60 INTRODUCTION 
Pontederiaceae : Heteranthera (not Monochoria) Kotschyana /2/., H. reniformis, 
H. spicata, H. callaefolia, H. Potamogeton, and other sp. (Solms-Laubach). 
Commelinaceae: Commelina bengalensis (Weinmann), Tradescantia erecta 
(Henslow). | 
Juncaceae: Juncus (Darwin), J. capitatus (Buchenau), J. pygmaeus (?, Buchenau). 
Gramineae: Hordeum (Darwin), H. vulgare (a few flowers, Delpino), Crypto- 
stachys (Darwin), sp. of Stipa (Godron), St. pennata (Hackel), sp. of Bromus (Bei- 
jerinck), Leersia oryzoides (Duval-Jouve, Ascherson, Kiefer), Amphicarpum, Danthonia 
spicata and related sp. (Pringle and Asa Gray), Vilfa (Pringle), Diplachne serotina 
(Janka and Hackel), Vulpia Myuros, sciuroides, and ciliata (Kiefer). 
Connected with cleistogamy is the so-called bud-fertilization, cases of which 
have been more particularly observed in orchids, e. g. in Limodorum abortivum 
(Freyhold), Thelymitra carnea and longifolia (Fitzgerald), Polystachya luteola 
(E. Eggers), Polystachya zeylanica, Phajus villosus, and Calanthe inaperta (Moore), 
Maxillaria rufescens (Reichenbach fil.). 
Vil. Parthenogenesis. 
A few remarks may here be introduced concerning Parthenogenesis (virgin 
reproduction) of flowering plants. The term signifies she formation of germinable 
seed without the aid of pollen, It is well known that the first observation on this 
phenomenon was published by J. Smith (Trans. Linn. Soc., xxi, 1841, p. 509): 
A female plant of the dioecious species Caelebogyne ilicifolia, grown in the Botanic 
Gardens at Kew, from 1829, produced seed capable of germinating, necessarily 
without previous fertilization. A. Braun, by examining a cultivated plant in the 
Botanic Gardens at Berlin, established the correctness of Smith’s observation and 
compared the phenomenon with the parthenogenesis of insects discovered by 
Th. v. Siebold (1856). Deecke, indeed, observed individual pollen-tubes, while 
Baillon and Karsten saw isolated anthers in the otherwise purely female flowers, 
but A. Braun’s further observations (‘Uber Polyembryonie und Keimung bei Caelebo- 
gyne,’ Berlin, 1860) contradicted those of the botanists named. It was only in 1878 
that Strasburger (‘Uber Polyembryone,’ Jenaische Zs. Natw., xii, 1878) cleared up the 
matter by proving that this case finds an analogue in the occurrence of so-called adven- 
titious embryos, e.g. in Funkia ovata, Allium fragrans, Euonymus latifolius, sp. of Citrus, 
and others, in which individual nucellar cells in the neighbourhood of the embryo-sac, 
grow into this as rounded bodies, that multiply by cell-division and develop into 
adventitious embryos without the direct influence of fertilization. In Caelebogyne the 
proliferating nucellar cells, which are growing into adventitious embryos, press upon 
the disorganized egg-apparatus. This case, therefore, differs from the other only 
in the complete suppression of fertilization, but is in complete agreement with it, 
so far as concerns the development of adventitious embryos independently of fertiliza- 
tion, And this proves that the embryo-production in Caelebogyne is not really 
parthenogenetic, though further development takes place of an egg-nucleus that 
remains unfertilized. It represents, on the contrary, a process of asexual reproduc- 
tion, similar to the apogamy of many ferns, or the vivipary in spikelets of grasses 
(Loew, ‘ Einfiihrung in die Bliitenbiologie,’ p. 296). 
