774 



A TEXTBOOK OF THEORETICAL BOTANY 



The Female Strobilus. 



The female strobilus is similar to but is larger and blunter than the 

 male, reaching 5 to 7 cm. in length (Fig. 776). The female strobili are not 

 produced in such large numbers as the males. They are borne on very 

 similar inflorescence axes, but the cones are not always sessile. They are 

 bright red in colour. 



In the axil of each bract is one female flower, consisting of a single ovule, 

 terminal on a short axis, and enclosed in two coverings (Fig. 777). The inner 



— ANTHERS 



END OF 



MICROPYLAR 



TUBE 



STAMEN 

 FILAMENT 



NNER BRACT 



OUTER BRACT 



ABORTIVE OVULE 



Fig. 775. — Wehvitschia mirabilis. Longitudinal section of a male flower 



showing the abortive ovule in the centre. 



(From Church, " Phil. Trans. Roy. Soc," B, 250, by permission of the Royal Society.) 



of these is an integument which is extended, as in the other genera, into a 

 long, narrow tube which protrudes several millimetres from between the 

 bracts. It is only free from the nucellus in the upper part (Fig. 778). 



The outer cover, sometimes called the perianth, appears first as a ring at 

 the base of the ovule, but rapidly develops into a two-winged structure which 

 completely covers the inner integument until maturity, when the tube of the 

 inner integument grows rapidly, emerges from a small slot at the top of the 

 outer coat and protrudes beyond the bract of the strobilus (Fig. 779). 



It seems not improbable that this two-winged outer coat really represents 

 two fused perianth segments, and this probability is strengthened by the 

 occasional appearance of two small abortive scales, arranged at right angles 

 to the winged structure and external to it, and perhaps making up, with it, the 

 equivalent of the four perianth segments of the male flower. 



