CHAPTER VII 



THE TORUS 



Review. — The fundamental principles of anthology are based upon 

 the nature of the torus as a modified branch. We have already con- 

 sidered the evidences of this fact depending upon its position and the 

 relative positions of the parts developing upon it. We shall now con- 

 sider some which depend upon its modifications. These are in part 

 permanent and typical and in part exceptional and abnormal. 



Elongation of the Intemodes. — Among the latter we note that in those 

 frequent cases in which the parts of flowers revert to the leaf condition, 

 the torus often elongates, separating the floral series exactly as whorls 

 or spirals of leaves are separated by the internodes upon a branch. At 

 other times, the torus will be continued beyond the apex or center of 

 the flower in the form of a leafy branch. Occasionally one of the sepals 

 will be found at its proper radial point, but vertically distant from the 

 rest of the calyx, a portion of the flower stem intervening. 



The Anthophore. — A similar condition, but affecting an entire series, 

 normally characterizes certain species, or groups of species. The 

 elongation may affect any internode or internodes. When (Fig. 246, a) 

 it is between calyx and corolla it is called an Anthophore. Sometimes, 

 as in Viscaria (Fig. 248), the anthophore may be very slight, so as to 

 escape detection until a longitudinal section reveals its presence. 



The Gonophore. — A similar elongated portion between corolla and 

 androecium is a Gonophore (Fig. 249, a). 



The Gynophore. — One between androecium and gynoecium (Fig. 249, 

 b, and Fig. 252, a) is a Gynophore. A thecaphore (Fig. 9) often resembles 

 a gynophore and may be mistaken for it. The point of articulation and 

 separation at maturity will determine whether the stalk is a portion of 

 the ovary (thecaphore) or of the torus (gynophore) . 



The Carpophore.— A slender extension of the torus upward among the 

 carpels, which are attached to it, constitutes the Carpophore, as in 

 Erodium (Fig. 245). The presence of a carpophore is characteristic of 

 plants in the Umbelliferae (P'ig. 247). 



The Gynobase. — In the Boraginaceae the carpophore is frequently 

 reduced to a pyramidal or conical form, or is shortened or laterally 



