48o 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8, 
on mountains 3,000 m. high and in the desert, showed no higher percentage 
of pollen with starch than the plants growing under the favorable climatic 
conditions of the tropical rain forest. He does, however, observe that there 
is frequently a difference in starch content between mature and immature 
grains. 
Lidforss (1899, p. 306) reports the analysis of sixteen varieties of pollen 
for nitrogen and P2O5. Of these, 11 were from anemophilous, and 5 from 
entomophilous flowers. He found the average nitrogen content of the 
wind-carried pollen to be 4.63 percent, while that of the insect-carried 
pollen was 7.49 percent. The P2O5 showed a similar difference; the average 
for the former pollen being 1.76 percent, and for the latter 3.03 percent. 
Whether or not this represents a real correlation must be established by 
further observations. 
The relative amounts of protein, fat, sugar, ash, etc., can best be seen 
by comparison of tables 1-7. It is interesting to note, from Stift's analyses 
of the pollen of three varieties of Beta vulgaris, that the different constituents 
may vary considerably in the pollen of one species (Stift, 1896, p. 43; 1901, 
pp. 105-106). 
Table i. Comparison of Pollen Analyses {figures indicate percentages) 
Kind of 
Pollen 
Authority 
Protein 
Fat 
Ash 
Carbohydrates 
Date palm . . 
Vauquelin, 
Ca3(P04)2 
1802 
Mg3(P04)2 
Cat tail 
Braconnot, 
3.60 
Starch Sugar 
1829 
Cypress .... 
Church, 
1875 
8.67 
1.87 
370 
85.76 
Hazel 
Planta, 
30.06 
4.20 
3.81 
5.26 14.7 
1885 
Saccharose 
Pine 
Planta, 
1885 
16.56 
10.63 
3-30 
7.06 11.24 
Pine 
Kressling, 
1891 
15.87 
10.00 
5.50 
7.40 12.075 
Pentosans 
Beet 
Stift, 1896, 
16.90 
3-52 
9.18 
0.89 12.26 
Rye 
1901 
16.68 
547 
7.13 
0.89 7.27 
Kammann, 
1912 
40.00 
3.00 
340 
25 
Dextrin Sugars 
Ragweed . . . 
Heyl, 
24.40 
10.80 
5.39 
2.10 2.10 
1917 
Pentosans 
7.26 
Ragweed . . . 
Koessler, 
1918 
8.25(?) 
10.30 
10.60 
6.89 
Stoklasa (1896, p. 631) analyzed the pollen as well as various other 
organs of apple, horse chestnut, and beet, and concludes: 
Das lecithinreichste Organ der ganzen Pflanze aber ist entschieden das Pollenkorn. 
He found in apple pollen 5.86, in that of horse chestnut 5.16, and in that 
of beet 6.04 percent of lecithin. Heyl (1919 a, p. 672) discusses the chemical 
"building stones" from which the substance of pollen sperm nuclei may be 
