MACROSCOPIC AND MICROSCOPIC CHARACTERS OF PLANTS. 



821 



not as thick in C. spicerianum as in C. villosum, and 

 less thick in both hybrids than in either parent. The 

 cells are less deep but wider in C. spicerianum than in 



TABLE J 53. 



C. villosum. In both hybrids they are deeper than in 

 either parent, and in C. lathamianum inversum they are 

 wider than in either parent. In C. lathamianum, how- 

 ever, they are between those of the parents in width, but 

 slightly nearer C. villosum. (Table J 53.) 



Between the elongated upper epidermal cells and the 

 lower epidermal cells are many layers of small, rounded, 

 chlorophyll-containing cells, embedded in which is the 

 midrib bundle that consists of a patch of thin-walled 

 cells, the phloem below, and thick-walled cells, the xylem 

 above, and all surrounded by a fibrous sheath. The mid- 

 rib bundle is much smaller in C. spicerianum than in 

 C. villosum. In both hybrids the depth of the bundle 

 is between those of the parents, that of C. lathamianum 

 inversum being almost exactly mid-intermediate between 

 those of the parents; and that of C. lathamianum being 

 very near C. villosum. The width in C. lathamanium 

 inversum is between those of the parents, though nearer 

 C. villosum; and that of C. lathamianum is greater than 

 in either parent. 



The thickness of the transverse sections at the mid- 

 rib of the four plants was also measured. C. spicerianum 

 was found to be not as tKick as C. villosum, but the two 

 hybrids have a greater thickness than in either parent. 



FLO WEB-STALK. 



Sections of the epidermis of the flower-stalk were 

 examined just below the ovary and also at a point midway 

 between the ovary and base of the flower-stalk. At the 

 former position the epidermal cells are somewhat rectan- 

 gular, with thin lateral walls and a thick cuticle. They 

 are smaller in C. spicerianum than in C. villosum. In 

 both hybrids the length is between those of the parents, 

 though in C. lathamianum it is much nearer C. villosum, 

 and in C. lathamianum inversum nearer C. spicerianum. 

 The width in the hybrids is greater than in either parent. 

 (Table J 54.) 



Hairs are present at the top of the flower-stalk. 

 They are long and pointed in C. spicerianum; equal 

 numbers of club-shaped and pointed hairs in C. villosum; 

 all pointed in C. lathamianum; and only 1 in 25 club- 

 shaped in C. lathamianum inversum. In this character 

 both hybrids seem to resemble C. spicerianum more than 

 C. villosiim. There are 2 hairs in a field in C. spiceri- 

 anum No. 1 and 6 in 10 in No. 2 ; 2.7 in C. villosum; and 

 2.1 in C. lathamianum inversum. The pointed hairs are 

 shorter in C. spicerianum than in C. villosum, and in 

 length in the hybrid are between those of the parents, 

 though much nearer C. spicerianum than C. villosum. 

 The club-shaped hairs are present only in C. villosum 

 and C. lathamianum inversum, and are very nearly as 

 long in the latter as in C. villosum. (Table J 54.) 



The top of the flower-stalk in C. spicerianum is hairy, 

 and brownish purple due to all of the epidermal cells, 

 except those from which the hairs arise, being filled with 

 deep-violet cell sap. The hairs contain orange chromo- 

 plasts. (In C. spicerianum No. 2 the flower-stalk is 

 greenish purple at the top, and only slightly hairy. The 

 color is due to a few cells and a few of the basal cells 

 of the hairs containing violet sap, the others containing 

 pale-green plastids.) In C. villosum the color is green, 

 with many purple and colorless hairs, due to cells con- 

 taining green plastids, others with violet sap and yellow 

 chromoplasts. All of the hairs contain yellow chromo- 



