The Caryophyllaceae, commonly called the pink family or carnation family, is a family of flowering plants. It is included in the dicotyledon order Caryophyllales in the APG III system, alongside 33 other families, including Amaranthaceae, Cactaceae and Polygonaceae.^[1] It is a large family, with 86 genera and some 2,200 species.^[2]

This cosmopolitan family of mostly herbaceous plants is best represented in temperate climates, with a few species growing on tropical mountains. Some of the more commonly known members include pinks and carnations (Dianthus), and Firepink and campions (Lychnis and Silene). Many species are grown as ornamental plants, and some species are widespread weeds. Most species grow in the Mediterranean and bordering regions of Europe and Asia. The number of genera and species in the southern hemisphere is rather small, although the family does contain Antarctic Pearlwort (Colobanthus quitensis), the world's southernmost dicot, which is one of only two flowering plants found in Antarctica.^[3]

Description

Despite its size and the somewhat doubtful mutual relationships, this family is rather uniform and easily recognizable.

Most are herbacaceous annuals or perennials, dying off above ground each year. A few species are shrubs or small trees, such as some Acanthophyllum species.^[4] Most plants are non-succulent, i.e. having no fleshy stems or leaves. The nodes on the stem are swollen. The leaves are almost always opposite,^[5] rarely whorled. The blades are entire, petiolate and often stipulate. These stipules are not sheath-forming.

The hermaphroditic flowers are terminal, blooming singly or in branched or forked in cymes. The inflorescence is usually dichasial at least in the lower parts, which means that in the axil of each peduncle (primary flower stalk) of the terminal flower in the cyme, two new single-flower branches sprout up on each side of and below the first flower.^[4] If the terminal flowers are absent, then this can lead to monochasia, i.e. a monoparous cyme with a single flower on each axis of the inflorescence. In the extreme, this leads to a single flower, such as in Githago or Arenaria.^[4] The flowers are regular and mostly 5-merous, i.e. with 5 petals and 5 sepals, but sometimes with 4 petals.^[5] The sepals may be free from one another or united. The petals may be entire, fringed or deeply cleft. The calyx may be cylindrically inflated, as in Silene. The stamens number 5 or 10 (or more rarely 4 or 8),^[5] and are mostly isomerous with the perianth. The superior gynoecium has 2 to 5 carpels (members of a compound pistil) and is syncarpous, i.e. with these carpels united in a compound ovary. This ovary is 1-locular, i.e. having one chamber inside the ovary. The fruit is a utricle or capsule containing a single seed.^[5]

Systematics

The "maiden pink", Dianthus deltoides, belongs to the core group of Silenoideae.

Minuartia gerardii belongs to a clade traditionally included in the Alsinoideae.

Paronychia argentea from the primitive Paronychioideae assemblage

Stellaria ruscifolia is traditionally placed in the Alsinoideae, but may not be a close relative of Minuartia.

Currently, Amaranthaceae and Caryophyllaceae are sister groups and considered closely related.

Formerly, Caryophyllaceae was considered the sister family to all of the remaining members of the suborder Caryophyllineae because they have anthocyanins, and not betalain pigments. However, cladistic analyses indicate that Caryophyllaceae evolved from ancestors that contained betalain, reinforcing betalain as an accurate synapomorphy of the suborder.^[6]

This family is traditionally divided in three subfamilies, which are the:

• Alsinoideae: no stipules; petals not united
• Silenoideae: no stipules; petals united
• Paronychioideae: with fleshy stipules; petals separate or united.

The last, however, are a basal grade of rather primitive members of this family, not closely related but simply retaining many plesiomorphic traits. Instead of a subfamily, most ought to be treated as genera incertae sedis, but Corrigiola and Telephium might warrant recognition as Corrigioleae. The Alsinoideae on the other hand seem to form 2 distinct clades, perhaps less some misplaced genera. Finally, the Silenoideae appear monophyletic at least for the most part, if some of the taxa misplaced in Alsinoideae are moved there; it may be that the name Caryophylloideae would apply for the revised delimitation.^[7]

However, there is rampant hybridization between many members of this family – particularly in the Silenoideae/Caryophylloideae – and it has been found that in some the lineages of descent are highly complicated and do not readily yield to cladistic analysis.^[8]

Genera

References