1899] Johnson. — The Irish ' Characecz. 153 



Leaflets far weaker developed on the hack of the leaf 

 and appearing only as papillae. 

 ** Leaflets on the back of the leaf almost wholly un- 

 developed, scarcely longer than broad. 



38. C. fcetida, A. Br., or C. vulgaris, Linn. 

 * The nodal cells of the cortical tubes develope more or 

 less long spines which are in part solitary, in part 

 tufted, but sometimes tufted only. Leaflets de- 

 veloped on the underside of the leaf are half as long 

 as those on the upper side. 

 ** Leaflets on the back of leaf half as long as or shorter 

 than those on the dilated (inner) part, mostty 

 incrusted. 

 *** Secondary and primary tubes almost equally well 

 developed, leaflets on the dilated part longer than 

 the fruit (oospore). 41. C. hispida, Linn. 



3. The number of the series of cortical tubes is three times 

 that of the leaves of the corresponding node : 



Triplostichce. A. Br. 

 t Dioecious. 



a. Spines present, mostly distinctly evident. 



In addition to shorter leaflets on the inner side five 

 longer ones on the side and on the dilated side. 

 a. Covering leaflets and subsidiary leaflets as long as the 

 two lateral ones, developing unicellular bulbils in 

 mucilage. 



43. C. aspera, Willd. 



b. Spines absent, only two subsidiary and one covering 



leaflet, rarely two short lateral leaflets developed. 

 a. Cell-wall of cortical tubes very thin, stem and leaves 

 becoming when dry as thin as paper, producing 

 strawberry-like bulbils in mucilage. 



[45. C. fragifera, Durien.l 

 |8. Stem and leaves, but especially the cortical tubes 

 thick walled, remaining in drying almost round, 

 stiff, shining, without bulbils. 



44. C. con/livens, Braun. 

 \ Monoecious. 

 Leaflets on the back of the leaf undeveloped or wart- 

 like only, oospore black. 

 a. Without spines or warts, primary and secondary rows 

 of cortical tubes equally well developed. 



48. C. fragilis, Desv. 

 /3. The primary or middle rows project above the 

 secondary or intervening rows and bear distinct 

 warts or spines. 49. C. delicaiula, Braun. 



A3 



