G YMNOSPER MS. io:- 



the micropyle, its plumule towards the base of the seed. The first leaves which 

 the embryonal stem produces stand in a whorl, consisting generally of two opposite, 

 but not unfrequently of three, four, six, nine, or more members. The radicle 

 does not project through the split testa of the seed until the period of germination ; 

 the bud which is formed between the Cotyledons or first leaves at the apex of the 

 stem is forced out by their elongation, the cotyledons still remaining concealed 

 in the embryo, and remaining in it until its food-materials have been completely 

 consumed by the embryo. Sometimes they remain concealed there as organs 

 which have become useless; but in Coniferae they are drawn out by the elonga- 

 tion of the embryonal stem and brought above the surface of the ground, where 

 they unfold as the first foliage-leaves. The cotyledons of Coniferse become green 

 even within the seed in complete darkness, the formation of chlorophyll taking 

 place, as in Ferns, without the assistance of light. It is not known whether 

 the same thing occurs also in Cycadeae and Gnetaceae. The young plant, freed 

 from the seed, consists of an erect stem, passing below insensibly into the verti- 

 cally descending tap-root, from which numerous secondary roots soon proceed 

 in acropetal order, usually forming finally a powerful root-system. The embryonal 

 stem grows vertically uj) wards, and is usually not only unlimited in its growth, 

 but is much stouter than all the lateral shoots, even when these are formed in 

 abundance, as is the case with Coniferae. In the remarkable Gnetaceous Wel- 

 witschia the apical growth however altogether ceases at a very early period, and 

 even the production of new leafy shoots is suppressed, as is usually the case also 

 in Cycadeae. 



The Flowers are usually developed on small lateral shoots, often of a high order 

 of ramification; terminal flowers occur on the primary stem only in the Cycadeae 

 (and in them not exclusively). They are always diclinous; the plants themselves 

 monoecious or dioecious. The male flower consists of a slender axis usually greatly 

 elongated, on which the staminal leaves are arranged in large numbers usually 

 spirally or in whorls. The female flowers are remarkably different in their external 

 appearance, and usually very unlike those of Angiosperms. A kind of perianth of 

 rather delicate leaves occurs only in Gnetaceae; in Coniferae and Cycadeae it is 

 wanting or is replaced by scales. But what makes the female flowers peculiarly 

 strange, independently of the absence of an ovary, is the elongation of the floral 

 axis, on which the foliar structures are placed not in concentric circles as in Angio- 

 sperms, but in a distinctly ascending spiral arrangement, or in alternating whorls 

 when they are numerous. When only a few ovules are produced on a naked 

 or small-leaved inflorescence, as in Podocarpus and Salisburia, the last trace of 

 resemblance in habit to the flowers of Angiosperms ceases. But to clearly under- 

 stand the matter it is only necessary to retain distinctly in mind the definition of 

 a flower, viz. an axis furnished with sexual organs. 



On the formation of tissue in Gymnosperms see the remarks at the conclusion of 

 the description of the whole class. 



F f 2 



