Caryophyllaceae.
The Pink or Carnation family has ca. 85 (80 to 101) genera with ca. 2000 (1750 to 2625) species.
The large number of Silene species (500 in 34 to 44 sections) creates problems depending on the genus
being loosely or strictly defined.
Also the frequent hybridisation makes classification difficult.
There are 75 species in 25 genera in Australia.
Most are weeds but many are important as garden plants and/or cut flowers such as the carnations and gypsophila.
Genera in Australia include Agrostemma – corncockles, Arenaria – sandworts, Colobanthus – pearlworts, Dianthus,
Drymaria, Gypsophila – baby’s-breath, Lychnis – campions, Paronychia – chickweeds, Sagina – pearlworts,
Saponaria – soapworts, Silene – campions, catchflies, Spergularia – sea-spurreys and Stellaria – chickweeds.
Almost all are annual or perennial herbs with a few lianas, subshrubs and small trees.
They may have tap roots or rhizomes with fibrous roots.
The stems are branched, most have swollen nodes and some are jointed.
A few have fleshy stems and leaves.
The simple leaves are opposite in most species with a few being alternate.
They can be so closely spaced they appear to be whorled.
Petioles are often present but may be very short and are sometimes absent.
The opposing petiole bases are often connected by a ridge.
Stipules are often present, sometimes prominent, they may be small or absent.
The blades are commonly linear to lanceolate but may be obovate, kidney or spatulate or cylindrical.
Each node can have one leaf or up to 4 with one being dominant.
The stomata (pores) may be on one or both sides of the blades.
Hairs of various types are present – with or without glands and simple or branched.
Terminal inflorescences are almost always a dichasial cyme or rarely a single flower.
(In cymes the terminal flower opens first and the inflorescence ceases to grow.
In a dichasial cyme two lateral branches grow from the main axis below the terminal flower again with
the terminal flower on each opening first.
This is repeated down the axis and each lateral branch may branch in a similar fashion.
The typical form of a dichasial cyme in Caryophyllaceae is a cincinnus which is coiled and dense with
2 rows of flowers alternating giving a zigzag appearance.
Dianthus is an example of this type of inflorescence.)
Flowers are mostly bisexual but there are some unisexual species.
Prominent leaf-like or dry bracts may be present and are usually paired.
There may occasionally be involucral bracts under the flowers such as in Dianthus.
The perianth mostly has 2 whorls but sometimes only one when the petals are absent.
Flower parts are typically in 5’s but occasionally they are in 4’s.
The sepals may be free or joined.
The calyx may be cylindrical or swollen and smooth or with bristles.
The sepals may have a keel, a hood, wings along the midrib or a leaf-like tip.
The petals are free and commonly clawed but they may be sessile.
The petal blade may be entire, bilobed or deeply cleft, or fringed or toothed.
The petals commonly have a corona or scale above the claw.
There is a nectiferous disc or separate nectaries.
There is almost never a hypanthium.
There is often a gynophore or an androgynophore.
There are 5 or 10 (1, 4 or 8) equal or unequal stamens in 1 or 2 whorls.
They are usually free but the bases may form a tube or they may be attached to the base of the sepals or petals.
The anthers open inwards via longitudinal slits.
Petaloid staminodes are occasionally present.
The superior ovary, of 2 to 5 or more united carpels is often on a stalk or gynophore.
There is 1 locule (sometimes more at the base due to septae) with 1 to many ovules.
Placentation can be free-central (1 locule with ovules attached to a free-standing central column);
axile (attached to the central axis of an ovary with 2 or more locules) or basal
(ovules attached at the base of the single locule).
There are 1 to 5 (6) styles that may be separate or joined at the base.
The stigmas, with papillae, are commonly linear along the inner surface of the style.
The fruit are mostly capsules with 1 locule, 2 to 10 teeth and more than one seed.
They mostly open by the teeth at the top (dentricidal capsule).
Some open by splitting between the locules or segments (valvular capsules).
The sepals persist in the fruit.
A few fruits are achenes, utricles or nutlets that have a single seed.
The seeds are sculptured.
J.F.
