and Laboratory Methods. 2517 



glass or wooden rod approximately 15 cm. long is to be coated for half its length 

 with hot gelatine. When the gelatine on the rods has solidified, the rods are to 

 be kept free from dust by enclosing them in stoppered test tubes or bottles. 

 While the coats of gelatine are still soft, the tendrils of the passion vine (Passi- 

 fiora) are to be experimented with. First the concave side of the hook of an 

 uncoiled tendril is to be stroked gently three or four times with the gelatine coated 

 rod, and the tendril watched for three or four minutes for a response. If no 

 response is given, the test may be repeated with a naked rod. Determine in this 

 way the irritability of tendrils toward solid and non-solid bodies. What is the 

 biological significance of such a relation ? Determine also the latent period, 

 noting the temperature, the progressive coiling or straightening of the tendrils 

 after a very brief stimulation, the extent of sensitive surface of the tendril. 

 Part of the observation for the last topic named may be made on a plant whose 

 tendrils have already grasped supports. 



(c) Examine a woodbine (Ampelopsis) and find two kinds of climbing organs. 

 Discover the conditions for the formation of each kind. 



{d) -Find some plant, such as a cucurbit, whose tendrils make spiral coils. 

 Give a description of these coils, noting their various features. 

 University of Missouri. HOWARD S. Reed. 



Laboratory Outlines for the Elementary Study of Plant 



Structures and Functions from the Standpoint 



of Evolution. 



XLIV. (b) Ricciocarpus ?iata?is (L.) Corda. (Continued.) 

 7. Make a diagram in the notes as shown in Fig. 7, which represents the 

 general life cycle for all plants above the thallophytes. 



XLV. MarcJiantia polymorpha L. 



Class, Hepaticaj. Order, Marchantiales. Family, Marchantiaceae. 



This thalloid liverwort is common on moist rocks and earth, especially on 

 cliffs and around springs. Marchantia as well as Conocephalus and Lunularia 

 can be kept without any trouble in a greenhouse or window garden, provided 

 they are supplied with sufticient moisture and shaded from intense light by a 

 curtain. 



Gametophyte, 



1. Take a thallus (frond) and notice its dorsiventral position on the ground. 

 Make a naked eye sketch, showing the dichotomous branching, the central 

 groove, and the emarginate growing points. Describe. How is it fastened to 

 the ground ? How does the thallus continue its development .'' How is vegeta- 

 tive propagation accomplished ? 



2. Under dissecting microscope study the upper surface. Notice that it is 

 mapped off into diamond-shaped areas (areolae), each with a small opening in 

 the center (air passage). Draw a patch of the surface. 



