Flowers on a completely self-impotent plant
of Passiflora alata fertilised with pollen from its own self-impotent
seedlings were quite fertile. Mr. Scott, and afterwards Mr. Munro, found
that some species of Oncidium and of Maxillaria cultivated in a hothouse
in Edinburgh were quite sterile with their own pollen; and Fritz Muller
found this to be the case with a large number of Orchidaceous genera
growing in their native home of South Brazil. (9/2. 'Botanische Zeitung'
1868 page 114.) He also discovered that the pollen-masses of some
orchids acted on their own stigmas like a poison; and it appears that
Gartner formerly observed indications of this extraordinary fact in the
case of some other plants.
Fritz Muller also states that a species of Bignonia and Tabernaemontana
echinata are both sterile with their own pollen in their native country
of Brazil. (9/3. Ibid 1868 page 626 and 1870 page 274.) Several
Amaryllidaceous and Liliaceous plants are in the same predicament.
Hildebrand observed with care Corydalis cava, and found it completely
self-sterile (9/4. 'Report of the International Horticultural Congress'
1866.); but according to Caspary a few self-fertilised seeds are
occasionally produced: Corydalis halleri is only slightly self-sterile,
and C. intermedia not at all so. (9/5. 'Botanische Zeitung' June 27,
1873.) In another Fumariaceous genus, Hypecoum, Hildebrand observed that
H.
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