1901] Leavitt, — Embryology of Orchids 61 
NOTES ON THE EMBRYOLOGY OF SOME NEW 
ENGLAND ORCHIDS. 
R., G. LEAVITT, 
SPIRANTHES CERNUA.—In the December RHODORA I gave a 
brief account of polyembryony in this species. The embryos (Fig. 
1) are of vegetative origin and ecologically are to be 
classed with bulbils and tubers. It is noteworthy that 
the apparatus of fruit and seed-coats, which serves most 
plants for the dissemination of embryos sexually de- 
rived,is here put to the same use in the interests of 
the apogamous off-spring. The plant combines in this 
process the swiftness of seed-dispersal with the else- 
where slow, but always sure, methods of vegetative prop- 
agation. ; 
Heretofore Coe/eboyyne ilicifolia alone has been known 
to produce adventive embryos without the stimulus of 
pollination. With Spiranthes cernua, therefore, I took pains to 
Fig. 1 
determine whether pollen was needed to make the embryos grow. 
I took up a plant, which had lately sent up a flower-spike, on which 
only the six lower flowers were open. From these I drew out the 
pollinia. The remaining eight flowers were opened and their 
pollinia were removed with forceps ; the pollinia in every case were 
examined under a lens and found to be whole. In several cases 
the membranes surrounding the pollen-masses were brought away 
with the pollen. The potted plant was then placed under a bell-jar 
in the laboratory, where it was kept until the seeds were ripe; with 
the result, as already reported, that multiple embryos formed as 
. abundantly and grew to the same dimensions in all the pods as 
they do upon plants in the fields. 
Among orchids polyembryony of this type is known only in this 
species, I believe. Below will be noted instances in other New 
England species of the doubling of the embryo in the embryo-sac in 
the manner already described for several orchidaceous plants. 
When the sac and egg-apparatus develop normally, and the egg 
undergoes fertilization — a condition that I found in a few plants of 
this species — the resulting embryo within a very few days becomes 
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