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A TEXTBOOK OF THEORETICAL BOTANY 



suspensor may also occur, as in Capsella, and may show aggression, en- 

 croaching on the tissues of the inner integument. 



True haustorial outgrowths from suspensor cells were first noticed in 

 certain Orchids, e.g., Phalaenopsis and Stanhopea, and have since been found 

 in several other families. One of the most remarkable developments among 

 Orchids is found in Herminium monorchis. The extension in length of the 

 suspensor pushes its basal end out through the micropyle. The cells thus 

 exposed enlarge and send out numerous tubular haustoria which grow to a 

 great length. Treub describes these filaments, coming from all the fertilized 

 ovules, as forming an inextricable tangle involving the ovules and the 

 funicles and smothering the placenta. 



Fig. 1 35 1. — Tropaeohtm mojiis. Longitudinal sections of the carpel 

 showing, in black, successive stages in the branching of the sus- 

 pensor haustorium. A, In the ovule. B, In the carpellary cavity. 

 C, In the funicle and placenta. D, Detail of apex of the haus- 

 torial branch in the carpellary cavity. {After Walker.) 



