48 



LAWS OF FLORAL STRUCTURE 



tain, we shall here consider a special class of them, called Glands, not 

 only of great importance in diagnosis and classification, but of such 

 physiological importance that from that point of view they constitute 

 a distinct organ of the flower. For the peculiarities of structure and 

 secretory function of glandular tissue, works on histology must be 

 consulted. Here we note that although glands are sometimes distributed 

 through the other tissues in such a way as to be imperceptible on 

 superficial examination, their tissue is at other times collected into more 

 or less conspicuous bodies of definite form and position. The term 



"Gland" is frequently applied also to 

 bodies which resemble glands in location 

 and form, but which do not appear to be 

 glandular in function. Glands may be 

 stalked (Fig. 66, a), sessile (Fig. 67, a), 

 or depressed (Fig. 68, a, see Nectary), 

 and they may develop upon various parts 



Fig. 63. (a) frontal; (6) lateral, views 

 of base of petal of buttercup, showing a 

 scale which retain nectar in nectary. 

 64. Petal of Coptis, hollowed to form a 

 nectary. 65. Long hollow spur forming 

 nectary in fiower of Delphinium. 



Fig. 66. Stalked glands (a) on calyx of Dinemandra. 

 67. Sessile glands (a). 6S. (a) Depressed glands (nectary) 

 on petal of Frasera. 69. (a) Basal gland prevalent in 

 the Apocynaceae. 70. (a) Glands at base of stamen of 

 Sassafras. 



of the flower or plant. Those upon the outside of the calyx are exten- 

 sively utilized in classification in the family Malpighiaceae, while those 

 upon the inside are so used in the families Apocynaceae (Fig. 69, a) and 

 Gesneriaceae. 



Fig. 68 is an illustration of glands located upon the corolla, while 

 Fig. 70, a, illustrates them connected with the stamens, as seen in 

 Sassafras. 



Glands upon filament-like stalks, suitably located, may easily be 

 mistaken for stamens. Glands may be themselves appendaged. 



As to their origin, it may be stated that glands frequently result 



