2 DR. J. D. HOOKER ON WELWITSCHIA. 
Before describing in detail the structure of this plant, and See 
anomalies, I shall give a brief general account of its appearance and en. it 
partly from the descriptions of its discoverer, and partly from the sp 
imself and others. a : : 
nth Panel is a woody plant, said to attain a century in duration, aes 
obeonic trunk about 2 feet long, of which a few inches rise above the on ee oa 
the appearance of a flat, two-lobed, depressed mass, sometimes (accor on nts 
Welwitsch) attaining 14 feet in circumference (!), and looking like a roun ae : 
When full grown, it is dark brown, hard, and cracked over the whole surface (muel ce 
the burnt crust of a loaf of bread); the lower portion forms a stout tap-root, buried in 
the soil, and branching downwards at the end. From deep grooves in the circumference 
of the depressed mass two enormous leaves are given off, each 6 feet long when full- 
grown, one corresponding to each lobe: these are quite flat, linear, very ope 
and split to the base into innumerable thongs that lie curling upon the surface of t e 
soil. Its discoverer describes these same two leaves as being present from the earliest 
condition of the plant, and assures me that they are in fact developed from the two coty- 
ledons of the seed, and are persistent, being replaced by no others. From the circum- 
ference of the tabular mass, above but close to the insertion of the leaves, spring stout 
dichotomously branched cymes, nearly a foot high, bearing small erect scarlet cones, 
which eventually become oblong and attain the size of those of the common spruce fir. The 
scales of the cones are very closely imbricated, and contain when young and still very 
small, solitary flowers, which in some cones are hermaphrodite (structurally but not 
functionally), in others female. The hermaphrodite flower consists of a perianth of four 
pieces, six monadelphous stamens with globose 8-locular anthers, surrounding a central 
ovule, the integument of which is produced into a styliform sigmoid tube, terminated by 
a discoid apex. The female flower consists of a solitary erect ovule contained in a com- 
pressed utricular perianth. The mature cone is tetragonous, and contains a broadly 
winged fruit in each scale. Its discoverer observes that the whole plant exudes a resin, 
and that it is called “ Tumbo” by the natives, whence he suggests that it may bear the 
generic name of ‘*Zwmboa;’’ but this he withdrew at my suggestion, for reasons which 
I shall presently give. It inhabits the elevated sandy plateau near Cape Negro © 
(lat. 15° 40’ S.), on the S.W. coast of Africa. 
In his letter to Sir William Hooker, Dr. Welwitsch says nothing definite as to the 
affinities of this plant, but compares the stigma (or, as I consider it, the apex of the 
ovular integument) to that of certain Proteacee, the cones to those of certain Abietinee, 
the resin to that of Conifere, and the fibrous substance in the integument of the seed to 
that of Casuarina. — 
After his arrival in Portugal in 1861, Dr. Welwitsch addressed to M. DeCandolle at 
Geneva a very interesting letter on the vegetation of Benguela and the neighbouring 
parts of Africa, in which the “Tumbo” was again described. In this letter, which was 
dated Lisbon, April 20, 1861, and communicated to the « Bibliothéque Universelle de 
Genéve,’ Dr. Welwitsch makes the following remarks :—* This is assuredly one of the 
most extraordinary plants that exist in intertropical Africa; and notwithstanding certain 
