BOBBEJAANTJIES the Genus Babiana

BOBBEJAANTJIES The genus Babiana by Peter Goldblatt, Missouri Botanical Garden, St. Louis, U.S.A. and John C. Manning, National Botanical Institute, Kirstenbosch. abiana, a member of the so conspicuous in the western geophytes, that is, they have Iridaceae (iris family], is part of the southern African underground storage organs that B one of the larger genera of subcontinent. Curiously, one allow them to become dormant this important southern African species, Babiana hypogea, extends during the dry part of the year. In plant family. Babianas in English, widely across the drier parts of the autumn, as temperatures drop bobbejaane or bobbejaantjies in eastern southern Africa, as well as and the winter rains begin, the Afrikaans, the genus is quite well Botswana, Namibia, Zimbabwe corm sprouts and new leaves are known to the inhabitants of the and southern Zambia. One more produced. Then, if rainfall is south-western part of southern species occurs on the Indian sufficient, the plants flower and Africa, but perhaps only to bulb Ocean island of Socotra, a truly produce seed. As seeds mature a enthusiasts and new corm is also indigenous formed under gardeners ground to replace elsewhere. The the old one, the origin of the food reserves of common name which have been probably reflects a used up by the popular belief that season's growth the corms, the and reproductive underground effort. Like many storage organ of plants of dry babianas, were a habitats, babianas favourite food of adapt to poor baboons. The seasons, when the popular name, rains fail or are originally in Dutch inadequate, by babianer or recycling their baviaantjes, in fact food reserves into gave rise to the a new corm botanical name for The conventional babiana flowers of Babiana ambigua make a charming display without producing in the veld in the south-western Cape and are especially common after fire has flowers or seeds, the genus, opened up the vegetation cover. Their sweet scent compliments the bright blue Babiana which flowers with white nectar guides. Pholo: John Manning. but plants almost was erected in always produce a 1801 by the English botanist, remarkable pattern of geographical few leaves even in the driest John Gawler. distribution. Socotra, like the years. There are approximately south-western Cape, also has a Because plants produce a new seventy wild species of babiana, winter-rainfall, summer dry corm year after year, individual all but a few of them confined to climate and so the species there babianas can live for many years. the south-western Cape, reflects the marked preference of No one has managed to determine Namaqualand, and south-western the genus for this climate regime. how long babianas (or any other Namibia. The genus is easy to How B. socotrana actually reached corm-bearing plants) live, but recognize, for almost all the Socotra is an enigma. It has been potentially plants may be dozens species have softly hairy to argued that during past phases of or even hundreds of years old. velvety leaves and stems, and the climatic aridity a corridor of arid We suspect this seldom happens leaf blades are pleated. This is climate existed across central because corms are a tasty treat for such an unusual adaptation that Africa to Somalia and it was via all sorts of animals. In the wild or babianas can always be distin this pathway that the genus even in gardens close to wild guished by their leaves alone. reached far-away Socotra. habitats, corms are often dug up Plants seem primarily adapted to Presumably babianas once grew by porcupines and baboons who fairly dry habitats. Modest winter on the East African mainland as feast on the starch-filled nuggets rainfall and hot dry summers well. of food. Insect grubs burrow into seem to suit the genus admirably, Like nearly all members of the the corms and eat their fill before hence the evolutionary radiation iris family, babianas are reaching adulthood. Molerats also 12 Veld &' Flora March 2001 live on corms of babianas and many other native plants with corms or bulbs. Babianas have adapted to survive predation. While the large, main corm may be destroyed, plants also produce tiny cormlets in the underground leafaxils that will ensure survival for future seasons. Predation by molerats is so common that many cormous plants actually depend on it for local dispersal, thus turning an unavoidable hazard into a mode of survival and of increasing the range of the species. Molerats usually transport corms to nests where they store food. As they carry corms and their attached leaves about, the cormlets fall randomly in the underground tunnels leading to nests. In this way plants may become dispersed over many metres in just a year and over the centuries may be dispersed over considerable distances. This pattern of vegetative dispersal is valuable for survival of a species in the short term. In evolutionary time however, plants must also reproduce sexually by means of seeds to maintain genetic diversity and in doing so adapt to changing conditions. There are three main groups of species in the genus. A group of largely Western Cape species, section Babiana, have an adaptation unique in the Iridaceae: the inner floral bracts The u\lusual, radially symmetric flowers of Babiana pygmaea are the largest in the are divided to the base, and thus genus. This rare, Cape west coast plant is now known from a few isolated populations appear as two separate structures. and may soon be lost in the wild. Pholo; John Manning. Many species of this group have remarkable stamens that have a distinctive, cobwebby covering. an adaptation to avoid being arrow-shaped anthers, with a The remaining species, almost eaten? G. J. Lewis, whose revision broad connective between the half the genus, have no particular of Babiana was published in 1959, anther lobes, and anthers and defining feature but can be recog did not regard the species with pollen are coloured dark blue to nized by their inner floral bracts truncate leaves as immediately blackish. Most of the species with that are notched at the tips or related, suggesting that this highly these specialized anthers also divided for a short distance. specialized leaf type arose have radially symmetric flowers Several species of this group have independently three times. If she which has important conse striking adaptations. Babiana was correct, this is quite quences for their reproductive pygmaea of the Cape west coast, remarkable, for similar truncated biology. A second group, section with huge, yellow, salver-shaped leaves are unknown in other Exohebeoides, mostly found in flowers with a brownish center, is Iridaceae, or in fact in any other Namaqualand and the dry parts of now severely threatened as its southern African plants. Another the north-west Cape, have habitat, fertile lowlands, is largely leaf specialization in the genus is curiously modified leaves, often given over to agriculture. Three the rigid, coarsely fibrous leaf of with the margins wavy or curled, Namaqualand and western Karoo the Namaqualand species, or the leaves themselves may be species have amazing, truncate B. dregei, the tip of which forms a loosely coiled. The leaves of these leaves that look for all the world sharp thorny spike which will species are sparsely or not at all as if they have been chewed in pierce the skin even through a hairy, but often the leaf bases have half by a buck or tortoise. Is this thick pair of jeans. These various Veld &- Flora March 2001 13 Above. Long-proboscid flies are drawn to intensely coloured flowers such as those ofBabiana dregei and can sometimes be seen in Namaqualand feeding on the nectar of these long-tubed flowers. Right. The Namaqualand Babiana lorla makes a brave appearance in winter, before the spring annuals have germinated. Plants survive in rock crevices where water accumulates after light rain or heavy dew and the corms are protected from predation. Far right. The pale coloured and strongly scented flowers of Babiana virginea appear to be adapted for moth pollination. This species is a narrow endemic of the Roggeveld Escarpment north-west of Sutherland. Photos: John Manning. leaf modifications, imposed on the hidden under the arching dorsal species, Babiana ringens (see pleated and often hairy basic tepal, is dusted onto a bee's back. cover) has a unique adaptation to babiana leaf, appear to relate to When the bee visits another facilitate bird pollination. The protection from herbivory. Like flower, pollen will in turn be main stem of the plant forms a many other Iridaceae, the leaves transferred to receptive stigmas, stiff, sterile perch and the flowers are edible and contain no held in exactly the same position are produced on side branches poisonous or foul-tasting under the dorsal tepal. The offer below the perch. compounds. They are rendered of nectar is thus a reward to an Other floral adaptations in unattractive to grazing animals by insect that in turn transfers pollen babianas closely parallel those in their tough fibrous nature, from onGl plant to another, other plants of the southern spikiness, or unappetizing initiating the reproductive cycle African winter-rainfall zone. appearance. that will lead to the production of Species like Babiana flabellifolia, Much of the diversity in seeds. B. framesii, B. pubescens and babianas relates directly to their Perhaps the most striking several more, have flowers with sexual reproduction. Their flowers adaptations in babianas are the an extended floral tube, usually are extremely variable and reflect flowers modified for pollination over 4 cm long, and are pollinated adaptations to a host of different by birds. So altered is the floral by tangle-veined flies (family pollinators.

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