Primulaceae

Primulaceae, the primulaceae, are a family of annual or perennial phanerogamous plants (rarely bushes), with 22 genera including well-known garden plants such as primroses and wild flowers.
Some 800 species, most of them cosmopolitan, from the temperate and cold regions of the boreal hemisphere, many from mountains (Vitaliana primuliflora) and others from aquatic ones (Salomus valerande).

Features

They are characterized by their simple, opposite (Anagallis), whorled (Lysimachia vulgaris), true (Androsace) or false (Primula) rosette leaves. Hermaphroditic flowers, almost always actinomorphic or zygomorphic, generally pentameric, gamopetalous, with superior ovary or sometimes semi-inferous, unilocular, with basal placentation, with heterostyly; solitary or in umbels on a scape. Fruits in capsule or pixidium.

Description

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

The family shares a number of characteristics, such as haplostemonic flowers that have the same number of petals and stamens, sympetalae corollas that have united petals, stamens opposite the petals, free central placentation, bitegmic (two-layered) ovules. and nuclear endosperm formation.

Stems

Primulaceae are mostly herbaceous, with no woody stem, except that some form cushions (mats extending a few centimeters high) and their stems are hardened by lignin. Stems can grow upright or spread horizontally and then become upright (decumbent).

Leaves

The leaves are simple, being attached directly to the stem by a petiole (stalk), but unlike the leaves of most flowering plants they do not have stipules. The petiole is short or the leaf tapers gradually towards the base. The arrangement of the leaves is normally alternate, but some are opposite or upright, and there is usually a rosette at the base of the stem. The edges are jagged or saw-toothed. New leaves on the shoot are usually involute (rolled toward the upper surface) or conduplicate (folded up), but a few species roll downward.

Flowers

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

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

Reproductive Anatomy

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

Seeds and fruits

As seeds develop, an endosperm grows around the embryo by freely dividing nuclei without forming walls (nuclear endosperm formation). The embryo forms a pair of short and narrow cotyledons (point 10 of the figure). The multiple seeds are usually in a capsule that is carried on a straight stalk (pedicel or escape). After maturing, it splits, releasing the seeds ballistically.

Subfamilies

• Maesoideae
• Myrsinoideae
• Primuloideae
• Theophrastoideae

Genres

• Androsace L. - Rosette leaves.
  

  Dodecatheon
• Bryocarpum Hook. f. " Thomson
• Centunculus
• Cortusa L.
• Dionysia Fenzl.
• Dodecatheon L.
• Douglasia Lindl.
• Heberdenia Banks ex A. DC.
• Hottonia L.
• Kaufmannia Regel.
• Prímula L. primula, leaves in false rosette, actinomorfa flower.
• Samolus L.
• Soldanella L.
• Vitaliana Sesl.

The following genera traditionally included in the family primulaceae, should, according to Källersjö et al. (2000), belong to the family Myrsinaceae:

• Anagallis opposite leaves, fruit in pixide.
  • Anagallis arvensis L., murage;
    

    Anagallis arvensis
  • Anagallis crassifolia Thore;
    

    Lysimachia nummularia
  • Anagallis foemina Miller;
  • Anagallis minima (L.) E. H. L. Krause,
  • Anagallis monelli L.,
  • Anagallis tenella (L.) L.
• Ardisiandra Hook. f.
• Asterolinon
  • Asterolinon linum-stellatum (L.) Duby
• Coris
  • Coris monspeliensis L.,
  • Coris hispanica
• Cyclamen ciclamen
  • Cyclamen balearicum Willk, pamporcino.
• Glaux
  • Glaux maritima L., in saladares.
• Lysimachia
• Pelletiera A. St.-Hil.
• Trientalis L.

Synonymy

• Aegicerataceae Blume
• Anagallidaceae Batsch ex Borkh.
• Ardisiaceae Juss.
• Coridaceae J. Agardh
• Embeliaceae J. Agardh
• Lysimachiaceae Juss.
• Maesaceae Anderb. et al.
• Myrsinaceae R. Br., nom. cons.
• Samolaceae Raf.
• Theophrastaceae D. Don, nom. cons.