526 PIIA NER GA MS. 



oospore; but Picra imJgaris in this group resembles /?wiperus in the preceding, in 

 that only a single embryo is developed. In Taxus haccafa the rudiment of the 

 embryo consists of two or three tiers of cells, the upper of which elongate to form 

 the suspensor : the lower tier consists of from four to six cells, one only of which 

 gives rise to the embryo : the suspensors do not become isolated (Fig. 354). In 

 Salisbun'a, according to Strasburger, no suspensor is formed : the cells which are 

 formed in the oospore, after fertilisation, form a coherent mass of tissue, which 

 increases by cell-division, and this constitutes the embryo. 



It appears, therefore, that several embryos can be produced from one oospore ; 

 the number within a single endosperm being increased by the simultaneous fertilisation 

 of severa larchegonia. Polyembryony, which is rare among Angiosperms (see infra), 

 is thus the typical condition among Conifers and generally among Gymnosperms, 

 but only in the very earliest stage ; for usually only one of the rudiments developes 

 into a vigorous embryo, such as has already been described. During its development 

 the endosperm also continues to grow vigorously; its cells become filled with reserves 

 of food-material (fat and albuminoids) ; the embryo-sac which surrounds it grows at 

 the same time, and finally supplants the tissue of the nucellus, the tissue of the in- 

 tegument hardening at the same time into the testa. In Salisburia, however, an 

 outer strong layer of tissue forms the pulpy envelope which causes the seed to 

 resemble a drupe. The elongated cells of the suspensor usually disappear during 

 these processes, but according to Schacht are permanent in Larix. 



During the period that the seeds are ripening, the carpels and the placentae 

 also continue to grow and to undergo changes in texture. In Taxus a red aril, 

 which afterwards becomes pulpy, grows round the ripening seed (Fig. 348 m)\ in 

 Podocarpus the part of the floral axis that bears the scales and the seeds, and which 

 was already considerably swollen, becomes fleshy; in Juniperus and Sahina the 

 carpels themselves form the blue 'berry' which envelopes the seeds: in most other 

 Cupressineae the carpels grow, close up laterally and become woody ; and the same 

 occurs in those Abietineae which are without bracts (in respect to Cunninghamia, 

 vide supra) ; while in Pinus, Abies, C^drus, and Larix, it is the placental scales 

 which after fertilisation grow vigorously, outstripping in their growth the true carpels 

 (bracts), become woody, and form the mature cone. In all these cases (except 

 Podocarpus, Salisburia, and Taxus), the seed is closely and firmly enclosed during 

 ripening by the carpels or placental scales ; it ripens within the fruit, the parts of 

 which do not again separate or become detached (as in Abies pec tinata) in order to 

 allow of the escape of the seeds until they are completely ripe. 



So long as we are still in doubt as to the nature of the female flowers of various 

 genera, the systematic arrangement of the Goniferae can only be considered as provi- 

 sional; Endlicher (Synopsis Coniferarum, 1847) distinguishes the following families: — 



Family r. Cupressineaa. Leaves, including those of the flowers, opposite or 

 verticillate (in Division e single); flowers monoecious or dioecious; stamens terminating 

 in a shield-like expansion bearing pollen-sacs in twos or threes or larger numbers; 

 female flower consisting of alternate whorls of carpels, bearing at their base or on their 

 inner surface two or a larger number of erect ovules (in Juniperus communis the ovules 

 are alternate with the three carpels on the floral axis) ; embryo with two, rarely three 

 or nine cotyledons. 



