GNETACEJE. .5j 



foliage-leaves (probably the cotyledons) of immense size. They are extended on 

 the ground and become divided into strips as they become old ; the stem remains 

 short, rising only slightly above the ground, and is broad above with a furrow 

 across the top, while it is tuberous below, and passes into the tap-root \ 



The Flowers of Gnetaceae are unisexual, and are arranged in dioecious 

 (Ephedra) or monoecious inflorescences ; the inflorescence has a well-defined form, 

 and in Ephedra and Gnetum springs from the axils of the opposite leaves. The 

 male flower of these genera consists of a small bifid perianth, in the middle of 

 which rises a staminal column, which in Gnetum is bifurcate above and bears two 

 bilocular anthers, in Ephedra a larger number crowded into a head. The female 

 flower of Gnetum (Eichler, in Flora 1863, p. 463), like that of Ephedra, also possesses 

 a perianth, flask-shaped in the former, obscurely trigonous in the latter genus ; it 

 envelopes a central ovule possessing in the case of Ephedra one integument, in 

 that of Gnetum two, the inner of which is elongated like a style. The more exact 

 morphology of these flowers is still doubtful. The endosperm of Ephedra is said 

 by Schacht to produce only one archegonium, and the contents of the longish 

 pollen-grain to divide like those of the-Abietineae. In Gnetum the inflorescence, 

 which springs from the axil of the foliage-leaves, consists of a jointed axis with 

 verticillate leaves, in the axils of which the flowers, male and female, are agglo- 

 merated. The inflorescence of Welwitschia^ is a dichotomously branched cyme 



' For a full description of this remarkable plant see J. D. Hooker in Trans. Linn. Soc. 

 vol. XXIV. 



^ [According to Professor W. R. M^Nab, ' The cones of Welwitschia consist of numerous 

 opposite and decussate bracts, with a sessile flower in the axil of each of the bracts. The per- 

 fect flowers in the male cone consist of two outer perianth leaves (calyx) placed right and left, 

 two inner ones (corolla) placed anteriorly and posteriorly, six stamens united below, and two 

 carpels anterior and posterior, the conical end of the axis projecting as a rudimentary axile ovule 

 surrounded by the two carpels. The outer parts of the perianth are first developed, appearing as 

 two shoulders at the very base of the young floral branch. The flower next in age has the floral 

 axis more elongated, the outer parts of the perianth larger, and a distinct swelling is visible above the 

 outer parts. These swellings are anterior and posterior, and much larger than the outer parts. 

 Above the inner parts of the perianth the axis is expanded, and contracts near the rounded apex. 

 The expanded portions are superposed on the outer lateral parts of the perianth, and are the two 

 primordial staminal cushions. These cushions are semilunar, and in the earlier stages show no trace 

 of division into three. At this stage the parts of the perianth rapidly enlarge and cover in the 

 central parts of the flower. A projection now forms anteriorly and posteriorly, the first indication 

 of the two carpels. The next' stage shows the two staminal cushions each forming three elevations, 

 the central one larger than the two lateral ones. The six stamens are thus produced by the branching of 

 two primordial stamens. In the next stage the carpels elongate and cover in the punctum vegetationis, 

 ultimately developing the peculiar style and stigma-like process. The axis elongates slowly and 

 forms a conical projection which is undoubtedly a rudimentary axile ovule, but it never shows any 

 appearance of an embryo-sac' 



In the female flowers, which are produced in different cones from the male flowers, the develop- 

 ment is very different. A very short stalk is developed in the female, which is wanting in the male ; 

 then two shoulders are developed exactly like the two outer parts of the perianth in the male flower, 

 to which Dr. Hooker considered them to be equivalent. Judging from the construction of the male 

 flower. Professor McNab was disposed to accept this view ; but with hesitation, as he could not 

 account for the stalk-like process. Strasburger however concludes that they are carpels, and in 

 that M<=Nab quite concurs. Above the carpels the axis elongates slightly, and a ring is formed 

 surrounding the punctum vegetationis. This ring is the ovular integument. Comparing the two 

 flowers, it will be seen that in the male there are four series ofpaits, in the female the three outer 



