Ramaley : SEED AND SEEDLING OF WESTERN LARKSPUR. 419 



bock,* mentions that in Delphinium troll if olium and in Del- 

 phinium consolida the petioles of the cotyledons are united in 

 the same way. 



Anatomy of the Seedling. As this has apparently not been 

 described for any species of Delphinium a somewhat extended 

 account will be given. It may be well to state at the outset 

 that the present writer has studied only the seedling and not the 

 flowering stem. The young root has a thick cortex and small 

 central stele. The endodermis, though thin-walled, is con- 

 spicuous in properly stained sections because of the thickened 

 cuticularized spots on the radial walls. The xylem is arranged 

 in two small groups. (See Fig. 7.) In an older portion of 

 the root (Fig. 8) the xylem forms an elongated mass in the 

 center of the stele. Higher up the vascular tissue extending to 

 the cotyledons passes out abruptly on either side at right angles 

 to the longer diameter of the xylem mass. (Fig. 9.) Passing 

 upward the xylem strand divides into six or more bundles as 

 the transition occurs from root to stem. At the same time 

 the cortex becomes thinner. In a cross section at this point 

 (Fig. 10) the cotyledonary sheath is seen surrounding the stem. 

 In a section somewhat higher up (Fig. n) the bases of the early 

 foliage-leaves may be seen placed alternately. Here the stem 

 abruptly narrows and a rupture of the cotyledonary sheath per- 

 mits the emergence of the first foliage-leaf. (Figs. 2 and 3). 

 The cotyledonary sheath now becomes smaller, narrowing to 

 form the structure previously spoken of as resembling a hypo- 

 cotyl. Sections of this structure show that its component 

 petioles are not completely fused at any point (Fig. 12.) A 

 slit-like passage, lined with epidermis, extends upward to the 

 point where the petioles separate completely. 



Anatomy of the cotyledonary Sheath. No difference is to 

 be noted between the outer epidermis and that lining the cavity. 

 It is, in both cases, composed of elongated cells which are 

 square in cross section. There are two vascular bundles, one 

 for each component petiole. These are small but show no pe- 

 culiarities in structure. The fundamental tissue is a large- 

 celled parenchyma. 



Anatomy of the Lamina of the Cotyledons.- Each lamina 

 has three principal veins which send off numerous branches. 

 The epidermis is composed of thin-walled cells, somewhat 



*Lubbock. On Seedlings, 2: 96. 1892. 



