Haemanthus (family Amaryllidaceae) is a well known genus and is widely spread among amateur growers of bulbs and succulents in north-west Europe. Less known is the Haemanthus-allied genus Scadoxus. I don't know why plants of this genus are not better known. In general Scadoxus species are easily propagated by seeds. Furthermore they are easy to grown and request no special treatment- they are "tolerant".
Friis and Nordal (1976) established that the Haemanthus subgenus Nerissa significantly differs from the subgenus Haemanthus. Based on the distribution patterns and morphological differences it can be concluded that the two subgenera represent two evolutionary lines which are seperated at a very early stage. They divided the genus Haemanthus into two genera: Haemanthus and the new genus Scadoxus (table 1).
According to Bjornstad and Friis (1972) the oldest available name for the subgenus Nerissa is Scadoxus. This was first published by Rafinesque in 1836. He divided Haemanthus into four closely related genera: Leucodesmis, Perihaema, Scadoxus and Nerissa. In this turn Salisburry in 1866 divided the genus Haemanthus into five genera: Diacles, Haemanthus, Melicho, Hyaxis and Nerissa. The first three genera have a bifarious, truncate bulb and sessile, unsheathed leaves and have a distinguished involucral features. The species of the genera Gyaxis and Nerissa have sheathed petiolate leaves and conical to spherical bulbs. In 1888 Baker changed the genera as published by Salisburry into subgenera of Haemanthus. In later years experts in this field considered the subgenus Nerissa different from the other subgenera. Some species of the subgenus Nerissa have an elongated rhizome, and the position of the penducle compared to the leaves is different.
Table 1. Differences between the genera Haemanthus and Scadoxus according to the key given by Friis and Nordal (1976).
| Characteristic | Haemanthus | Scadoxus |
|---|---|---|
| Bulb | bifarious | rhizomes or globose bulb with rhizomatous parts |
| Leaves | distichous, usually thick and fleshy, no distinct middle nerve, sometimes hairy | not distinctly distichous, herbaceous in texture, distinct middle nerves, always glabrous |
| Distribution | South Africa and Namibia | tropical Arabia and Africa as far south as Namibia and East Cape |
Salisburry's division provided the basis for division of Haemanthus into Haemanthus and Scadoxus by Friis and Nordal. The type species is Scadoxus mulitflorus (syn. H. multiflorus). Friis and Nordal distinguished eight Scadoxus species: S. cyrtanthiflorus, S. cinnabarinus, S. longifolius, S. membranaceus, S. multiflorus, S. nutans, S. pole-evansii, S. pseudocaulus and S. puniceus.
Scadoxus multiflorus can be described as a herb, 15-120 cm tall, with rhizomatous bulb, 2-8 leaves, forming a 5-60 cm long false stem, lanceolate to ovate leaves, 8-45 cm long and 3.5-15 cm broad. The leaves appear during or after the anthesis. The impressive inflorescence, 5-26 cm in diameter, consists of 10-200 flowers. The perianth tube has a red colour (Bjornstad and Friis, 1974).
Scadoxus multiflorus includes three subspecies: ssp. katherinae, ssp. longitubus and ssp. multiflorus. The three major differences between the subspecies are height of the plant, length of the perianth tube and the breadth of the perianth segments (table 2).
Table 2. Differences between Scadoxus multiflorus ssp. katherinae, ssp. multiflorus and ssp. longitubus (Friis and Nordal, 1976).
| Characteristic | ssp. katherinae | ssp. multiflorus | ssp. longitubus |
|---|---|---|---|
| Perianth tube | > 16 mm | > 15 mm | > 15 mm |
| Perianth segment | 2.2 - 4.0 mm | >2.5 mm | 1.4 - 3.5 mm |
| Plant height | up to 120 cm | small to robust | up to 65 cm |
| Habitat | coastal bush | lowland rainforest | |
| Distribution | Kwazulu-Natal, three Cape provinces and southern Swaziland | eastern and southern Africa | Guinea to Ghana |
Literature
Bjornstad, I.N. and I. Friis. 1972. Studies on the genus Haemanthus (Amaryllidaceae) I. The Infrageneric Taxanomy. Norw. J. Bot. 19, 197-206.
Bjornstad, I.N. and I. Friis. 1974. Studies on the genus Haemanthus (Amaryllidaceae) II. A revision of the sections Gyaxis and Nerissa.Norw. J. Bot. 21, 243-275.
Bjornstad, I.N. and I. Friis. 1976. Studies on the genus Haemanthus (Amaryllidaceae) IV. Division of the genus into Haemanthus s.str. and Scadoxus with notes on Haemanthus s.str. Norw. J. Bot. 23, 63-77.