left two tribes remaining in Primulaceae, the Primulae and Androsaceae, with about 15 genera sharing a number of common characteristics.[17][15][8] These additional changes were reflected in the 2003 revision of the APG system (APG II), where the now four primuloid families were among 23 in Ericales.[22] This restricted Primulaceae sensu stricto (s.s.) consisted of three groups: The Primulae, including Primula, the largest genus; the Androsaceae, including Androsace, the second largest genus; together with a small third group containing Soldanella Hottonia, Omphalogramma and Bryocarpum.[14] The APG third classification system (APG III, 2009) discussed all the taxonomic challenges arising from the phylogenetic studies, and placed all primuloid genera into one large Primulaceae s.l., corresponding to Cronquist's primulales. They stated that "The biggest problem for APG III was the question of how to treat Primulaceae and their immediate relatives, a closely related group that in the past has often been recognized as a separate order". The decision to treat all genera as a single famioly was based on the observation that the new circumscriptions had little in the way of apomorphies, but the entire group had numerous synapomorphies and were easy to recognise. This resulted in an Ericales with 22 families.[23] Consequently the four primuloid families were reduced to the rank of subfamilies within Primulaceae s.l..[24]

PhylogenyEdit

Primulaceae s.l. sensu APG III form part of the speciose (species rich) Asterid order Ericales s.l., with about 12,000 species and 22[b] families as per APG IV. Ericalees is one of four major clades within the asterids, where it is sister to the euasterids.[26] The phylogenetic structure of Ericales, as shown in the following cladogram, consists of seven major suprafamilial clades (eg balsaminoids, styracoids) and a group of "core" Ericales. Within the eracalean families, Primulaceae s.l. is shown as a sister group to Ebenaceae, and both are sister to Sapotaceae. These three families make up the primuloid clade.[25]

Evolution and biogeographyEdit

The fossil record of Primulaceae s.l. is sparse, but the crown group has been estimated as c. 46-61 million years old.[27] The crown primuloids have been dated to c. 102 mya, with Primulaceae/Ebenaceae divergence at 80 mya. Crown ages for the Primulaceae subfamilies vary from 24 mya for the Maesoideae, the basal group, to 70 mya for the Theophrastoideae.[25]

The primuloids probably originated in a shared Neotropical/Indo-Malaysian ancestral range, with the Primulaceae/Ebenaceae clade occupying the neotropics. Theophrastoideae is nearly all neotropical with a more recent migration out of the realm found in the aquatic Samolus genus. The divergence between Theophrastoideae and Primuloideae-Myrsinoideae at 70 mya repesents a vicariant event between the Neotropics and the Palearctic in the case of the latter. The Primuloideae orginating in thr Palearctic, persisted till the last 16 mya, when it started to shift into thr Nearctic.[25]

SubdivisionEdit

The three former families of the Primulales, together with the segregated Maesaceae, have been re-circumscribed into the broadly defined Primulaceae sensu lato (s.l.) The two uniting features of this family are a free central placenta and one stamen opposite each of the corolla lobes.[2][28][23] The cladogram below shows the infrafamilial phylogenetic relationships, together with the subfamilial crown ages. Maesoideae forms the basal group, while Primuloideae and Myrsinoideae are in a sister group relationship.[28][8][24][25]

Primulaceae s.l.

Maesoideae

24.1mya

Theophrastoideae

70mya

Primuloideae

46.4mya

Myrsinoideae

53.2mya

Christenhusz et al. (2016, 2017) list 2,790 species and 53 genera, varying from 1 in Maesoideae to 38 in Myrsinoideae, with 8 in Theophrastoideae and the remaining 6 in Primuloideae.[29][27] Byng (2014)[24] and Plants of the World Online list 55 accepted genera.[3][28][8][24][25] The generic limits of Myrsinoideae are not fully resolved.[30]

MaesoideaeEdit

Monogeneric subfamily: Maesa Forssk.

MyrsinoideaeEdit

The relatively large Myrsinoideae, has been treated as a number of tribes, eg Ardisieae, Lysimachiaeae and Myrsineae. Ardisieae and Myrsineae represent the woody clades within the subfamily.[25] Within the Myrsinoideae, the genera represented by the restricted Myrsinaceae s.s., prior to the transfers from the then Primulaceae, form a distinct clade.[30]

PrimuloideaeEdit

Includes the tribes Androsaceae and Primulae.[17]

TheophrastoideaeEdit

EtymologyEdit

The Primulaceae are named for their nominative and type genus, Primula. Linnaeus used this name to reflect its place among the first flowers of spring, given the primrose's vernacular Latin name of primula veris (lit.'little first of spring' ), primula (feminine diminutive primus, first + veris (genitive ver, spring).[11]

Distribution and habitatEdit

Distribution is cosmopolitan.[25]

CultivationEdit

The British National Collection of Double Primroses is held at Glebe Garden, at North Petherwin, in North Cornwall.[31][32][33]

GalleryEdit

NotesEdit

  1. ^ "More additions affectingconserved familial names are from Batsch (1794),which is to be considered as the place for valid publication of Melanthiaceae and Primulaceae, bothaccepted and conserved with the authorship of‘Batsch ex Borkh. 1797’ but validly published in 1794by a reference in the introduction of that book to thecorresponding descriptions in Batsch (1786)"[2]
  2. ^ Ericales has 21 or 22 families, depending on whether Sladeniaceae is recognised as separate from, or submerged in Pentaphylacaceae[25]


ReferencesEdit

  1. ^ a b Batsch 1793–1794, ii 395.
  2. ^ a b c d APG IV 2016.
  3. ^ a b POWO 2021.
  4. ^ "Primulaceae - Primrose Family". PlantLife.org. Retrieved 18 June 2021.
  5. ^ Thomé 1903.
  6. ^ a b c d Anderberg 2004.
  7. ^ a b c Xu, Zhenghao; Chang, Le (2017). "2. Primulaceae". Identification and control of common weeds. Volume 3. Springer. pp. 51–82. ISBN 9789811054037.
  8. ^ a b c d e f g Anderberg et al 2002.
  9. ^ Borkhausen 1797, p. 240.
  10. ^ a b Takhtajan 1997, p. 200.
  11. ^ a b Ventenat 1799, vol. ii pp. 289–291.
  12. ^ Pax & Knuth 1905.
  13. ^ a b c Martins et al 2003.
  14. ^ a b Schneeweiss et al 2004.
  15. ^ a b Mast et al 2001.
  16. ^ Cronquist 1988, pp. 357–359.
  17. ^ a b c d Kallersjo et al 2000.
  18. ^ Anderberg & Ståhl 1995.
  19. ^ Anderberg et al 1998.
  20. ^ APG I 1998.
  21. ^ Anderberg et al 2000.
  22. ^ APG II 2003.
  23. ^ a b APG III 2009.
  24. ^ a b c d Byng 2014.
  25. ^ a b c d e f g h Rose et al 2018.
  26. ^ Schonenberger et al 2005.
  27. ^ a b Christenhusz et al 2017, p. 494.
  28. ^ a b c Soltis et al 2018.
  29. ^ Christenhusz & Byng 2016.
  30. ^ a b Yan et al 2019.
  31. ^ "Glebe Garden". Glebe Garden.
  32. ^ Byfield, Andy (June 2, 2015). "Double primroses: pretty, difficult" – via www.theguardian.com.
  33. ^ "CORNWALL GARDENS TRUST » Events » Double Primroses (National Primrose Collection) Launceston, PL15 8JX". www.cornwallgardenstrust.org.uk.

BibliographyEdit

BooksEdit

ChaptersEdit

  • Stahl, B; Anderberg, A. A. (2004). Maesaceae. pp. 255–257., in Kubitzki (2004)
  • Anderberg, A. A. (2004). Primulaceae. pp. 313–319., in Kubitzki (2004)
  • Stahl, B; Anderberg, A. A. (2004). Myrsinaceae. pp. 266–281., in Kubitzki (2004)
  • Stahl, B (2004). Theophrastaceae. pp. 472–478., in Kubitzki (2004)

Historical sourcesEdit

ArticlesEdit

  • Anderberg, Arne A.; Ståhl, Bertil (1995). "Phylogenetic interrelationships in the order Primulales, with special emphasis on the family circumscriptions". Canadian Journal of Botany. 73 (11): 169–91730. doi:10.1139/b95-184.

EricalesEdit

MaesoideaeEdit

  • Anderberg, Arne A.; Ståhl, Bertil; Källersjö, Mari (May 2000). "Maesaceae, a new primuloid family in the order Ericales s.l.". Taxon. 49 (2): 183–187. doi:10.2307/1223834. JSTOR 1223834.

MyrsinoideaeEdit

  • Anderberg, Arne A.; Manns, Ulrika; Källersjö, Mari (2007). "Phylogeny and Floral Evolution of the Lysimachieae (Ericales, Myrsinaceae): Evidence from ndhF Sequence Data". Willdenowia. 37 (2): 407–421. JSTOR 20371369.
  • Yan, Xiaokai; Liu, Tongjian; Yuan, Xun; Xu, Yuan; Yan, Haifei; Hao, Gang (2019). "Chloroplast Genomes and Comparative Analyses among Thirteen Taxa within Myrsinaceae s.str. Clade (Myrsinoideae, Primulaceae)". International Journal of Molecular Sciences. 20 (18): 4534. doi:10.3390/ijms20184534.

PrimuloideaeEdit

TheophrastoideaeEdit

APGEdit

WebsitesEdit

External linksEdit