Occurrence of Foliage-leaves in Ruscus androgynus. 139 



supposed to have become united to each other by their 

 posterior margius : iu either case the superior position of 

 the phloem elements would thus be accounted for. The 

 latter of these alternatives was adopted in 1872 by Von 

 Mohl.* 



In 1868, Sachs f advanced the opinion that the female 

 cone represents a single female flower with a spike-like 

 arrangement of open carpels (the bracts of authors), each 

 with a placental excrescence or appendage from the inner 

 surface of its base, this placenta being flatly expanded to 

 form the squama fructifera of authors. Sachs's view has 

 been adopted and elaborated by Eichler,J who relegates the 

 placental appendage to the category of ligular formations, 

 to which belong the scales on the inner face of the petals 

 in Lychnis and Silene, the corona of Narcissus, the stamens 

 on the inner face of the petals in Primulacecc, &c., in all 

 of which there appears to be the same remarkable arrange- 

 ment of the fibro-vascular elements, with the phloem directed 

 superiorly or internally, and the xylem inferiorly or exter- 

 nally.§ Such a hypothesis would, no doubt, account for 

 the arrangement of the fibro-vascular elements in the 

 squama ; and it has the further recommendation of correlat- 

 ing, as homologically equivalent, the female cone with the 

 so-called " male cone," which is undoubtedly a single flower. 

 It is to be borne in mind, however, that it is a hypo- 

 thesis based upon another hypothesis, viz., that the female 

 reproductive structures are naked ovules, — one which I 

 still hold to be destitute of any solid foundation ; and, 

 furthermore, it appears to me that the idea of the squama 

 being merely a ligular appendage to the bract is wholly at 

 variance with what may be seen in cones exhibiting 

 " retrograde metamorphosis " into the ordinary branch 

 form, where the not unfrequent formation of an axillary 

 bud is very manifestly part of the metamorphosis of the 

 squama. 



B. As to the " needles " of Sciadopitys. The " needles " 



* Bot. Zeitung, 1872, p. 23. 



t Sachs, Lehrhuch dcr Botanik, 1868, p. 427. 



+ Eicliler, " Uber die Weiblicheu BUitheu der Comiftvcxi," Ahhandl. der k. 

 Akad. d. Wissensch. zu Berlin, 24 Nov. 1881. 



§ See Van Tieghem, "Structure du Pistil des Priinulacees et des Theo- 

 phrastees," Ann. des Sc. Nat., 5° Ser. xii. (1869) p. 329. 



