GYNOSCIUM OF GYMNOSPERMS. 269 



in the extant vegetable kingdom b}- three (or four) groups or 

 orders, two of them small, and one comparatively ample and of 

 wide distribution ; and all are so strikingly different from each 

 other that they cannot be illustrated b} r a common description. 

 The largest order, Coniferae, is familiar, and contains a good 

 share of the most important forest trees of temperate climates. 

 The smallest, Gnetaceae, chiefly tropical or of warm regions, 

 lies between Gymnosperms and common Dicotyledons. The 

 third, Cycadaceae, is most remote from them, and as much so 

 from Monocotyledons, except that it imitates Palms, as it 

 also does the Tree-Ferns, in habit, both as to stem and foli- 

 age. The particular morphology of Gymnosperms would re- 

 quire for its illustration copious details and the history of various 

 conflicting hypotheses. It must be relegated to the special 

 morphology of the natural orders, premising, however, a brief 

 sketch of the general floral structure. 1 



505. In Gnetacese, Gymnosperms and Angiosperms almost 

 come together. The flowers have a perianth (diphyllous or 

 tetr aphyllous) ; the stamens have a distinct filament and anther ; 

 and the gynrecium is a sac (presumably of two carpophylls) 

 open at the top and filled at bottom by a single ovule of the 

 simplest kind, i. e. consisting of a nucleus destitute of coats. 

 This pistillary body is attenuated and prolonged above the ovule 

 into a style-shaped tube, with open and commonly two-cleft 

 orifice. In the almost hermaphrodite sterile flower of Wei witschia, 

 this takes the form of a much dilated stigma, which is even beset 

 with seeming stigmatic papillae. If only the pollen were here 

 to grow forth into pollen-tubes (with or without a closing of the 

 tube) , angiospermy would be attained. But, in fact, the pollen- 

 grains bodily reach the ovule itself through the tube, fertilizing 

 it directly.' 2 This interesting group of plants consists of the 



1 References to the literature of gymnospermy and to the steps of the 

 prolonged controversy over it, also the points of morphology still in part 

 unsettled, need not here be given. The history and the idea of gymnospermy 

 began with Robert Brown's paper on Kingia, " with Observations .... on 

 the Female Flower of Cycadeae and Coniferae," read before the Linnean 

 Society in the year 1825, and published in King's Voyage in 1827 ; and the 

 bibliography down to a recent date is given by Eichler in Flora Brasiliensis, 

 Gymnospermia, iv. 435, and in Bliithendiagramme, i. 55-69; also ii. preface x.. 

 See also Alph. DeCandolle, Prodr. xvi.- 345, 524. In this volume, the late 

 Prof. Parlatore adhered to the ancient ideas in his monograph of the Coniferae. 



2 The view here implicitly adopted is that of Beccari, founded on the study 

 of Gnetum, and published in Nuovo Giornale Botanico Italiano, ix. 1877. 

 It was before nearly or quite reached in successive steps, by J. D. Hooker, 

 in his classical memoir on Welwitschia, in Trans. Linn. Soc. xxiv.; Stras- 

 burger, Die Coniferen und die Gnetaceen, 1872; and W. R. McNab, in 

 Trans. Linn. Soc. xxviii. 1872. 



