SHOWING MENDELIAN RESULTS. 293 
of contamination with the pollen of other kinds. АП the seed then was 
"selfed." The Huntingdon elm was the source both of the pollen and of the 
ovules *. 
Be best crop of Huntingdon elm-seedlings was raised in garden soil by 
". W. О. Backhouse +, one of my students. These seedlings, 971 in all, 
were counted as regards one character, and showed :— 
132 seedlings with opposite leaves. 
239 » „ alternate leaves. 
971 
——À 
The Mendelian ratio 3:1 is here closely followed, as the theoretica 
numbers are 732 : 244 (see Table 1, p. 298). 
А further examination of these seedlings showed that there were four 
kinds plainly visible in the bed, namely :— 
Ratio. 
Small, opposite-leaved  ..................... 9 (?) 
Large, " "NK 8 (?) 
Small, alternate-leaved .................... 8 (?) 
Large, " o ee e ese eel ens 1 (?) 
I have added here the theoretical ratio 9 : 3 : 3 : 1; but of this we are 
not certain, as it was impossible to count the seedlings, as regards two 
characters, without injuring them; and we wanted to preserve the whole 
стор. Mr. Backhouse considered that the 9 : 3 : 3 : 1 ratio probably existed 
in this lot of 971 seedlings. 
The production of these four forms is easily explained by the diagram 
(Table 2, p. 289). 
Another examination of these seedlings shows that some have leaves with 
e 
short petioles, whilst others have leaves with long petioles. This makes 
8 different kinds of seedlings. Taking into account the other points of differ- 
g g I 
ence on the two species, there are possibly 64 different kinds amongst the 
, 5 
* Knuth, ‘ Flower Pollination ’ (Engl. transl.) iii. 373 (1909) says :— The flowers in Ulmus 
are anemophilous and protogynous. The stigmas are mature when the flower opens and 
project beyond the anthers, which are still immature with short filaments. The latter 
elongate later on, so that the stigmas are hidden among the stamens; the anthers then 
dehisce ; and the stigmas, which are still receptive, may be fertilized by automatic self- 
pollination, if they have not been already dusted with foreign pollen. The flowers are in 
crowded clusters and do not mature simultaneously." Itis, I think, probable that in most 
cases each elm flower is fertilized by pollen from another flower of the same tree. 
T I may here express my indebtedness to Mr. Backhouse for help and suggestions in 
connexion with the experiments on the elms, and the explanation thereof. 
LINN. JOURN.— BOTANY, VOL. XXXIX, Y 
