The genus Wachendorfia consists of four species found exclusively in the Greater Cape Floristic Region. All four of them also occur at Phillipskop. The genus is easily identified on account of the strongly pleated lanceolate leaves, and many-flowered inflorescences of apricot to yellow flowers. A more unusual feature of Wachendorfia is that all the species are enantiomorphic. That is they have different forms of the flowers which are mirror images of each other (“enantio” means “opposite”, i.e. the other way around). In this case, while the petals are similarly arranged, the style on the flower is either sharply bent to the left or sharply bent to the right. The direction of the style is consistent within a plant but differs between plants in the same population (correctly termed as dimorphic enantiostyly!). In conjunction with the direction of the style, the stamen arrangement also differs. In every flower, there are two stamens pointing away from the style, and one stamen pointing the same direction as the style.
The purpose of enantiomorphy is to encourage cross-pollination between plants, as it is more likely that a left-styled plant will be pollinated by a right-styled plant due to the position of the extra stamen. However, the pollination of Wachendorfia is a bit of an enigma, as the stamens and style are held some way from the centre of the flower, where the nectaries can be found. It would therefore require a very broad insect to come into contact both with the pollen and to transfer it to the style of the next plant. It might be that it is actually the wings that transmit the pollen rather than the body of the insect. On top of this, the proportion of left to right-handed plants is not always 50:50 as one might expect. At Phillipskop, Wachendorfia paniculata plants have been recorded as 64% left-handed and 36% right-handed, so almost 2:1. Even more odd, 100% of the Wachendorfia brachyandra plants here are left-handed.
The commonest and most widespread species is Wachendorfia paniculata. This species is medium-sized in the genus, usually no more than 50cm high in our area, with wide branching loose panicle of flowers. The species is very variable and even in the Overberg there are several different forms with narrow leaves to very broad curved leaves. In size it is most similar to Wachendorfia brachyandra, but the stamens and style of Wachendorfia paniculata are almost as long as the petals.
Some forms of Wachendorfia brachyandra can look very similar to Wachendorfia paniculata but the species has much shorter stamens, usually less then half the length of the petals. In our area, the flowers are also considerably smaller than Wachendorfia paniculata, coming closer to Wachendorfia multiflora but on a much taller laxer inflorescence.
Wachendorfia multiflora is the smallest of the four species, both in stature and size of flowers. The inflorescence is often shorter than the leaves and the petals are less than 6mm wide. It also usually flowers in September, a month or more earlier than the other species. The other key difference is that the bracts holding the flowers tend to stay upright and green, whereas in the other species they quickly turn dry and brown, often bending downwards.
In contrast to all the other species, Wachendorfia thyrsiflora is a giant, reaching 2m or more in height. It produces a tightly packed spike of yellow flowers and is without doubt the most ornamental of the species. Even when not flowering the broad pleated leaves, which stay evergreen, make for good structural plants. Wachendorfia thyrsiflora is a marsh-loving plant, whereas the other species like stony dry soils, or in the case of Wachendorfia brachyandra, well-drained but with some seepage in winter.