44 



THE OPHIOGLOSSALKS 



I Ik second root arises quite independently ot the stem apex, being developed 

 below the insertion of the primary mot, and its vascular bundle joins that of the 

 Hist root near its base. 



A rudimentary vascular bundle is developed within the cotyledon, and also 

 joins the bundle ot the main root near its base, but no bundle at all is developed 

 within the stem. I he cotyledon reaches only a very small size, but the second leaf 

 soon appears nearly opposite the cotyledon. 



The second leaf also develops at an early period a vascular bundle, which 

 connects with the vascular bundle of the primary root near its point of junction with 

 the second loot, and this exactly resembles the arrangement of the bundles in the 

 bud formed upon the root m 0. moluccanum. It is evident that in the young sporo- 

 phyte of 0. vulgatum, as in 0. moluccanum, the vascular system is made up entirely 

 of the bundles ot the roots and leaves, the stem itself having no proper stele. 



The second leaf finally emerges and appears above ground as the first sterile 

 green leaf of the young sporophyte. Bruchmann states that the second leaf does not 

 appear above ground until five years after it is first formed, and he believes that the 

 sporophyte, at the time its first leaf appears above ground, is nine to ten years of age. 



The third leaf may be fertile, but this is not always the case. 



TIIK ANATOMY OF 1111. YOUNG SPOROPHYTE OF OPHIOGLOSSUM. 



In Ophioglossiun pendulum the young primary root soon breaks through the 

 prothallium and elongates rapidly, but owing to its brittleness it is easily broken 

 off, and it is impossible to state lure just how far it develops before the bud is 

 formed upon it. The development of the second root varies a good deal. The first 

 loot may reach a length of } or 4 centimeters before the second root can be seen 

 at all. The growth of these earlier roots is in all respects similar to that of the later 



ones. 



Th 



ere is a 



■ 



irge tetrahedral apical cell whose divisions are quite regular, 

 and there is soon visible the axial vascular 

 bundle which extends for some distance 

 into the foot, win-re it ends blindly. 1 he 

 vascular bundle of the second root joins 

 the first at the junction of the latter with 

 the foot (rig. 21, /)). 



The first trachea ry tissue appears at 

 the point of junction, and is made up of 

 short, somewhat irregular, pointed tra- 

 cheids with reticulate thickenings. From 

 this point the development of the tracheary 

 tissue proceeds toward the apex of the roots. 

 The bundle is diarch, as is plainly seen in 

 cross-sections ( fig. 27. J: ). I he endodermis 

 is very clearly defined and tin characteristic 

 radial markings an- extraordinarily char, 

 especially in sections treated with a double 

 stam of satranme and gentian violet. I he 



tracheary tissue is also beautifully differen- 

 tiated by this stain. I he bundle is slightly 

 elliptical in form and tin- protoxylem ele- 

 ments appe.11 at the foci of" the elliptical 

 section. I he first appearance of the tracheary tissue is some distance back of the 

 apex and the development proceeds rather slowly. In the oldest part of the roots 



A. Longitudinal .section of an <>U!er bud of Oftliioglossum 

 moluccanum. X50. j», stem apex; /' first leaf oi 

 bud; '' . h r v t root <>f tin* bud. 



It. Stem apex ..1 same. X90. 



