THE ROOT. 77 



leaves of the celery (Apium graueotens)^ Hibiscus, and 

 Streptocarpiis which had been cut, but not severed 

 from the stem. Very many plants, more especially 

 Begonia, Gloxinia (to mention merely two well-known 

 cases), have the power of emitting roots from their 

 leaves after these have been taken off, incised in 

 various ways, and laid in a damp situation. 



Fig. 21. — Bryophyllum calycinum. Adventitious roots each growing" 

 from a leaf-notch. (After Groebel.) 



(4) On Floral Parts. 



Dr. Renclle showed the writer an ovuliferous scale 

 of a cone of the spruce (Picea excelsa) which had been 

 lying in a very damp place ; from its surface quite a 

 long root had grown out. 



(5) On a Prothallus. 



Lang induced in prothalli of the hart's-tongue fern 

 (Scolopendrium vulgar e), which had been grown under 

 artificial conditions, the production of roots such as 

 are normally developed by the sporophyte ; this must 

 be regarded as a stage in the formation of an adven- 

 titious bud. 



