GYNGECIUM OF GYMNOSPERMS. 



273 



511. In the Araucaria tribe the ovuliferous or carpel-scale is 

 throughout smaller than the bract, and is completely adnate to 

 it, or with only the tip free ; that of Araucaria (Fig. 565) bears 

 only one ovule, high on the carpel, the orifice downward as in 

 the Pine tribe. In Taxodium, Sequoia, and the like, the cone- 

 scale is equally inferred to be composed of bract and carpel-scale 

 united ; and indications of this composition are to be observed. 

 The ovules (from two to several) are at the base of the scale, 

 erect and free. The cone-scales are alternate and spiral on the 

 axis, but indistinctly so in Taxodium, the Bald C} r press or 

 so-called Cypress of the Southern United States. 



512. In the true Cypress tribe (Cupressinese) the cone-scales, 

 which are never numerous, are opposite or verticillate, i. e. like 

 the foliage- leaves, in whorls of twos, threes, or 

 sometimes fours ; and the ovules are from two to 



568 



1878, where it is fully adopted. It was suggested by certain rather common 

 monstrosities, and by the two combined leaves of Sciadopitys. 



According to this view, the ovuliferous scale in the Pine tribe is com- 

 posed of two leaves of an arrested and transformed branch from the axil of 

 the bract, which are in the normal manner transverse to the subtending 

 bract, are here carpellary, each bearing an ovule on the dorsal face ; the two 

 are coalescent into one by the union of their posterior edges, and the scale 

 thus formed is thus developed with dorsal face presented to the axis of the 

 cone, the ventral to the bract. It is therefore a compound open carpel, 

 composed of two carpophylls. This character of being fructiferous on the 

 back or lower side of the leaf occurs in no other phsenogamous plants, but is 

 the rule in Ferns, from something like which Conifers may be supposed to 

 have been derived ; the ovules of the one in this regard corresponding to the 

 sporangia of the other. 



FIG. 565. Vertical section (in diagram) of a bract, adnate" carpel-scale, and adnate 

 ovule of Araueari.a imbricata. After Eichler. 



FIG. 566. Bninuhlet of the American Arbor- Vitse, considerably larger than in na- 

 ture, with a forming fertile cone 567. One of the scales removed and more enlarged, 

 the inside exposed to view, showing a pair of naked erect ovules on its base. 



FIG. 568. Fertile flowers of true Cypress (Cupressus sempervirens), after Baillon: a 

 forming cone, with one scale cut away, to show the cluster of ovules under it. 



18 



