Journal of Heredity. 13 (7): 369-373 (July 1922)
A. B. Stout
New York Botanical Garden, New York City

A fine large cluster of L. croceum, all descended from a single bulb, growing in the New York Botanical Garden, completely failed to set seed for eight consecutive years. The numerous flowers that appeared each year were self- and cross-pollinated, but there was never even a slight enlargement of any of the ovaries. In 1921, plants of L. elegans bloomed at the same time as the cluster of L. croceum, and their pollen was used in pollinations. Fine large pods then developed, and these contained many viable seeds. In 1922 these plants of L. croceum also yielded pods and seed by cross-pollination with another strain of the same species. Hence these plants were fully able to mature fruit, and their pollen was likewise able to function in certain reciprocal crosses.

Capsules also failed to form when pollen of such species as L. canadense, L. supurbum, L. henryi, L. speciosum, L. auratum, and L. humboldtii was used. To pollen of L. warleyense, the ovaries of the Tiger Lily began to enlarge and become upturned, but the capsules did not develop fully and yielded no seeds. But when pollen of L. maximowiczii was used fine pods were readily obtained.

The phenomena of incompatibility are well illustrated by the results obtained with L. regale, a splendid and beautiful lily recently introduced from China. Of the ten plants tested, nine were self-incompatible and one was self-compatible. Cross pollination between plants sometimes succeeded and sometimes failed. The same sort of results were also obtained with plants of L. speciosum, L. candidum, L. henryi, L. parvum, L. tenuifolium, L. humboldtii, L. kelloggii, L. warleyense, L. longiflorum, and L. auratum.