Rosaceae Rose Family

The flowers of the rose family contain a hypanthium - a floral tube or vase formed by the fusion of the corolla (petals), the calyx (sepals) and the filaments of the stamens. In hypogynous flowers, the perianth (sepals and petals) and stamens are attached to the receptacle (swollen end of the flower-bearing axis) below the gynoecium (female parts). The ovary is then known as superior (attached above the other parts).

In perigynous flowers, however, the petals, sepals and stamens fuse into a floral tube which surrounds the superior ovary to form a hypanthium. The free ends of the sepals, petals and stamens are attached to the hypanthium rim. An example is the Rose (Rosa).

In epigynous flowers the hypanthium is fused to the female parts so that the free ends of the sepals, petals and stamens appear attached to the top of the gynoecium. The ovary is inferior (attached below the other parts). Examples are Malus (apple) and Pyrus (pear) which also belong to the Rose family.

Diagram of Rosa morphology (I would have included the image here but the international tag system is too complex).

Fragaria (strawberries)

Above and below: Fragaria vesca, Wild Strawberry. The familiar strawberry fruit consists mainly of the fleshy/succulent receptacle in which separate achenes are embedded. An achene is a dry indehiscent fruit in which a single carpel encloses a single seed and as the derivative of the carpel is the fruit proper or 'true fruit'. The fleshy receptacle constitutes what is sometimes called the 'false fruit' or pseudocarp.

Potentilla (Cinquefoils)

Below: Potentilla sterilis, the Barren Strawberry.

Below: Potentilla reptans (Creeping Cinquefoil)

Below: Silverweed (Potentilla anserina)

Prunus

Above and below: cherry (Prunus) blossom is a must see in early Spring. Cherry trees belong to the diverse rose family (Rosaceae) along with the hawthorn tree (Crataegus), brambles and blackberries (Rubus), pear (Pyrus), apple (Malus), Rowan, Whitebeams and Wild Service-Tree (Sorbus), Blackthorn or Sloe (Prunus spinosa), a variety of herbaceous plants such as strawberry (Fragaria), Agrimony (Agrimonia) and of course roses (Rosa).

Malus sylvestris (Crab Apple)

The familiar fruit of the apple is derived from an epigynous flower with an inferior ovary. The carpels are fused into a syncarp (the gynoecium is syncarpous). The internal walls (endocarp) of the fused carpels form tough fibrous tissue whilst the outer carpel walls form fleshy tissue that drives wedges between the separate carpels. The pips inside the carpels are seeds. This forms the core of the fruit and is surrounded by the succulent hypanthium which is fused to the carpels. Such a fruit is called a pome and is found in Apple (Malus), Pear (pyrus), Quince, Medlar, Service Tree and Hawthorn. Below: fruit from the same tree whose flower was photographed above.

Hawthorn(Crataegus)

The Hawthorn is also called the May-tree or Mayflowersince there flowers open around May.

Above:Hawthorn (left) and Cherry (right).

Above and below: examination of the leaves reveals which species of hawthorn we are dealing with: the leaves are deeply divided (to more than half-way) and do not taper gradually to the leaf-stalk, so this is Crataegus monogyna (Hawthorn). The flowers also possess a single style.

The fruit of Hawthorn is a pome (though often referred to as a 'berry') like the apple, but much smaller, softer and less succulent.The fruit and leaves are edible, though not especially tasty. The 'berries' have been used to make wine.

The wood of Hawthorn apparently makes excellent firewood (even when green) and charcoal.Hawthorn is a small tree or shrub and a rapid colonizer associated with scrub.

Rosa (Rose)

Above and below: Dog Rose (Rosa canina).

The fruits of the rose are called rose hips and develop from the fertilized hypanthium. Below: rose hips of Rosa rubiginosa (Sweet-briar). Similar to those of Rosa canina, but in the former the sepals generally persist (attached to the top of the fruit) and are pinnately lobed and covered with sticky glandular hairs. This plant occurs on grassland and scrub, especially on calcareous soils. (Here growing in scrub on chalky soil).

Rubus

Burnets

Sanguisorba officinalis or Great Burnet has been used in traditional medicine to treat inflammation, help blood clotting and to treat pain. Research has shown that terpinoids and related compounds and the polysaccharide fraction of the root does indeed have medicinal potential. It has antioxidant properties and reported anti-cancer effects in cell culture (inducing apoptosis in prostate cancer cells for example).

Above: Poterium sanguisorba (Sanguisorba minor) or Common Salad Burnet growing in calcareous grassland in the Kent (South of England, UK). The globular flower head bears female flowers towards the apex and male or perfect flowers (with both male and female parts) towartds the base. In the example shown here only the apiocal female flowers have opened, exposing their brushlike reddish stigmas. The flower heads vary from just under half an inch to just under an inch in length.

Agrimonia eupatoria or Agrimony

Below: Agrimony flowers have five sepals, forming a calyx tube with five teeth, and five petals. Once the flower is pollinated and the petals shed, the calyx teeth close over and indurate (harden, becoming woody in texture) and the teeth become connivent (they close together by arching inwards) and the entire tube acquires 10 furrows and the apical ring develops into several rows of hooked spines. These spines are of interest to engineers looking at possible methods of developing better velcro-like materials: they are used in fruit dispersal, attaching to animal fur to be transported to new sites. Notice that the pedicel (a stalk bearing an individual flowers) also bends downwards when the fruit develops.

The hooks on the fruit of Agrimony are useful in determining species. In Agrimonia eupatoria shown here, the outermost hooks may be horizontal (projecting at 90 degrees) but more often projecting slightly forwards towards the apex (as in this case), but are never reflexed (projected backwards towards the base). In contrast, in Fragrant Agrimony Agrimonia procera (Agrimonia odorata) the outermost hooks are reflexed. This false-fruit formed by the modified sepals contains usually a single true dry fruit or achene.

References

Zhang, L., S.R. Koyyalamudi, S.C. Jeong, N. Reddy, P.T. Smith,
R. Ananthan,and T. Longvah, 2012. Antioxidant and immunomodulatory activities of polysaccharides from the rootsof Sanguisorba officinalis. Int. J. of Biological Macromolecules 51: 1057– 1062.

Zhang, L., S. R. Koyyalamudi, S. C. Jeong, N. Reddy, Paul T. Smith,
R. Ananthan and T. Longvah, 2012. Methanol extract of Sanguisorba officinalis L. with cytotoxic activity against PC3 human prostate cancer cells. Mol. Med. Reports 6: 670-674.

Article updated: 24 July 2020, 18 Aug 2020