- Apis mellifica Linn. Lake View, August 7. Seven specimens.
- Agapostemon texanus Cress. Lake View, August 7.
- Mellisoides bimaculata (St. Farg) Lepl. Lake View, August 7.
- Megachile petulans Cress. Lake View, August 7.
- Bombus separatus Cress. Lake View, August 7.
As in the case of Solanum, it will be seen that the collecting period extended over a very short period of time. More search would doubtless greatly increase the list.
Robertson reports the following species as collecting pollen: Bombus virginicus Oliv., B. separatus Cress., B. americanorum F., and B. scutellaris Cress.
August 28, when the blossoming season for C. chamæcrista was almost over, an examination of material from the above-named region was made for the purpose of determining the number of seeds produced by a single plant. Fifteen pods were selected at random from different plants and the number of ovules counted. It was impossible to tell about the number in each pod which were fully and normally developed seeds or which would become such; consequently this factor is not taken into consideration. The percentage of ovules which fail to develop is, however, small. The number of seeds found to the pod is shown by the following:
| TABLE F. | |||
| Pod I, | 13 | seeds. | |
| II, | 14 | " | |
| III, | 11 | " | |
| IV, | 11 | " | |
| V, | 10 | " | |
| VI, | 12 | " | |
| VII, | 16 | " | |
| VIII, | 12 | " | |
| IX, | 8 | " | |
| X, | 14 | " | |
| XI, | 17 | " | |
| XII, | 18 | " | |
| XIII, | 17 | " | |
| XIV, | 15 | " | |
| XV, | 14 | " | |
| Total XV, | 202 | seeds, | or 13.4 per pod. |
From this it will be seen that the minimum number of seeds found was 8, the maximum 18, with an average of 13.4. Since the pods were simply gathered at random, there is no certainty of gaining the maximum or minimum number of seeds, but a fair average of the number produced may be expected. September 4 three plants were examined to determine something about the range of variation in the number of ovules produced in the pods of a single plant. The results are given as follows:
- Plant 1 varies from 5 to 11.
- Plant 2 varies from 8 to 18.
- Plant 3 varies from 9 to 14.
- Plant 1 had 35 pods, plant 2 had 64, and plant 3 had 27.
- Plant 1 was selected on account of the small number of seeds produced per pod.
It will be seen from table D that an average of nearly 3.3 flower buds per cluster is produced. These were moderate-sized, healthy plants, producing on the whole probably more than the average number of clusters per plant. On the ten plants, there were produced 342 clusters, which bore 344 seed pods, instead of about 1120, the number of flowers which might be expected, thus giving less than thirty-three per cent. of the buds which produce mature seed pods.
It will be seen that, while in the observations made on S. rostratum the flowers which failed to produce seed did not reach much over six per cent., in C. chamæcrista it is over sixty per cent. In addition to this fact, it is rare to see a seed pod of S. rostratum which has been destroyed by insects or other destructive agencies, while in 460 pods of C. chamæcrista which were examined at Lake View, September 4, not one was found which did not have some of the ovules destroyed by the larvæ of some insect, and probably this would amount on the average to fifty per cent. of all the seeds produced, being in the case of some plants as high as seventy-five per cent.
A convenient method of approaching the question of the production of seeds might be to determine the number of seed pods produced on a given area of ground. A general idea may be obtained from the examination of the plants growing upon two square feet of ground. In the first case, the plants were much crowded; in the second, not nearly so much so; in fact, it may be said they were growing under “normal” conditions. It might be interesting to compare the results. The material for the two tables was taken September 4.