I 



MR. W. GRIFFITH ON THE GENUS GNETUM. 307 



says, after alluding to his want of success in tracing the particles contained in poUen- 

 grains through the tissue of the style, " Even in those families in which I have sup- 

 posed the ovvilum to be naked, namely Cycadeee and Coniferce, I am iaclined to think 

 that the direct action of these particles, or of the pollen containing them, is exerted 

 rather on the orifice of the proper membrane than on the apex of the included nucleus ; 

 — an opinion which is in part founded on the partial withering confined to one side of 

 the orifice of that membrane in the Larch, — an appearance which I have remarked for 

 several years." It is, however, most probable that, from the late rapid increase of our 

 knowledge of the process of fecundation in Phsenogamous plants, chiefly indeed owing to 

 the beautiful observations of this distinguished botanist, the opinion above cited has been 

 modified by its author. 



With regard to the two principal objections urged by Dr. Brown * against the opinion 

 of the female flower of Cycadeee and Conifer cb being a naked pistiUum, the first, viz. that 

 arising " from the perforation of the pistUlum, and the exposm*e of that point of the 

 ovulum where the embryo is formed to the direct action of the pollen," still holds good. 

 The second, viz. the too great simplicity of structure of the supposed ovulum, I look 

 upon as in a great measure destroyed by the reduction of the usual number of the 

 constituent pai-ts of this organ in Loranthaeece\ . 



Respecting the male floAver, I have to add, that Linnaeus was correct in referring the 

 genus to Moncecia Monadelphia. Roxburgh adopts the same view in his MS. Synopsis ; 

 but in his ' Flora Indica ' he refers it to the Moncecia Monandria. The correctness of 

 Linnseus's view is proved by the fact that there are two filaments at an early period, or at 

 least that their tmion is only partial, and by the number, situation, and distribution of 

 the vascular fascicles. 



Gnetace^, Lindley, in Bot. Register, vol. vii. N. S. 1. 1686, sub Garrya. 



Diagnosis. — Planta gymnospermse, dicotyledoneae, aquosje. Rami articulati. Folia opposita, indivisa, 

 venia anastomosantibus reticulata. 



Char, essentialis. — Flores monoici, in spicis amentiformibus verticillatim dispositi; verticillus singu- 

 lus involucro aanulato integerrimo (rarius obsolete) sufFultus distans. Masculi pluriseriati, in verti- 

 cillis inferius dispositi. Perianthium tubulosum, inverse subulato-conicum fere cuneatum, mutua 

 pressione angulatum, apice planiusculo vel depresso, rima transversa dehiscens, carnosum. Fila- 

 mentum unicum, monadelphum (e 2 nempe coalitis formatum), hypogynum, clavatum, per anthesin 

 per rimam transversam exsertum. .^?i/^er<» duae, uniloculares, basibus affixae, erectae; loculi ora- 

 nino discreti longitudinaliter et centraliter secus latus utrumque dehiscentes. Pollen simplex, laeve, 

 oblongum. — Fceminei in verticillis superius dispositi, 1- vel 2-seriati. Perianthium nullum. Ovuta 

 ovata, sajpe obliqua, transverse sita, orthotropa. (Junius.) Tegumenta bina ; exterius fibroso-cellii- 

 losum, interius cellulosum, ssepius inclusum, utrumque apice apertum. Nucleus cellulosus tegu- 

 mento conformis, liber. (Maturius.) Tegumenta terna ; tertium novumque nucleum cingens, supra 

 ejus apicem in tubum cylindricum styliformem longe exsertum ore dilatato marginibusque laci- 

 niatis productum. Fructus (semen maturum) omnino exsertus, sessilis vel stipitatus, drupaceus, 

 laevis vel lepidotus, ovatus, indehiscens. Sarcocarpium extus cellulosum, intus fibrosum (fibrae 

 utrinque acutae pungentes, diametro magno, coloratae), apice perforatum. Endocarpium fibrosum, 

 fragile, subosseum, sarcocarpio adnatum, e fibris longitudinaliter cellulisque transverse sitis 

 * ' Kinffia,' p. 28. t Sec my Paper on this subject. 



2 s 2 



