878 



Often, however, they are of a concentration which makes possible the 

 formation of flower buds. 



In general practice at times the petiole is used for jiropagation instead 

 of the leaf, in case the leaf itself is too tender. A recent example is the 

 propagation of the cultivated forms of Begonia scmperflorens, which is sold 

 under the name of Gloire de Lorraine and greatly prized as a winter 

 bloomer'. In February the most vigorous leaves are cut ofif close to the 

 stem and the petiole set i to 2 cm. deep in sand and peat mold. At a tem- 

 perature of 18 to 22 degrees C. these petioles form root balls as large as 

 walnuts. Other begonias as, for example, the Rex forms set roots from 

 their petioles but almost never develop strong buds. The petioles of cab- 

 bage, celery and other fleshy plants behave similarly. 



The flower stems of Primula sinensis may be used successfully as cut- 

 tings. Cramer'- used flowers with the leaf-like perianth of this plant, in 

 which buds were produced in the axes of the reproductive leaves. A case, 

 which Baillon observed, showed that the fruit could also be used as cuttings ; 

 in this, roots developed from the fruit of a cactus^. The same author also 

 cut in two just above the base the ovary of Jussieus salicifolia. This bore 

 two leaflets near the centre, and was cut during and after blossoming in 

 such a way that the ovules could be seen ; these cuttings were set in a pot. 

 Three weeks later the well-rooted cuttings w^ere transplanted. A small 

 branch with scales appeared in the angle of the carpels. The upper part of 

 the blossom died and a circular scar was formed*. Irmisch describes root 

 formation on the cotyledons of Biinium crcticum and Carnm Bulhocasta- 

 niinv'. I have seen root formation in the broken-ofif cotyledons of beans 

 (Phaseolus vulgaris). Carriere found roots on the fruits of Lilium lanci- 

 foliiini. Reinling" found flower stems of Echevcria which, in moist sand, 

 had grown roots. 



Hildebrand" describes a fruit of Opuntia Ficus indica out of w^hich a 

 second had sprouted ; both fruits after separation from the iplant developed 

 leaf sprouts. The same thing happened with blossom buds of Opuntia 

 Raffinesquiana. Therefore, each plant organ may be capable of developing 

 leaf sprouts b} the formation of adventitious buds, provided first that it 

 contains enough resen-e substances to live for some time separated from the 

 parent plant, and secondly that the external conditions are favorable. A 

 summary by Magnus"* gives further details together with the theories of 

 Klcbs, Goebel and others. 



1 Kir.st, Vermeil runs' fler Begonie "C51()ire dc Lorraine." I'rakt. Katgeber im 

 OJ:)st- u. Gartenbau 1906, No. 5. 



- Bildungsabweichungen, p. 37. 



3 Vegetable Teratologie, p. 160. 



* Bot. Zeit. 1S6.5. p. 527, from Adansonia, Vol. I, p. 181. 



s Flora 1S5S, p. 32, 42. 



6 Beinling, Unler.suchungen iiber die Entstehung der adventiven Wurzeln und 

 Laubknospen an Blattstecklingen von Peperomia.' Inaug.-Diss. Breslau 1878. 



7 Hildebrand, F., tjber Bildung A'on Laubspro.ssen aus BlUtensprossen von 

 Opuntia. Ber. d. Deutsch. Bot. Ges. 1888, Vol. VI, p. 109. 



*< Magnus, Weiner, Regenerationserscheinungen bei Pflanzen. Naturwissensch. 

 AVochenschrift 1906, No. 40. 



