164 LABOEATORV STUDIES OF CRYPTOGAMS 



ciura, with the attached porlion of the tlinlhi';. Where is the green 

 color distributed? (Show iu drawing.) Distinguish small brown 

 bodies (spore sacs) standing in large numbers perpendicularly to the 

 inner surface of the apotheciuni, and indicate these in tlie drawing. 

 The Layer in which they occur is the hymeniura. If possible, examine 

 tills with a higher power, and draw an ascus (spore sac) with the (how 

 many?) spores. Also determine further the exact location of the 

 green color, and draw the green bodies. 



381 (Simple). Marchantia : a Liverwort. — Draw the outline of a 

 single plant, as seen from above, about twice the natural diameter. 

 Distinguish the growing tip and the base of the plant. Represent 

 the position and outline of any structures produced from the upper 

 surface. Ls there a midrib? Examine the upper surface with the 

 hand lens. What do the cup-shaped structures contain? Draw, 

 much magnified, labeling the receptacle cii/>uli', and the small bodies 

 within gemmce. Are the geinniaj easily detached? Put a drop of water 

 into one of the cupules and note the behavior of the gemma;? (The 

 gemmas are best seen on living plants ; in other material they may be 

 absent.) What are the purpose and nature of the gemmaj? By what 

 means are they likely to be disseminated? 



382 (Simple). Examine the upper surface of the thallus (plant 

 body) with the lens. Have the minute prominences pores at their 

 summits? It will be well to use also a low power of the compound 

 micrascope to settle this question definitely. Do the same promi- 

 nences occur on the under side of the thallus? By what means is the 

 plant attached to the ground? Draw a little portion of the upper 

 surface as seen by the hand lens, making the drawing large enough to 

 sliow all discernible details clearly. 



383 (.Simple). Turn your attention now to certain slender branches 

 of the thallus. ending in nnibrellalike portions. Do you find more 

 ilaxa. one kind, as regards the shape of the " umbrella " ? If so, repre- 

 sent one sort in side view, "stalk" and all. Draw both of the "um- 

 brellas" as seen from above. The branch ending in free rays is to 

 be labelled archegonial branch, that ending in a lobed disk, aniheridial 

 hranch. 



384 (Simple). Select a branch bearing well-matured sporoijonia. 

 Remove the stalk. Lay the head, under side upward, on the dissect 

 ing stage, and study the position of the sporangia. How are they 

 arranged, and to what are they attached? Note the fringed sheaths 

 that partly inclose them. Detach a sporogonium. Draw it to show 

 the form, the method of deliisoence (press the sporogonium slightly), 

 the relative length of the stalk, etc. What does the sporogonium 

 contain besides spores (use a high power) ? 



385 (Compound). The antheridial lieads may be sectioned with 

 comparative ease, and the an(/ier«7/a studied under the teacher's direc- 



