86 THE PHENOMENON OF 



than the preceding scattered hypsophyllary leaves; the 

 8 inner invohicral leaves, in the axils of which are seated 

 the 8 florets of the ray, are 5—6 times as long and broad 

 as the outer, lighter coloured, and more scarious. This 

 constitutes the maximiun of the hypsophyllary formation; 

 the succeeding bracts (palese) are shorter, almost filiform, 

 and transparent, with a thin brown central streak. Another 

 example, which exhibits not only a sinking and reascent, 

 but an actual disappearance, at the transition from the 

 euphyllary to the hypsophyllary formation, is afforded by 

 Emilia sagittata [Cacalia sonchifolia of gardens.) The 

 large euphyllary leaves embracing the stem with their 

 arrow- or heart-shaped bases, are follovv'ed by a narrow 

 linear transitional leaf, from the axil of which arises the 

 first branch of the corymbose inflorescence. From 2 to 4 

 leaves are thus wholly suppressed, their existence being 

 merely detected by the branches of inflorescence being 

 apparently devoid of subtending leaves. The leaf- 

 formation rises up again in the involucre of the ter- 

 minal capitule, composed of 13 equally long, linear 

 hypsophyllary leaves, and generally vanishes again on 

 the ''receptaculum nudum." A similar disappearance 

 and re-advance of the hypsophyllary formation, only 

 distributed on distinct axes, is seen in those Umbelliferae 

 which are devoid of an involucre, but have an involucel, 

 as for instance in Angelica sylvestris, Seseli montanum 

 and Hippomarathrum, and liupleurum rotundi folium. 

 The leaves of the involucels are at the same time the 

 bracts (subtending leaves) of the outermost flowers of the 

 umbellule, while the subsequent, more internally situated 

 flowers, arise from the axils of suppressed leaves. Thus, 

 the Bupleurum mentioned has only five involucellar 

 leaves, but eight to thirteen flowers in each umbellule, 

 the central flower not included; therefore three to eight 

 flowers must spring from the axils of invisible leaves. A 

 third large order, in which the hypsophyllary formation 

 occurs in similar conditions, is that of the Grasses. Here 

 it is universal for the euphyllary formation to be followed 



