270 



THE FLOWER. 



genus Gnetum, shrubs or trees, with nearly the aspect of 

 Angiospenns, having broad and pin nately- veined leaves ; Wel- 

 witschia of tropical W. Africa, remarkable for its persistent 

 cotyledons which form the only foliage of a woody and long- 

 enduring plant, and for its stem or trunk which broadens with- 

 out lengthening, except in its flower-stalks ; also Ephedra, of 

 much branched shrubs, mainly of warm-temperate regions, leafless 

 or nearly so, one species of which inhabits Europe and two the 

 southern borders of the United States. 



506. The flowers in all Gymnosperms are diclinous, either 

 dioecious or monoecious ; except that those of the strange Gneta- 

 ceous genus Welwitschia are structurally polygamous, the male 

 flowers having a well-formed but sterile gynoecium. 



507. In Coniferae, the largest and most important type, are 

 embraced all the familiar Gymnosperms of temperate regions, 



Pines, Firs, Cedars, Cypresses, which 

 bear their flowers in catkin-like clusters 

 and their fruit in cones, and also the 

 Yews and allied trees which do not 

 produce cones. Perianth being want- 

 ing and the sexes wholly separate, the floral type 

 is so degraded that it becomes doubtful whether 

 each cluster of anthers, or of ovuliferous scales 

 or ovules, constitutes a blossom or an inflores- 

 cence. Certain botanists look upon a whole 

 catkin, and others upon a male catkin only, of 

 a Pine or Fir as forming one flower. It is here 

 assumed that each stamen 

 of the one and each ovu- 

 liferous scale of the other 

 answers to a flower of the 

 simplest sort. 1 The anthers 

 555 are extrorse, the cells or 



pollen-sacs belonging to the outer or lower side of a scale or a 



1 It will be seen that, for the female flowers, this follows of course from 

 generally accepted view ; and, where this is conceded, analogy may extend it 

 to the male catkins also: yet in such cases, where all the phylla of an indefinite 

 simple axis are stamens, spirally arranged on it, the difference between 

 inflorescence and male flower completely vanishes. 



FIG. 554. Female flower of a Yew, an ovule surrounded by its bracts. 555. Longi- 

 tudinal and more enlarged section of a female flower of Yew and of the tipper part of 

 the shoot it terminates : the thick coat of the ovule open at the top, the nucleus within, 

 and the beginning of the disk outside of the coat, are seen in section. After Stras- 

 burger. 



FIG. 556. Young fruit (berry-like cup surrounding the seed) of Yew. 557. Longi- 

 tudinal section of a mature fruit of the same. After Decaisne. 



