Vol. 27 



BULLETIN 



Q 



No. 7 



OF THE 



TORREY BOTANICAL CLUB 



JULY 1900 



On the Development of Saururus cernuus L. 



By Duncan S, Johnson 

 (With Plate 23) 



The naked flower and the form of the carpel of Saururus have 

 always led botanists to place it among the simpler Dicotyledoneae, 

 usually in the Piperaceae. Engler has recently aroused new in- 

 terest in all of these forms by separating from the Piperaceae the 

 genera Saururus, Auemiopsis, and Houttuynia and constituting of 

 them the family Saururaceae, which he regards as the simplest of 



■ 



the Dicotyledoneae after Casuarina. It was the desire to discover 

 whether the evidence obtained from a study of the details of de- 

 velopment would bear out this view of Engler that led me to under- 

 take work on the Piperaceae collected by Professor Humphrey in 

 Jamaica in 1897, and on material of Saururus cernuus, collected in 

 Baltimore and North Carolina in 1 899. The work on the Piper- 

 aceae will appear elsewhere and I give here a preliminary account 

 of some features of the development of Saururus. 



The one to three spikes of flowers are terminal in origin, but 

 are soon pushed aside by the more vigorous growth of the last 

 lateral bud. The flower consists of six stamens, and usually four 

 I carpels somewhat fused at the base, borne on the upper surface of 

 a spoon-shaped bract. According to De Candolle the whole 

 flower may sometimes be stalked from the axil of the bract. 



The stamens arise on the upper and outer surface of the bract 

 when the latter is but a slight swelling from the side of the axis. 

 Soon after this the carpels appear as horseshoe-shaped elevations 

 in the area within the circle of stamens, the lower flowers of the 

 spike being always much further developed than the upper ones. 



365 



