MISCELLANEOUS: EXPERIMENTAL TERATOSIS 587 



4405, 449, 450). Apparently, on the internodes the shoots are 

 not restricted to the vicinity of the glands, but this may be more 

 apparent than real, since the glands disappear early. The very 

 young normal tissues of this begonia are red, the wound-repair 

 tissue also is red. The epidermis of developed organs is green 

 but those parts of the leaf giving rise to the acicular hairs are 

 red, as if still embryonic. 



13. I was led to study this curious plant, which is smooth 

 rather than conspicuously hairy or scaly (Fig. 425), thinking it 

 might throw some light on the origin of teratomas in animals 

 and hoping that I might be able to discover some law underlying 

 its peculiar and apparently lawless behavior. I had one plant 

 at first, from which by cuttings I have propagated many. For 

 a long time this plant, which was left undisturbed, behaved much 

 like any other begonia plant. It refused to throw new adven- 

 tive shoots, although it bore some old ones, and I was much dis- 

 couraged, but by persistently experimenting with it I have 

 succeeded in making it do wonders. The history of my plant, as 

 far as I have been able to trace it, is that it was propagated from a 

 plant descended from one which was received at the Washington 

 Botanic Garden more than 18 years ago. The present super- 

 intendent does not know its origin but as Mr. Smith, the former 

 superintendent, was a Kew man, I suspect it to have come from 

 the Kew Gardens where B. phyllomaniaca has been grown for a 

 long time. 



14. In good soil, exposed to medium hothouse temperatures 

 and not over- watered, l the plant grows freely and is healthy. 

 There is, however, little substance to it. By this I mean that 

 it has a large watery pith, a thick soft cortex and only a thin 

 woody cylinder, the amount of water in it being excessive as 

 compared with most plants of its size and age. For example, 



1 If watered abundantly the plant in our houses is frequently attacked by a 

 fungus (Fusarium sp.) and rots off at the surface of the earth. 



Z, a well developed proliferous leaf; b, c, d, branches of recent origin. The corky 

 proliferous internodes are between 1' and Z. Their back was free from cork and 

 entirely proliferous (Fig. 434, Sub. 2). Z was the small top leaf of July 25, cor- 

 responding to leaf A in this photograph. For upper face of Z 1 see Fig. 433. 

 Photographed October 11, 1918. About Y nat. size. 



