796 



MACROSCOPIC AND MICROSCOPIC CHARACTERS OF PLANTS. 



FLO WEB-STALK. 



Transverse sections of the flower-stalk of the parents 

 and hybrid were made at a point near the apex. Exter- 

 nally is a layer of rather thick-walled cells constituting 

 the epidermis, with a thick cuticle on the outer face. 

 These cells are oval, and wider than deep in L. purpurata, 

 but somewhat spherical in C. mossice and the hybrid. 

 They are much larger in L. purpurata than in C. mossice, 

 and are a little deeper and narrower in the hybrid than 

 in either parent. (Table J 19.) 



Beneath the epidermis is a layer of thick-walled, oval 

 cells, the hypodermis. These cells in L. purpurata are 

 not regular in size, but vary from rather small cells (22 

 by 32/t) to cells over twice their size (54 by 68/x). In C. 

 mossice the layer is composed of small, oval cells that are 

 quite uniform in size. In the hybrid the layer resembles 

 that in C. mossice, but the cells are a little deeper. 

 (Table J 19.) 



The cells of the first layer beneath the hypodermal 

 layer in L. purpurata become larger, and in the second 

 layer they are still larger and have attained their maxi- 

 mum size. In C. mossice they become larger very grad- 

 ually, not reaching their maximum size until in the 

 fourth or fifth layer. In the hybrid they reach their 

 maximum size in about the third or fourth layer. These 

 cells are rather thin-walled, contain chloroplasts, and 

 form' a cortical cylinder which is wider in L. purpurata 

 than in C. mossice and smaller in the hybrid than in 

 either parent. (Table J 19.) 



There is not a distinct layer of cells forming an 

 endodermis, but the bundles are embedded in fundamen- 

 tal tissue in the form of a rather distinct central cylinder. 

 The bundles are larger in L. purpurata than in C. mossice, 

 and smaller in the hybrid than in either parent. (Table 

 J19.) 



There is a larger proportion of phloem in the bundles 

 of L. purpurata than in C. mossice, and in the hybrid 

 the amount is proportionately exactly mid-intermediate 

 between those of the parents. (Table J 19.) 



FLOWER. 



Sections of the upper epidermis of the sepal were 

 taken at the median point. The cells are flat in L. pur- 

 purata; papillose in C. mossice and less papillose in the 

 hybrid than in C. mossice. The color present in C. mossice 

 and the hybrid is due to a faint pinkish-lavender coll sap 

 in the mesophyll layer, which is darker in C. mossice than 

 in the hybrid. No colored sap is present in L. purpurata. 

 The cells are longer and narrower in L. purpurata than 

 in C. mossice. They are longer in the hybrid than in 

 either parent, and though the width is between those of 

 the parents it is much nearer that of C. mossice. (Table 

 J19.) 



Stomata are present on the upper epidermis. They 

 are much more numerous in L. purpurata than in C. 

 mossice, but less numerous in the hybrid than in either 

 parent. In L. purpurata 1 in 2 fields; in C. mossice 

 1 in 7 fields; in L.-C. canhamiana 1 in 11 fields. 



The section of the lower epidermis of the sepal at the 

 median point shows the lower epidermal cells to be flat, 

 not papillose. The cells are larger in L. purpurata than 

 in C. mossice, and though in the hybrid between the 

 parents in size, the length is nearer that of C. mossice, 

 but the width nearer that of L. purpurata. (Table J 19.) 



Stomata in the lower epidermis are more numerous 

 in L. purpurata than in C. mossice, and more numerous 

 in the hybrid than in either parent. In L. purpurata 



1 in 5.5 fields; in C. mossice I in 7.5 fields; in L.-C. can- 

 hamiana 1 in 3.6 fields. 



Hairs are present on the lower epidermis at the mid- 

 dle of the sepal. They each consist of an awl-shaped basal 

 cell with a thin-walled, thimble-like end cell. They are 

 numerous and long in L. purpurata; rare and much 

 shorter in C. mossice; and in the hybrid slightly less 

 numerous than in L. purpurata, and shorter than in 

 either parent. In L. purpurata 1 in 5 fields, 97.2/x long; 

 in C. mossice 1 in 22 fields, 75.6/t long; in L.-C. can- 

 hamiana 1 in 6.3 fields, 68.4/t long. 



Sections of the upper epidermis of the petal were 

 made at a median point. The color, which is identical 

 with that of the sepals and due to the pinkish-lavender 

 cell sap in the mesophyll, is deeper in C. mossice than in 

 the hybrid. No colored sap is present in L. purpurata. 

 The cells are very slightly papillose in L. purpurata and 

 smaller than in C. mossice; they are distinctly papillose in 

 C. mossice; and in the hybrid they are not quite as papil- 

 lose, and very nearly as large as in C. mossice. (Table 

 J19.) 



Stomata are present on the upper epidermis. They 

 are much more numerous in L. purpurata than in C. mos- 

 sice, in which latter they are very rare. In the hybrid 

 the number is between those of the parents, but slightly 

 nearer L. purpurata. In L. purpurata 1 in 1.5 fields; 

 in C. mossice 1 in 25 fields; in L.-C. canhamiana 1 in 6 

 fields. 



Careful examination of the upper epidermis of the 

 petal at the middle failed to reveal any hairs in C. mossice 

 and the hybrid. Hairs are very rare in L. purpurata, only 



2 having been found in 80 fields. They were similar 

 to those on the lower epidermis of the sepal, and had an 

 average length of 90/t. 



Sections of the lower epidermis were made at the 

 middle of the petal. The cells of the lower epidermis are 

 flat in L. purpurata; papillose in C. mossice; and only 

 very slightly papillose in the hybrid. They are shorter 

 and broader in L. purpurata than in C. mossice, and 

 larger in the hybrid than in either parent. (Table J 19.) 



Stomata in the lower epidermis are more numerous 

 in L. purpurata than in C. mossice, and more numerous 

 in the hybrid than in either parent. In L. purpurata 

 1 in 5 fields; in C. mossice 1 in 9 fields; in L.-C. canha- 

 miana 1 in 4.3 fields. 



Sections of the upper epidermis of the middle lobe 

 of the labellum were taken at about the median point. 

 This area is crimson-purple in L. purpurata, due to a 

 crimson-purple cell sap which fills the papillose epider- 

 mal cells; blotched magenta (more red than in L. pur- 

 purata) in C. mossice, due to a red-violet cell sap; 

 blotched magenta in the hybrid, due to a red-violet cell 

 sap. The cells are papillose in all three, but the papillse 

 are much more elongated and narrower in C. mossice 

 than in L. purpurata and the hybrid. The papillae of 

 the hybrid are in length nearer those of L. purpurata 

 than those of C. mossice. (Table J 19.) 



The basal part of the cell is smaller in L. purpurata 

 than in C. mossice and larger in the hybrid than in either 

 parent. (Table J 19.) 



