GNETACEM. 5^9 



height, rising above the insertion of the two enormous leaves on the periphery of the 

 broad apex of the stem. The branches of the inflorescence are terete and jointed, 

 spring from the axils of the bracts, and bear upright longish cylindrical cones ; these 

 are furnished with from seventy to ninety broadly ovate scale-leaves standing closely 

 one above another in four rows, a single flower being seated in each axil, male and 

 female in different cones. The male flowers are pseudo-hermaphrodite, and possess 

 a perianth consisting of two pairs of decussate leaves ; the lower ones are entirely 

 free, sickle-shaped and pointed, the upper ones broadly spathulate and coherent at 

 their base into a compressed tube. Within this tube are six stamens, monadelphous 

 at the base, with cylindrical filaments and terminal spherical bilocular anthers, which 

 dehisce above the apex with a three-armed fissure ; the pollen-grains are simple (?) 

 and elliptic. The centre of the flower encloses a single erect orthotropous sessile 

 ovule with broad base, and with no other investment than a simple integument, 

 which is drawn out into a style-like tube with a margin expanded in a discoid 

 manner ; the nucellus, however, has no embryo-sac, or is sterile. In the female 

 flowers the perianth is tubular, greatly compressed, somewhat winged, and altogether 

 undivided; there is no indication of any male organ; the ovule (in this case of 

 course possessing an embryo-sac) is entirely enclosed in the perianth, and is similar 

 in its external form to that of the male flower, but with this diff'erence, that the elon- 

 gated point of the integument is only simply slit, not expanded into the form of a 

 plated When ripe the cone is about two inches long and of a scarlet colour; the 

 scales are persistent ; the perianth enlarges considerably and becomes broadly 

 winged ; its cavity is narrowed above into a narrow canal, through which the apex 

 of the integument passes. The seed is of the same form as the unfertilised ovule, 

 and contains abundant endosperm, in the axis of which lies the dicotyledonous 

 embryo ; the embryo is thick at the radicular end, and is there attached to the very 

 long spirally-coiled suspensor. The formation of endosperm commences in the 

 embryo-sac before fertilisation ; archegonia without necks, consisting, that is, only of 

 oospheres, are formed which grow out of the embryo-sac to the number of from 

 twenty to sixty, and penetrate into the canal-like cavity of the nucellus, there they 

 are fertilised by the pollen-tubes which have grown to meet them. [After fertilisation, 

 the oospore elongates into a tube, a portion of which is cut off" by a wall near its 

 lower end. This cell at once divides into four, placed crosswise. These cells mul- 

 tiply by division, so that a group of cells is formed which, for the most part, constitute 

 the embryo ; the marginal cells of the group grow out into long tubes, the so-called 

 * embryonal tubes.' Although from two to eight archegonia are fertiUsed only one 

 embryo is developed. 



The development of the ovule and of the embryo-sac has been studied by 

 Strasburger (Angiospermen und Gymnospermen) in Gnetum Gnemon. Groups of 



posterior, while in the female they are lateral. This is to be explained by the fact that the carpels 

 are here the first leaves of a branch, and that it is very rare (except in grasses) that the first leaves of 

 a shoot are anterior or posterior, and not lateral. The ovular integument of the female flower is 

 wanting in the male. While therefore the male flower is complex, the female is remarkably simple. 



For further details see Transactions of the Linnean Society, 1873, vol. XXVIII. pp. 507-512. 

 On the general Morphology and Histology of Wehviischia see Bower, Quart. Journ. Micr. Sci. 1881. 



^ [Strasburger {loc. cit.) now regards the ' perianth ' as an outer integument.] 



M m 



