412 BULBILS ()i\ THE SLT-TLKRANEAN ORCIANS OF PLANTS. 



South Africa. It is further seen that in most cases, 2'i::.. 9 out 

 of 12 species, the absence of fruit or seeds has been actually 

 observed, while in the other three cases this was probable. The 

 question naturally arises, is the formation of the bulbils the 

 cause of the barrenness, or is the barrenness the cause of the 

 appearance of the bulbils? In most cases experimental investi- 

 gation could probably decide the question ; but two of the above 

 cases give some indication of the primary cause, vis., that of 

 Mlcranthus plaiitagiiiats X fistulosus and Gladiolus cuspidafus. 



The Micranthus is a hybrid, and as it is known that hybrids 

 are usually sterile, the formation of bulbils in the axils of the 

 bracts of the spike is apparently caused by the barrenness, the 

 materials required in fertile plants for the formation of the 

 seeds being utilised for the production of the bulbils of the 

 seedless hybrid. 



The evidence afforded by Gladiolus cuspidatns is even 

 stronger, for the barrenness of these plants is ol)viouslv caused 

 by the rust, and the formation of the bulbils must be con- 

 sidered as a secondary process, which enal)les this species to 

 propagate itself ev^en in localities where the fungus attacks it 

 regularly. In other localities, and also in gardens, G. cuspidatns 

 often remains quite healthy, and produces perfect flowers, but I 

 ha\'e not been able to ascertain whether these plants are fertile 

 and whether they bear bulbils or not. 



1 havo no doubt that more such cases will be found in our 

 flora if more attention be paid to the subject ; hence collectc:)rs 

 of i)lants could much assist in the matter if they would record 

 their observations when gathering and drving sucli specimens. 



Llst of SoTTti African Speciks Mi;ntio\i:i). 



Albuca minor L. 



A. z'ii'idi flora Jac(|. 



A)itholyca rcvolnta Burm. 



Aspleninin (jenunifcrn)n Schr. 



Gladiolus cuspidatns jact). 



(7. grandis I'himb. 



Hcspcrautha hut hi f era Baker 



Homcria ininiala Sweet. 



Marchantia polyiiiorpha L. 



MclaspJiccrula (jraniinca ( L. fil.) Ker 



Micranthus fistulosus (Jac(|.) Eckl. 



M. plantar/incus { Ker ) I"aM<1. 



.1/. plantac/incus, \ar. jnnccus. liaker 



M. plantayincus >< fistulosus .Marl. 



Mor(ca bitnniinosa ( L. hi.) 



M. ramosa ( Thunl). ) Ker 



M. 7'iscaria ( L. til.) Ker 



Ornithogalum thyrscidcs |ac(|. 



O.valis cernna I.. 



iVatsonia iridifolia ( |ac(|.) Ker 



Uro)ii\'CCs Cihuiioli \\ Ilenniiur-^ 



