One of the commonest plants in the islands of Bougainville Straits is the Eranthemum variabile, which is frequently found growing at the sides of the paths. The spurges, Euphorbia pilulifera and E. Atoto, are usually found in the waste-ground around villages. In the cultivated patches clumps of the handsome flowering reed, Pennisetum macrostachys (“orsopa”), which grows to a height of nine or ten feet, are often conspicuous. In one place may be seen the tall shrub, Kleinhovia Hospita (“lafai”), the inflated fruits of which are eaten by the cockatoos. In another place the botanist may recognise the Canna indica (Indian Shot: “sati”), and near by perhaps Coix Lachryma (Job’s tears: “ken-ken”), both of which plants have been probably introduced originally from the Malay Archipelago. Solomon Islanders occasionally wear the seeds of Coix Lachryma as a personal ornament. They are also used for this purpose by the Admiralty Islanders, and by the natives of some parts of New Guinea. Scented labiate plants are very frequent in the waste-ground of the plantations, and the natives are fond of wearing them in their armlets. Amongst them I may mention Moschosma polystachyum (“pipituan”) and Ocymum sanctum (“kiramma”). The “luk-a-luk” (Evodia hortensis), which is a favourite scented plant, is commonly found in the same situations. The tiny plant, Oxalis corniculata, may clothe a bare patch of ground; whilst in another part of the plantation, Commelyna nudiflora may similarly be observed. Numerous composite plants, such as Vernonia cinerea, Adenostemma viscosum, etc., form a conspicuous feature among the rubbish-plants in these cultivated patches. The Codiæum variegatum (“tiatakush”), with its very singularly-shaped leaves, is also to be seen: and, amongst other plants, I should refer to Solanum vitiense and Crotalaria quinquefolia. Tall sedges, such as Cyperus canescens and Mariscus phleoides, are to be commonly observed. Lastly, I should notice two small scitamineous plants, the “nakia,” a wild ginger, and the “temuli,” the root of which has medicinal properties, whilst its yellow juice is used for staining purposes.
A species of Pachyma ? ?
Whilst at the island of Santa Anna in October, 1882, my attention was directed by Mr. William Macdonald and Mr. Heughan to a curious vegetable substance, not unlike a yam in appearance, which is found lying loose on the soil. The specimens I obtained varied between one and five pounds in weight, but much larger examples have been obtained. The interior of the substance is white in colour, and sometimes has a waxy look. A large slab which had been whittled out by a native resembled a cake of compressed flour. There were many curious speculations as to the nature of these growths. In the estimation of the inhabitants of the island, they are poisonous, and they have received from them the name of “testes diaboli;” but I could gather but little information from the natives on the subject except to the effect that they are also commonly found on St. Christoval.[438] However, some time later I was informed by Mr. Stephens of Ugi that some mushroom-like growths were borne by a specimen that he kept, which after a few weeks fell away. I subsequently gave some of these singular masses to Mr. Charles Moore, the Director of the Sydney Botanic Gardens.
[438] In the event of it proving edible, Mr. Heughan cooked a specimen, but only a tasteless substance resulted.
Three years passed away and I had almost forgotten about the matter, when I accidentally came upon some substances, closely resembling these masses, which are exhibited in the Botanical Department of the British Museum. They are labelled Pachyma Cocos (Fries) from China. On my asking Mr. George Murray concerning their nature, I was pleased to learn that he had been taking a special interest in these growths; and he showed me a specimen obtained by the Rev. Mr. Whitmee in Samoa, from which a funnel-shaped fungus, about six inches high, was growing. This specimen was very similar to those of the Solomon Islands.
Very recently, Mr. G. Murray has embodied the results of his investigations of these growths in a short paper read before the Linnean Society, in which Mr. Whitmee’s specimen is figured (Trans. Linn. Soc., 2nd ser. Bot., vol. ii., part 11). From this source I learn that Rumphius was the first to describe these tuberous masses and their associated fungi from Amboina. The former, which he named Tuber regium, were stated to afford remedies useful in diarrhœa, fevers, &c. The fungi were said to shoot out from them during showers of warm rain on a fine day, or when there was thunder in the air. From the description and illustration given by Rumphius, Mr. Fries regarded the growth as a fungus belonging to the genus Lentinus, springing from a Pachyma (of which the Indian Bread of North America, Pachyma cocos, is an example). Strange to say, however, these tubers, which are found also in China and other parts of the world, have never been found with a fungus attached since the time of Rumphius. Mr. Whitmee’s specimen, therefore, had considerable interest. It is shown by Mr. Murray to correspond strikingly with Tuber regium and to have the structure of a true “sclerotium” (not of Pachyma), with a fungus of a species of Lentinus growing from it. All the facts go to prove that the fungus and the tuberous mass do not form part of the same growth, but are distinct organisms. A spore having germinated on the surface of the mass, its mycelium penetrates the interior, and becoming perennial, produces successive crops of fungi.
Residents in the Indian Archipelago and in the Pacific Islands might throw considerable light on the subject of these growths by careful notes and collections. It is important to discover the origin of the tuberous mass which becomes, so to speak, a convenient nidus for the fungus. How do such masses perpetuate themselves? A considerable number should be kept under observation, and the mode of appearance of the fungus carefully noticed. Experiments might be made with the spores of the fungus by dusting them over the surface of the masses. Such notes and collections should be forwarded to Mr. Murray, at the British Museum of Natural History.