Physiological Anatomy of Xerophytic Selaginellas. 119 
Increase in Weight due to absorption-water after moistening for 
two hours. 
Condition 
Increase 
of weight 
Condition 
Increase 
of weight 
S. lepidophylla 
dead 
48*6% 
S. convoluta 
dead 
54-0% 
S. lepidophylla 
living 
51-0% 
S. imbricata 
dead 
52-5% 
5. pilifera 
dead 
42*0% 
S. Pringlei 
dead 
510% 
S. pilifera 
living 
45-0% 
S. longispicata 
dead 
472% 
S. cuspidata 
dead 
43-4% 
S. longispicata 
dead old 
S. cuspidata 
living 
46*0% 
S. iuvolvens 
stem 
dead 
40 0% 
47-2% 
Shoot apices (including fully developed shoot) 15 mm. in length 
were used for these experiments. An old stem of S. longispicata of 
the same length showed a slightly smaller increase. It will be 
seen that living plants absorb slightly more water than dead 
plants. 
The morphological and anatomical structure, especially of 
S. lepidophylla has been frequently discussed, e.g. by Hieronymus in 
Engler and Prantl “ Die Nattirliche Pflanzenfamilien ” (7), Lotsy 
(15), Neger (18), and others. Original investigations were 
conducted by Leclerc du Sablon (14) and especially by Wojinorvid 
(29). I have carefully examined the work of the two last authors 
and compared their results with related species. Some of the 
results are correct, but other very important deductions have 
proved to be misconceptions. 
WojinorviG states that the main axis of S. lepidophylla has a 
spiral form, due to a different development of one of the two shoots. 
This interesting account, can only be expressed to the best 
advantage in his own words : “ Die Entstehung dieser eigentiimliche 
Form der Axe ist morphologisch so zu erklaren, dass am Vegetations- 
punkte dichotomisch zwei Aeste angelegt werden, von denen der 
Rechte kraftiger wachst und strahlenformig nach Aussen abliegend, 
als Seitenzweig auftritt, der Linke dagegen stellt die Verlangerung 
der Stammesspitze dar und wachst, nicht in derselbe Ebene 
bleibend, langsam nach oben, indem er sich dabei gleichzeitig 
spiralig nach innen dreht.” 
Through repetition of this kind of growth, as explained above, 
the peculiar spiral arrangement of twigs round the axis takes place. 
I clearly observed the same principle in other Selaginellas, e.g., 
S. pilifera , S. Pringlei, S. involvens , S. cuspidata, and 5. longispicata , 
but was unable to find this development in S. imbricata. This 
characteristic seems peculiar to these species of Selaginella and 
has not been observed in other plants. 
