GNETALES— EPHED R A 



369 



hunting through a large patch, a monoecious individual can generally 

 be found, and in E. foliata they are rather common. Staminate and 

 ovulate strobili are found on the same plant, and Land found bi- 

 sporangiate flowers in E. trifurca. Wettstein^^" found similar 

 flowers in E. campylopoda, and others have reported them for other 

 species (fig. 350). When both sexes are in the same strobilus, the 

 staminate flowers are below and the 

 ovulate at the top, as in the bisporangi- 

 ate strobiU already described for Picea 

 and other conifers. 



The staminate strobilus. — The stami- 

 nate strobili are in whorls of 2, 3, or 4 at 

 the nodes of the small green branches. 

 The whorled condition of the leaves of 

 the vegetative shoot is also present in 

 the floral axis. There is no doubt that the 

 staminate structure is a compound stro- 

 bilus, a feature which, with vessels in the 

 secondary wood, separates the Gnetales 

 from the rest of the gymnosperms. 



The male strobilus consists of a short 

 axillary shoot, bearing 2-8 opposite 

 pairs of bracts, of which the lower one or two pairs are sterile, 

 while the rest bear solitary flowers (fig. 351). In the axil of a 

 fertile bract is a shoot, bearing two thin, opposite scales, which have 

 been interpreted as a perianth. Between these scales the axis is pro- 

 longed, and bears the microsporangia at its top. Whether the scales 

 should be called a perianth, is doubtful; but it is certain that they 

 are reduced opposite leaves, more or less united at the base, covering 

 the axis before the elongation which pushes the stamens out into a 

 favorable position for shedding their pollen. 



The structure bearing the two scales at the base, and the sporangia 

 at the top, has been called a "sporangiophore," a good name because 

 it is efficient for reference, like placenta and receptacle, and is just 

 as noncommittal. In some species one or more — usually more — 

 sporangia are sessile at the top of the sporangiophore. In Ephedra 

 trifurca there are 5 or 6 sporangia, and each one is borne on a 

 filament, which may be called a sporophyll, just as reasonable 



Fig. 350. — Ephedra campylo- 

 poda: hisporangia. strobilus; X7. 

 — After Wettstein.^'" 



