Streptocarpus

The genus is native to Afromontane biotopes[3] from central, eastern and southern Africa, including Madagascar and the Comoro Islands.

[4] The flowers are five-petalled, salverform[5] tubes, almost orchid-like in appearance, and hover or arch over the plant, while the pointed, elongate fruit is of a helical form similar to that of the "tusk" of a narwhal.

Although generally referred to simply as "Streptocarpus" or "Streps", the common name for subgenus Streptocarpus is Cape primrose, referring to the nativity of several species to South Africa and their superficial resemblance to the unrelated genus Primula.

[6] DNA studies have shown that, despite not having a twisted fruit, African violets evolved from within the Tanzanian Streptocarpus subgenus Streptocarpella.

In other unifoliates, the original leaf may die, but one or two new leaves will sprout from it, and the plant continues to grow.

[8] This subgenus (comprising plurifoliates and unifoliates) is unique in that, in winter, they can form abscission lines part way down the leaf (see photo gallery below).

In unifoliate species, the remaining healthy portion of that leaf will start to grow again from the base.

Their flowers are only about 2.5-3.5 cm in diameter, and their colour range seems to be limited to mid-purples, pale pinks, and white.

The diagram at the right shows a labelled drawing of a vertical cross-section along the length of a Streptocarpus flower.

As the anthers mature, they open slightly and act like a pepper shaker, which means that not all the pollen is released at once.

The leaves of some perennial, but usually unifoliate Streptocarpus, are unusual because, as winter approaches, they slowly die back to an abscission line midway down the leaf.

To help prevent unwanted cross-pollination, cover the newly fertilized stigma with a small plastic bag.

Once the pod is mature, it will turn brown, dry off, and split open along the spiralled seams to release the seeds.

For example, irradiation may be used (e.g. xrays, gamma rays) to induce mutations that may give rise to plants with new characteristics.

Another example is the use of colchicine to induce polyploidy (multiplying number of chromosomes) in plants, also to introduce new traits.

[16] Flowers now exist that are multicoloured, striped, spotted, veined, double, larger or smaller, and even fragrant and colour-changing.

The trait appears to produce a darker or more intense version of the colour of the outer edges of the petals.

Other genes are mentioned in the original articles,[44][45] but they appear to involve some rarely seen colour modifications.

It was accidentally introduced to Kew in 1853 in material surrounding trunks of tree ferns sent from Natal by Captain Garden.

In 1860, Mr Wilson Saunders sent a specimen to Kew, and it was eventually named Streptocarpus saundersii.

A similar plant raised from seed by Mr Lynch of the Cambridge Botanic Gardens, was eventually named Streptocarpus lutea.

The next plant to be introduced, Streptocarpus dunnii, played an important role in the production of “beautiful hybrids” of the day.

In 1884, seed was collected in the mountains of the Transvaal gold fields, and sent to Kew by Mr E. G. Dunn of Claremont, Cape Town.

In 1890, Streptocarpus galpini was introduced to Kew by Mr E Galpin, who found it on the “Bearded Man” peak that forms one of the boundaries of Swaziland.

It first appeared in England at Kew in seed contained in soil attached to tree ferns from South Africa.

It was raised by Mr Charles Green, who was at the time the gardener to Sir George Mackay of Pendell Court.

It was a hybrid of S. parviflorus and S. dunnii, and received the name of S. × Watsoni, after Mr Watson who raised the seed.

A host of progeny resulted with marked differences in colour, size, form and flower, and many were “decidedly attractive”.

Common activities include imparting knowledge, sharing plant material for propagation, and Streptocarpus shows.

Generally, to do well at shows, a specimen needs to have many perfect flowers, none faded or damaged; and many healthy, unblemished leaves.

Streptocarpella ( Streptocarpus saxorum )
Streptocarpus anatomy - cross section of flower
Streptocarpus liliputana , whole plant, on show
Streptocarpus liliputana flowers, close-up
Streptocarpus dunii
Streptocarpus eylsii , a unifoliate
Streptocarpus kentaniensis flowers
Streptocarpus seed capsule, showing "twisted" ( helical ) form referenced in the genus name - this being derived from the Greek for "twisted fruit"
Young rosulate Streptocarpus , whole plant
Streptocarpus molweniensis with clear abscission lines midway down the leaves
Streptocarpus seedling showing normally rudimentary second cotyledon
Streptocarpus 'Chorus Line' - a double-flowered variety
Streptocarpus 'DS-Heart of Kai' - a variety created in Ukraine
Streptocarpus saxorum in bloom
Streptocarpus rexii
Dibleys gold medal-winning Streptocarpus display, Chelsea Flower Show, May 2011