Ay ea OXXVIII. GNETACER (Pearson). [ Ephedra. 
Orver CXXVIU. GNETACESS. 
(By H. H. W. Pearson.) 
Dicecious or moneecious. Florets (flowers) diclinous or pseudo- 
bisexual, few or many in axillary, rarely terminal, unisexual or 
bisexual spikes. Male floret (pseudo-bisexual in Welwitschia) : 
Envelope formed of one pair or two decussating pairs of scales, free 
or united. Stamens 1-8 with the anthers sessile or subsessile on the 
summit of a stout central axis or (in Welwitschia) 6 with the filaments 
connate at the base around a central superior barren ovule. Female 
floret : Envelope an ovary-like utricle. Ovule naked, erect, ortho- 
tropous with a single integument produced into an elongated tubular 
micropyle and protruding through the orifice of the utricle, with or with- 
out an aril. Seed albuminous, enclosed at maturity in the hardened 
utricle which is either differentiated into a fleshy outer and a hard 
inner layer, or entirely coriaceous and sometimes (Welwitschia) pro- 
duced laterally into 2 wings. Embryo straight with 2, rarely 3, 
cotyledons.—Erect or scandent virgate or leafy shrubs, trees or woody 
climbers or (in Welwitschia) a woody plant of unique form consisting 
of a stout tuberous hypocotyl and an early arrested depressed stem 
apex, with true vessels in the secondary wood, without resin canals. 
Foliage leaves 2 or more, rarely in whorls of 3, opposite, simple. 
Spikes at the time of pollination greenish or yellowish, rarely vividly 
coloured (Welwitschia). Seeds with their envelopes more or less 
enclosed in dry or fleshy cones or exposed and drupe-like (Ginetum). 
Genera 3; species 50-60, mainly in the tropics and subtropics of both hemi- 
spheres. 
The group as defined above covers an extremely wide range of generic 
characters ; when these are more completely known it will perhaps be necessary 
to subdivide it into at least two Natural Orders. 
Trine I. EPHEDROIDEA.— Leaves usually all, or all but those of the seedling, 
reduced to scales. Stems longitudinally grooved or striated. Embryo not 
developing a “ feeder” during germination. 
Only Tropical African genus ... 1. EPHEDRA. 
Trise Il. GNETOIDEA!.—Leaves large. Stems not longitudinally grooved. 
Embryo developing a “ feeder ’’ during germination. 
Trees, shrubs or lianes with more than one pair of 
foliage leaves. Pollen’spherical .. ies «.. 2, GNETUM. 
Plant body mainly a much thickened woody hypo- 
cotyl with a single pair of foliage leaves. Pollen 
ellipsoid ce She sae ape 3. WELWITSCHIA. 
1, EPHEDRA, Linn. ; Benth. et Hook. f. Gen. Pl. iii. 418. 
Usually dicecious. Florets unisexual. Male florets in 2-12 pairs, 
crowded in short rounded (rarely angular) spikes, in the axils of 
