1893.) The Tendrils of Passiflora. 129 
_ the straight tendril will pass the curved portion without touch- 
ing, and catch the hooked end of the short arm with its curved 
tip. Any tension set up is indicated directly on the scale. 
The tendrils tested with this type of dynamometer exhibited 
tensions of 3 to 10. 
The function of the tendril is doubtless to pull the growing 
shoot up toward the light and fix it to a support. It occupies 
4 supra-axillary position and the internodes are from 3 to 10™ 
in length. The work of each tendril as it in succession comes 
‘maturity is to lift its internode and the undeveloped inter- 
nodes of the growing shoot. On testing it was found that 
this portion of the plant never reached a weight of 1%, 
and the amount to be lifted by two adjoining tendrils rarely 
pees ts". Thus it will -be seen that each tendril is 
‘apable of doing the work of many. The value of this pro- 
"sion is apparent when it is known that not all of the ten- 
drils are able to reach supports, others are injured or rendered 
Hg able of grasping objects by the force of the winds, and 
t the firmness with which a plant is held has a direct in- 
Ce on its growth, 
eae coiling of the attached tendrils and the subsequent 
engthening ; ; 
sig without 
OM its Supports must . 3 is 
ture the ten aril first straighten the coils and then rup 
inj 
te. 
; » the tendrils and terminal internodes of 
P€cies of Passi 
s ae sy a uitive to contact of solids, and liquids at a 
dinary and ote ee and are non-sensitive to liquids at or- 
duce direct » “mperatures, unless they are so applied as to 
oe ling around Pb action, and to slight electrical stimuli. 
De of spirals ¢ N object takes place on contact, while forma- 
— Pitals ex. akes Place On maturity. The formation of the 
RE the tendril tension of three to twenty grams, shorten- . 
: “2 Withsta d one third of its length, and a mature tendril 
 Ougy, z * strain of 350 to : 
. “periment Station, La Fayette, Indiana. 
