SPERMATOPHYTES 
229 
uted throughout the tropics of both hemispheres. Gnetales have always 
attracted attention from the fact that in certain characters they resemble 
angiosperms more nearly than do the other gymnosperms. 
FIG. 517. Tumboa, showing the heavy conical body and the two-lobed crown bear- 
ing two broad parallel-veined leaves (in the photograph split into shreds) and strobilus- 
bearing branches. 
Sporophyte. The species of Ephedra are straggling shrubs, with 
long-jointed and fluted green stems, and scalelike opposite leaves form- 
ing at each joint a two-toothed sheath 
(figs. 511, 512, 975). Tumboa has a 
huge, woody, turnip-shaped body, 
whose crown bears a single pair of 
elongated , strap-shaped, parallel- veined, 
and persistent leaves (fig. 517). The 
species of Gnetum are small trees or 
woody twiners with leathery, net- 
veined, opposite leaves, resembling 
those of dicotyledons (fig. 522). It 
will be observed that a constant char- 
acter of the group is the cyclic (op- 
posite) leaves, a feature found among 
Coniferales only in the Cupressineae. 
519 
FIGS. 518, 519. Ovulate(sr8)and 
staminate (519) strobili of Tumboa. 
518, after LE MAIOUT and DE- 
Vascular anatomy. It is in their CAISNE; 5 19, after HOOKER. 
vascular anatomy that the Gnetales 
show a striking angiosperm character. The secondary wood does not 
consist exclusively of tracheids with bordered pits, as in the other gym- 
