GYMNOSPERMA E. CONIFERAE. 33 1 



swollen and club-shaped above. They bear small alternating boat-shaped scales, of 

 which only the two, three or four lower ones are fertile, and bear one macrosporan- 

 gium in their axil. In Gingko the female flowers spring from the axils of scale-leaves 

 or foliage-leaves on short lateral shoots, which produce new rosettes of leaves each 

 year (Fig. 251 A). The single flower consists of an elongated stalk-like axis which 

 bears two lateral macrosporangia immediately beneath its apex, and sometimes a 

 second pair above the first and alternating with it, though one of the two is as a rule 

 abortive. Cephalotaxus has inflorescences with from four to eight decussate pairs of 

 fertile bracts above an elongated basal internode ; in the axil of each bract is a naked 

 shoot which bears a macrosporangium right and left ; in this case therefore the 

 flowers are disposed in spike-like inflorescences. The ovules (macrosporangia) of 

 Taxus are placed singly on diminutive shoots (primary flowering shoots, Fig. 252 D} 

 which spring from the axils of the foliage-leaves of elongated woody shoots, and are 

 furnished with two bracteoles and a number of small imbricated scales. One of the 

 upper scales has an axillary bud, which pushes the growing point of the primary 

 flowering shoot to one side and looks like the continuation of its axis. This secondary 

 shoot bears three decussate pairs of scales and is crowned by the terminal macro- 

 sporangium. Sometimes the scale next below on the primary flowering shoot is 

 also fertile, that is, bears a macrosporangium in its axil ; this indeed is generally the 

 case in Torreya nucifera, which is closely allied to Taxus. If we adhere to the ter- 

 minology hitherto employed, we shall call each macrosporangium in Taxus and 

 Torreya a flower ; but the Taxineae as a rule do not have their flowers in the cone- 

 form which is so characteristic of most of the Coniferae, and the seeds are invested 

 with an aril except in the cases already mentioned. 



It has been stated that the macrosporangia (ovules] of the Coniferae have always 

 one integument and are originally erect and orthotropous ; they retain this position in 

 the Cupressineae, but undergo subsequent changes in this respect in Podocarpus, the 

 Abietineae and other divisions. They consist when fully developed of the central 

 portion of the sporangium (Fig. 259 Nit), a mass of tissue beneath or in which are 

 the sporogenous cells and which here and in the Angiosperms we name after Stras- 

 burger the nucellus, and of the integument^, which usually projects some distance 

 above the nucellus and forms a comparatively broad and long micropylar canal ; 

 through this canal the pollen-grains (microspores) find their way to the apex of the 

 nucellus which is sometimes depressed 2 . Lateral outgrowths of the integument often 

 cause the macrosporangium and subsequently the seed to appear winged, as in 

 Dammara (Fig. 256 /), Callitris quadrivalvis (Fig. 258), French, and other genera. 

 But the wing-like appendages of the seed of Pinus and Abies are thin plates of tissue 

 which have separated from the seminiferous scale and adhere to the ripe seed. 



The structure of the female flowers of the Coniferae has been the subject of much 

 discussion up to the most recent times. According to one view, which rests chiefly 

 on the history of development, the integument is an ovary, for it appears in many 

 cases in the form of two separate prominences, and this does not agree with the nature 

 of an integument, but seems rather to point to an ovary composed of two carpellary 

 leaves ; each macrosporangium would then be a single female flower. On the other 



1 For the aril of the Taxineae, see above under that division. 



2 Compare the 'pollen-chambers' of the Cycadeae. 



