52 THE PLANT WORLD. 



in which the simple original leaf was modified in the varying courses 

 of its evolution into modern forms. It maybe observed that the veins 

 of the lower bud scales of a plant are approximately parallel and we 

 conclude that the earliest forms evolved from the primitive leaf in- 

 cluded all its parts in the blade and were parallel-veined as we see 

 them in the simply organized monocotyledonous plants of the present 

 day. In some cases, however, the lateral stipular parts are distin- 

 guishable at their apices as in the formation of the ligule of grasses, 

 the stipule of pond-weeds, which' is a ligule rendered axillary by the 

 degeneration of the petiole, and the lateral parts of sheathing petioles 

 as in the calla and palm. Similar cases occur among the dicotyledon- 

 ous plants in the ochrea of the knot-weeds and the sheathing petiole 

 of many members of the crowfoot and parsley families. 



In some of the lower families of dicotyledonous plants the whole 

 of the primitive leaf has been transformed into the modern form. In 

 Sassafras this transformation may be distinctly traced in a series of 

 bud-scales and early leaves. In families with stipulate leaves, the 

 modifications have been as we have seen them in false indigo, the ev- 

 olutionary changes ceasing at various points giving origin to stipules 

 with varying degrees of adnation or to those that are entirely free. 

 As also it was observed that the stipules finally disappeared altogether, 

 so some families with leaves once stipulate may have lost nearly all 

 trace of them. Such is the honeysuckle family with leaves now usu- 

 ally exstipulate, but fugacious stipules are present in some species of 

 Viburnum and elder, and one European species of elder has perma- 

 nent stipules. 



Stipules are then the representatives of the lateral portions of 

 the primitive leaf when separated in a greater or less degree from 

 the rest of the leaf, but the same primitive tissues form the ligule, 

 ochrea and the margin of sheathing petioles and are often incorporated 

 with the other parts of the primitive leaf as the wings of petioles and 

 as lateral-basal portions of leaf -blades. 



One of the most omnivorous parasites of the vegetable kingdom 

 is our common dodder ( Ciisciita Gronovii)* Its favorite host plant is 

 the goldenrod, upon several species of which it is nearly always to be 

 found ; but I have found it also on the red maple, blackberry, pepper- 

 bush {Clethra), and some asters. That it should attack a plant with 

 such thick bark as the maple is both interesting and remarkable. It 

 would be interesting to know upon how many other species of herbs 

 and shrubs this plant has been found parasitic. — Willard N. Clute, 

 New York City. 



