Glands in the Cotyledons. 443 



with HCl, but notwithstanding the radicles were laden in a 

 similar manner with horizontal raphides. It is evident that 

 the lime could not have been entirely removed from the soil. 

 But a noticeable feature was, that the root developed an 

 abnormal number of root-hairs. I may add here that 

 raphides are absent from root-hairs in Galium Aparine. 



As to other species, the rootlets of Galium glahrum, 

 Thunb. (?), Asperula odorafa, L., and Asperula Iccvigata, L., all 

 showed the same horizontal raphides arranged in columns in 

 the region of the root-cap. Those in Asperula odorata 

 were however somewhat irregular, i.e., all were not horizontal. 

 In other species examined the roots were dormant, and 

 could not be judged of satisfactorily. There is much reason, 

 however, to believe that the same condition will occur in 

 other species. 



Eaphides are very frequent in the testa of SJicrardia 

 arvensis, and may disappear before the embryo germinates, 

 as is the case with Galium Aparine. They are, however, 

 absent in the ungerminated embryo, as in the latter plant. 



It may be stated that the raphides within the root-cap 

 (as elsewhere throughout the plant) of the rootlet of 

 Epilohium montanum, L., are vertical. They are often 

 obscured by a brown pigment in certain cells, which is 

 somewhat soluble in caustic potash. Many seedlings of an 

 Epilobium self-sown in the Onagracea? bed of the University 

 Garden had the raphides in all parts Kkewise vertical. In 

 Lemna minor, L., the raphides were all vertical, and they 

 were numerous within the region of the root-cap.* 



EXPLAXATIOX OF PlATE III. 



Galium Aparine. 



Fig. 1. Embryo (nat. size), from hard seed; its two glands measured 



in height "14, across '13 mm. 

 „ 2. An ungerminated embryo enlarged ; its two nucleated 



glands marked gl. 

 „ 3. A seedling (nat. size), the cotyledonary glands seen in 



fig. 4 ; surface of soil indicated by dotted Hne, m. 



* I have to thank Dr "Wilson for placing material at my disposal, and for 

 general assistance with the work; also Professor Mcintosh, for the use of 

 apparatus. 



