[Read before the Wellington Philosophical Society, 25th September 1895.]
The remarkable monotypic genus Dactylanthus constitutes the fourth tribe of Balanophoreæ, an order of root-parasites most of which have a very local distribution. Dactylanthus, the “pua-reinga” of the Maoris, was originally discovered about 1857 by the Rev. Richard Taylor, growing on the roots
of Pittosporum, Fagus, and other trees near the head of the Whanganui River, at an estimated altitude of 4,000ft. Although the plant grows over a wide area it is remarkably local, so that it is desirable to record the localities in which it has been observed. After its original discovery it does not appear to have been noticed by any collector until April, 1869, when I had the good fortune to discover it, at an altitude of 1,800ft. or 1,900ft., on the Thames Goldfield, where it was parasitic on the roots of Schefflera digitata and Coprosma grandifolia; but, owing to the advanced period of the summer, the specimens were so much decayed that only the rhizomes were in a fit state for removal: several of these were deposited in the Colonial Museum.* It was decidedly rare, and was limited to a very small area. Although I paid several visits to the habitat in subsequent years, the complete destruction of the arboreal vegetation by mining operations appeared to have killed the parasite; but I believe it has been recently collected by Mr. Cheeseman, either in the habitat where it was first observed by me or some other in its near vicinity. It was next observed by Mr. J. P. Marshall on the banks of the Mohanga River, Rangitikei, and he kindly presented me with a male specimen in 1878. In 1887 it was collected by Mr. W. H. Skinner in the Taranaki District, but I am ignorant of the exact locality, although Mr. Skinner generously forwarded his specimen for my herbarium. It is the only female specimen that I have seen; the fruits are fully formed, but not ripe. Two small specimens were very kindly given me at a later date by Mr. H. C. Field, who found them in the Whanganui district, but did not state the precise locality. More recently it has been discovered in two localities by Mr. A. Hamilton—at Tarawera, between Taupo and Napier, and at Nuhaka, near the Mahia Peninsula. I am indebted to his goodness for a specimen from the latter habitat. It has also been found in considerable quantity in the forest district between Clyde and Waikaremoana, but the discoverer's name is unknown to me. Lastly, it has recently been found by Mr. H. Hill in the East Cape district, where it evidently grows in great luxuriance, judging from the fine specimen which he has liberally presented to the Colonial Museum; it measures fully 8in. across, and is by far the largest that has come under my notice.
Unhappily, most of the specimens at present obtained are in very poor condition, and enable us to add but little to the excellent description drawn by Sir Joseph Hooker from the material collected by the Rev. R. Taylor. The following notes are written in the hope that they may prove of sufficient
[Footnote] * See Trans. N.Z. Inst., ii. (1869), p. 94.
interest to draw the attention of surveyors, explorers, and settlers in forest districts to one of the most remarkable plants in the flora.
The large rhizome by which it is attached to the roots of its host is usually subterranean, very woody, rounded or amorphous, entire or deeply lobed, and forms a kind of boss, covered on the surface with rounded papillæ, each of which marks the point at which a flowering-stem, was given off. The rhizomes vary greatly in size; some might be completely hidden under a penny-piece, while others are fully 8in. in diameter and 4in. or 5in. thick. When growing on a declivity, roots of the host-plant, from which the soil has been washed away, may be found with the rhizome of the parasite fully exposed, when the position of the flowering-stems is easily made out; but usually the rhizome is buried in the humus amongst which it grows, and only the upper part of the flowering-stems rises above the soil to a greater or less extent.
The flowering-stems are diœcious, from 2in. to 5in. long, somewhat club-shaped, and clothed with brown ovate or oblong imbricating scales, which are evidently fleshy when first developed, but at length become so brittle that they crumble into minute fragments at the slightest touch. The flowers are developed on very short spadices, lin. to 1 ½in. in length at the apex of the stem, and are mostly hidden by the apical scales; the males, which I have not seen, are covered with crowded anthers, and the females with sessile ovaries in great profusion. The ripe fruit is about the size of a radish-seed, and contains a minute undivided embryo, imbedded in granular endosperm. Unhappily, nothing is at present known of the process of germination and development.
Although the dull-brown colour of the flowering-stems renders the portion that appears above ground very inconspicuous, the flowers emit a strong perfume. In a letter to Sir James Hector, Mr. Hill states that he was enabled to discover the plant solely through the “delicious daphne-like fragrance which it emitted,” his attention being first attracted by the perfume.
The large area over which it has already been observed, extending from the Hauraki Gulf to Taranaki and Rangitikei, warrants the idea that a careful search would be rewarded by its discovery in localities where its occurrence has not hitherto been suspected. Any explorer or settler who would communicate a supply of good specimens would render a great service to botanists at large, although there is nothing in the material that has come under my notice to support the idea of there being more than a single species.