318 



PHILOSOPHICAL NOTES ON 



Fig. 136. Saccate glume of Briza minora Syme's " Brit. Bot.," p. 132. 



On the 10th February 1891, however, Dr. Masters gave 

 me some abnormal leaves of Yucca flaccida. All of them had 

 two abnormal lobes on their margins, as shown in Fig. 137. 



Fig. 137. Abnormal leaves of Yucca flaccida : (a) with lobes on margins, 



(6) with spurs. 



(a) In some the lobe had turned into a hollow horn or spur 

 as in (6) . There was no indication of either the lobes or the 

 spurs having been caused by insects. The ones and the others 

 were, so to speak, spontaneous productions, probably repeating 

 the teeth of other plants, such as the Agave. 



In May 1891, among the interesting collection of plants 

 owned by Wm. Hanbury at " La Mortola," on the Riviera, I saw 

 a Sempervivum, with rather thin leaves, having a tendency to 

 similar lobular projections on the margins of its leaves. 



