PHANEROGAMIC LABOEATOBT STUDIES 249 



(See Rhodora, March and April, 1900 ; American Gardening, March 17 

 and 24, 1900.) — 2. The material is best preserved in alcohol. — 3. Many 

 herbaceous, geophilous plants show contraction. Examples must be 

 sought in the teacher's own locality. — 4. Grow seedlings in barely 

 moist sphagnum, in which saturated pieces of sponge are buried. 

 First sprout the seeds in water. Place them above and at one side of 

 the sponge or sponges, at varying distances and in different directions. 

 This experiment is suggested by Dr. R. H. True. — 5. With a fine 

 brush and India ink mark across the tip of the growing primary root 

 of a lately sprouted Bean, at intervals of 1 mm., for a distance of 

 1.5 cm. Put the seedling into a thistle tube, or glass funnel, with the 

 root running down into the tube. Over it place wet cotton, and cover 

 the top of thistle tube or funnel. Pest this apparatus in the mouth of 

 a jar or other receptacle containing a little water, the supporting jar 

 or bottle to be closed after the tube or funnel is admitted, so that the 

 water will not be lost by evaporation. In 24 hours, note the region 

 where elongation has taken place : measure the spaces. Repeat this 

 observation after 24 hours more. — 6. Place a young Tropseolum 

 plant under a bell jar, and leave for a day or two in a fairly warm 

 place. Drops of saj) are seen on the margin of the leaf. These are 

 forced up by "root pressure." (See Goodale, pp. 264-268, also 

 Chapter XVIII. of this book.) 



Chapter VII. Exercise XVIII. — Balsam (Impatiens) is better than 

 Begonia, though the latter is commoner in cultivation. Young shoots 

 of the Pipevine {Aristolochia Siplio) may be got at the proper season 

 and preserved for use. The Asparagus meant is the garden species, 

 the young shoots of which may be had from the market and preserved. 

 Indian Corn is equally good, or better. Permanently mounted cross 

 sections of both stems may be used. If the pupils cut their owm, the 

 scalpels must be very sharp, and should be wet when cutting. 



Exercise XIX. — This exercise may be omitted at the discretion of 

 the teacher. If taken, the block of wood may be of Oak, about 1| inch 

 in each dimension, cut so that two faces are at right angles to the 

 grain, two are vertical-radial, and two vertical-tangential in the tree. 

 The surfaces should be accurately cut in the given planes, and 

 smoothly finished. 



Exercise XX. — The Balsam is the best stem for this exercise ; it 

 may be had from greenhouses, or grown in the schoolroom from seed. 

 Other growing plants may be used. A solution of red ink may be 

 used, but is inferior to eosin (from supply companies). One ounce 

 eosin will color three quarts of water. 



Exercise XXI. — Experiment 9. The more freely the plant used is 

 growing, the better for this experiment. "Xasturtium" = Tropceolum. 

 On geotropism see Goodale and Strasburger, as before cited. — 

 Experiment 10. Other growing flower scapes may be found. The 



