LABOBATOBY STUDIES OF CBYPTOGAMS 165 



tion. Good preparations of the archegonia, from which the sporogonia 

 originate, are more difficult to make. If time allows, vertical sections 

 of the young archegonial heads may be made by the pupils ; or better, 

 the archegonia may be drawn from preparations provided by the 

 teacher. Distinguish the central egg cell, the neck and canal. 



386 (Simple). Moss. — Select a single plant, in fruit. Draw the 

 habit as seen with the hand lens. Examine w^ith the highest power 

 of the dissecting microscope. Is there distinction of leaf and stem? 

 Are the leaves petioled ? Have they midribs ? With needles clear 

 away the leaves at the j^oint where the stalk of the spore capsule 

 (sporogonium) originates. Does this stalk spring from the end of a 

 shoot of the moss, or is it a branch springing directly from the side of 

 a shoot? Is there any appearance of a joint or any mark around the 

 base of the stalk? Are the shoot and stalk separable? 



387 (Simple). Look for a capsule which still bears on its summit 

 a loose cap, the cahjptra. Draw the capsule, much enlarged. Remove 

 the calyptra. Examine the now exposed end of the capsule with a 

 strong lens. Do you find any appearance of a lid, or cover, by the 

 removal of which the capsule may be opened? Draw the outlines of 

 this part of the capsule, labeling the lid operculum. Slight pressure 

 may force the latter off. Teeth standing within the edge of the open- 

 ing may be seen. Xote the quantity and appearance of the spores. 



388 (Compound). With the compound microscope examine the 

 protonema of the moss, if this is provided, and draw a portion. Look 

 for buds, or beginnings of nev/ leafy shoots. 



389 (Simple or Compound). If ready mounted sections of the 

 flower, so called, are provided, the archegonia and anther id ia may be 

 studied under the teacher's direction. At least, the shoot tips bearing 

 these organs should be examined with a lens, and then dissected care- 

 fully with needles in a little water under the dissecting lens. By 

 skillfully removing the leaves that form more or less of a rosette 

 around the desired parts, and by further separation if necessary, 

 archegonia and antheridia may be distinctly seen, together with the 

 sterile filaments, or paraphyses, that grow up with them on the end of 

 the stem. 



390 (Simple). Fern. — 1. The prothalUiim. Place a young prothal- 

 lium on the stage of the dissecting microscope, without water. Ex- 

 amine rapidly with the lens. Are the upper and under surfaces alike? 

 Is the prothallium of equal thickness throughout? By what means is 

 the plant attached to the soil ? Add water. If soil particles still ad- 

 here, remove carefully with a small wet brush or with needles. The 

 general form reminds you of what cryptoganioas plant before studied? 

 In what respects (refer to former drawings)? Which is the younger 

 extremity of the prothallium? 



Turn it under side upwards and view by transmitted light. Draw 



