812 



MACROSCOPIC AND MICROSCOPIC CHARACTERS OF PLANTS. 



In color, the petals of M. vexillaria are a pale pink- 

 magenta, deeper in tint at the base, and with a white 

 margin; those of M. roszlii are white (typically they have 

 a purple blotch at the base) ; those of the hybrid are 

 white with a pink-magenta blotch at the base, identical 

 or very near the shade at the base of the petal of If. 

 vexillaria. 



The labellum is much longer and wider in M. vexil- 

 laria than in M. roszlii and the hybrid. The length in 

 M . roszlii and the hybrid is the same, but the width of the 

 hybrid is slightly more. (Table J43.) All three are 

 cleft at the anterior margin, but the cleft in M . vexillaria 

 is much longer (one-third of length of labellum) and the 

 angle between the lobes much more acute than in 

 M. roszlii, in which the cleft is one-tenth of length of 

 labellum and the angle between the lobes rather obtuse ; 

 while in the hybrid the length of the cleft (one-quarter 

 of length of labellum) and the angle are between those of 

 the parents, though in both respects the hybrid is slightly 

 nearer to M . vexillaria than to M. roszlii. The angles 

 between the lobes at apex are: M. vexillaria 45, M. rcszlii 

 135, M. bleuanaS5". 



At the base of the cleft is an extremely small, pointed 

 apex in M . vexillaria; long acuminate in M. roszlii; and 

 longer and more acuminate in the hybrid than in M. 

 vexillaria, but shorter than in M . rcszlii. 



The color of the labellum at the base is lemon-yellow 

 with three deep-red veins at the middle in M. vexillaria; 

 a deeper yellow with an orange streak on each side, and 

 with purplish-brown lines, in M. roszlii; a brownish red 

 over the veins and spread out to form a fan-shaped area 

 in the hybrid. The rest of the labellum in M. vexillaria 

 is magenta-pink except for a white border in front of the 

 yellow area at the base, and deeper pink over the veins. 

 In M. rcezlii and the hybrid it is pure white. 



The column is much shorter and narrower in M. vexil- 

 laria than in M. roszlii. It is the same length in the 

 hybrid as in M. vexillaria, but in width mid-intermediate 

 between the parents. (Table J 43.) 



COMPABISONS OF THE MICROSCOPIC CHARACTERS OF THE 

 PARENTS AND HYBRID. 



PSEUDOBUUJ. 



Sections of the epidermis of M. vexillaria examined at 

 the middle of the pseudobulb have rectangular or elon- 

 gated hexagonal cells ; very rarely the cells are wider than 

 long. In M. roszlii the cells are less regular in shape; 

 short and wide cells are as frequent as long and nar- 

 row ones. In the hybrid the cells are more often short 

 and wide than long and narrow. If the long and narrow 

 cells of the three plants be compared, it will be found 

 that the length and width of the cells in the hybrid lie 

 between those of the parents, but the length is much 

 nearer that of M. roszlii while the width is slightly nearer 

 that of M. vexillaria. (Table J 44.) 



If the cells of M . vexillaria be compared with the short 

 and broad cells of M. roszlii and the hybrid, it will be 

 found that the length of the hybrid cells lies between 

 those of the parents, but nearer to M. roszlii, while the 

 width is greater in the hybrid than in either parent. 

 (Table J 44.) 



Comparing all the cells, we find that the average 

 length in the hybrid lies between those of the parents, but 

 very much nearer M. roszlii, while the average width in 



the hybrid is greater than that of either parent. (Table 

 J44.) 



The cell walls are rather thick in all three. The 

 outer face of the epidermis is covered with wax. 



Transverse sections of the pseudobulbs were taken at 

 the median point. Outermost, is a layer of oval epider- 

 mal cells with a thick outer wall. These cells are longer 

 and deeper in M. vexillaria than in M. roszlii. In length 

 the hybrid is nearer to M . vexillaria, while in width it is 

 nearer M. roszlii. The outer wall is thicker in M. vexil- 

 laria than in M. roszlii, and in the hybrid, while between 

 the parents, it is much nearer the thickness of M. vexil- 

 laria than that of M. rcszlii. (Table J 44.) 



TABLE J 44. 



Within the epidermis are a few rows of rather small 

 cells (containing chloroplasts) which gradually become 

 larger toward the center of the pseudobulb. These cells 

 have thin walls, store mucilage, and have large inter- 

 cellular spaces. In this tissue the vascular bundles are 

 embedded, the cells around them being smaller and stor- 

 ing a small amount of starch. 



The bundles are very similar in all three, except that 

 the sheath in M. vexillaria is much larger proportion- 

 ally on both sides than in the other parent and the 

 hybrid. The bundles consist outermost of a sheath of 

 sclerenchyma tissue, and then in order inward of a 

 patch of phloem, a few xylem vessels, another small 

 patch of phloem, and then the inner part of the scler- 

 enchyma sheath. They are larger, as a whole, in M. 

 vexillaria than in M. roszlii. In the hybrid in length 

 they are between the parents but much nearer M. rcszlii, 

 but in width exactly mid-intermediate between the 

 parents. The bundles measured were those at the same 

 distance proportionally on the longitudinal axis from 

 the ends. ( Table J 44.) 



LEAF. 



Sections of both upper and lower epidermis from the 

 apex, middle, and base of leaves borne at the top of the 



