822 



MACROSCOPIC AND MICROSCOPIC CHARACTERS OF PLANTS. 



plasts which become orange-brown in the end-cells. 

 Nearly all the hairs contain deep-violet sap. In C. 

 lathamianum the color is green with shorter hairs and 

 purple specks, due to some cells containing yellowish- 

 green plastids, others, 2 or 3 together, with violet sap 

 and yellow chromoplasts, these being in much greater 

 number than in C. villosum; hairs have yellowish-green 

 plastids" and a violet sap. In C. lathamianum inversum 

 the color is a lighter green, with short purplish hairs, the 

 color being due to the same causes as in C. lathamianum, 

 but there are fewer cells with violet sap grouped together. 

 The epidermis at the middle of the flower-stalk con- 

 sists of thin-walled, rectangular cells with a thick outer 

 cuticle. They are smaller in C. spicerianum than in G. 

 villosum, and in width are between those of the parents 

 in both hybrids, though nearer C. villosum. In length, 

 that of C. lathamianum is greater and that of C. lathami- 

 anum inversum less than in cither parent. (Table J 54.) 



TABLE J 54. 



Hairs similar to the foregoing are present at the 

 middle of the flower-stalk. Pointed hairs only are pres- 

 ent in C. spicerianum; twice as many pointed as club- 

 shaped hairs in C. villosum; many pointed and very few 

 club-shaped hairs in C. lathamianum; and pointed with 

 many club-shaped hairs (more than in C. villosum) in 

 C. lathamianum inversum. In the number of club- 

 shaped hairs C. lathamianum is very nearly mid-inter- 

 mediate between those of the parents, but the number in 



C. lathamianum inversum goes beyond that of either 

 parent. 



Hairs number 2.3 in C. spicerianum, 3.1 in C. vil- 

 losum, 2.9 in C. lathamianum, and 3.7 in C. lathamianum 

 inversum. In C. spicerianum No. 2 hairs are very much 

 less numerous and shorter than in C. spicerianum No. 1. 

 The pointed hairs are shorter in C. spicerianum than in 

 C. villosum, and in length in the hybrids between the 

 parents, but nearer C. spicerianum than C. villosum. The 

 club-shaped hairs are only slightly shorter in both hybrids 

 than in C. villosum. 



The color is the same at the middle -as at the top of 

 the flower-stalk, except in C. spicerianum No. 2 where 

 it is a dark purple, due to most of the cells being filled 

 with violet sap and yellow chromoplasts. Other cells 

 contain only yellow chromoplasts, and a very few color- 

 less hairs are present. 



Transverse sections of the flower-stalk were taken at 

 a point midway between the top and the base. Outer- 

 most is a layer of epidermis that consists of rounded cells 

 with slightly thickened inner and lateral walls and a 

 greatly thickened outer wall. The outer wall is ridged 

 in all of the plants, and it is thicker in C. spicerianum 

 than in C. villosum, and thicker in both hybrids than in 

 either parent. From this layer arise the hairs. The 

 epidermal cells themselves are smaller in C. spicerianum 

 than in C. villosum, and are in botJt hybrids between 

 the parents in size, except for the depth in C. lathami- 

 anum which is less than in either parent. The depth in 

 C. lathamianum inversum is nearer that of C. villosum. 

 The width in C. lathamianum is almost exactly mid- 

 intermediate between the widths of the parents; in C. 

 lathamianum inversum, however, it is nearer that of 

 C. villosum. (Table J 54.) 



Beneath the epidermis are several layers of thin- 

 walled, rounded cells containing green chloroplasts, the 

 cortex, with the walls of the outermost layer slightly 

 thickened. This zone is 6 to 8 rows deep in C. spiceri- 

 anum, 10 to 12 in C. villosum, 8 to 10 in C. lathami- 

 anum, and 6 to 7 in C. lathamianum inversum, thus be- 

 ing almost exactly mid-intermediate in C. lathamianum 

 and the same or less than in either parent in C. lathami- 

 anum inversum. The cortex is not as wide in C. spiceri- 

 anum as in C. villosum, and it is between the parents 

 in both hybrids, being exactly mid-intermediate in C. 

 lathamianum and nearer C. spicerianum in C. lathami- 

 anum inversum. (Table J 54.) 



Within the cortex is the vascular cylinder, composed 

 outermost of several thickened layers of cells, and within 

 of rounded thin-walled cells in which are embedded the 

 bundles. 



FLOWER. 



Sections of the upper epidermis of the dorsal sepal of 

 the four plants were taken at the middle point along the 

 midrib. The cells are wavy-walled, slightly shorter but 

 wider in C. spicerianum than in C. villosum, but larger 

 in both hybrids than in either parent. (Table J 55.) 



Multicellular hairs are present on the upper epidermis 

 in C. spicerianum and the two hybrids, but absent in 

 C. villosum. (Table J 55.) They consist of from 3 to 5 

 cells linearly arranged, the lower cells being more elon- 

 gated, the upper more compressed and slightly swollen, 

 giving the hair a club-like appearance, the end cell being 

 rounded and containing a great many chromoplasts. They 



