336 THE TONGA PLANT (ePIPREMNUM MIRABILE, SCHOTt). 



members are more noted for their doubtful and poisonous qualities 

 than for their good and useful ones. 



The following is a description of the Tonga plant, chiefly com- 

 piled from Mr. Bull's specimen, together with full synonymy : — 



Epipremnum mirabile, Schott, ' Genera Aroidearum,' p. 79. — 

 Stem chmbing, in juvenile i^lants slender, about 1-lOth inch thick, in 

 adult flowering plants about 1 inch thick, clothed towards the apex 

 with the persistent fibrous remains of the scale-leaves,''' Smallest 

 leaves of juvenile plants, with a petiole 1^-1^ inch long, vagiuate 

 for about half its length, and a lamina 1-1-| inch long, f-1 inch 

 broad, obliquely cordate-ovate, acute or shortly cuspidate, entire, 

 without perforations ; as the plant gets older the petioles elongate 

 and the lamina increases in size, becoming obliquely oblong-ovate, 

 or lanceolate-oblong, acute or shortly acuminate, with small perfo- 

 rations or pellucid spots, mostly arranged along the sides of the 

 midrib ; from being quite entire these gradually pass to a more and 

 more pinnatifidly segmented form, until the adult stage is reached. 

 Petioles of adult leaves stout, 8-15 inches long, including the 1-1|- 

 inch long geniculus, convex on the back, channelled down the face, 

 and vaginate nearly up to the geniculus. Lamina 14-20 inches 

 long, 7-12 inches broad, shining dark green, oblong or elliptic- 

 oblong in outline, acute, cordate or subcordate at the base, more or 

 less obhque, pinnatisect nearly to the midrib, segments varying 

 from 4-10 in number on each side, but more numerous on one side 

 than on the other, straight or somewhat falcate, all except the 

 lowest of about equal breadth throughout their length (usually 1-2 

 inches broad), apex truncate or somewhat convexly truncate, the 

 upper edge produced into an acuminate point, the terminal lobe 

 more or less diamond- shaped, much larger than the rest. Primary 

 lateral nerves 2-3 in each of the basal segments, one only up the 

 centre of the other segments, or sometimes two or more, when two 

 or more segments are united into one, spreading, running out 

 straight almost to the margin, and then curved into the acuminate 

 point ; midrib and veins rather impressed above, very prominent 

 and rounded beneath. Peduncle 4-6 inches long, terete, Spathe 

 4-4|- inches long, ovate, boat-shaped, shortly cuspidate-acute, green 

 outside, puce-coloured inside. Spadix sessile, much shorter than 

 the spathe, cylindric obtuse, green, about two -thirds of an inch 

 thick. Ovaries cuneate, sub-hexagonal, truncate, one-celled with a 

 septiform placenta projecting one-third across the cell, bearing two 

 ovules, one on either side at its base (rarely only one ovule) ; 

 stigma sessile, linear. Schott, ' Prodromus Aroidearum,' p. 388! ; 

 Engler, in DC. ' Monog. Phanerog.,' ii., p. 249!; RhapJiidophora 

 lacera, Hasskarl, in ' Tijdschrift voor Natuurlijke Geschiedenis en 



• If I understand the descriptions aright of the various authors who have 

 describe'd this plant, I think they mean to imply that these persistent fibres are 

 the remains of the vagina of the foliage- leaves; but this is not the case, for they 

 are the remains of cataphyllary leaves, which are not developed until the plant 

 tiowers, anil accompany a change from a monopodial to a sympodial mode 

 of growth of the stem, exactly as occurs in Fhllodendron, for example, F 

 Slimii. 



