164 LABOR ATOBT STUDIES OF CRYPTOGAMS 



cium, with the attached portion of the thalkis. Wliere is the green 

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

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

 inner surface of the apothecium, and indicate these in the drawing. 

 The layer in which they occur is the hymenium. If possible, examine 

 this with a higher power, and draw an asciis (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. Is there a midrib? Examine the upper surface with the 

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

 much magnified, labeling the receptacle cupule, and the small bodies 

 within gemmcE. Are the gemmae easily detached? Put a drop of water 

 into one of the cupules and note the behavior of the gemmae? (The 

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

 absent.) What are the purpose and nature of the gemmae? 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 

 microscope 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 

 show all discernible details clearly. 



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

 of the thallus, ending in umbrellalike portions. Do you find more 

 than one kind, as regards the shape >of the "umbrella" ? If so, repre- 

 sent one sort in side view, " stalk " ai^ra|[|: - D?aw both of the " um- 

 brellas "as seen from above. The bfauc^^iding in free rays is to 

 be labelled archegonial branch., that ending in a lobed disk, antheridial 

 branch. 



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

 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 dehiscence (press the sporogonium slightly), 

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

 contain besides spores (use a high power) ? 



385 (CompStmd). The antheridial heads may be sectioned with 

 comparative ease, and the antheridia studied under the teacher's direc- 



