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A TEXTBOOK OF 'I'HEORETICAL BOTANY 



There is a widespread belief that true lateral stipules are altogether wanting 

 in the Monocotyledons, but Gli'ick has shown that genera in several families, 

 notably Hydrochoris, Potaniogeton, and Diuscorea possess free lateral out- 

 growths of the leaf sheath which must be accepted as stipules. 



A 



D 



Fig. y79. — Various types of stipules. A, Boehnieria nivea ; axillary stipules. 

 B, Alchemillo vulgaris ; antidromous stipules. C, Euphorbia peplis ; inter- 

 petiolar stipules. D, Lotus cuniicu/atus; pseudo-stipules. E, Polygonum hydro- 

 piper ; ochrea. F, Hydrocharis niorsus-ranae ; monocotyledonous stipules. 

 (A to C after Gl/ick ; D /o F ajter Velenovsky.) 



In Dicotyledons examples of pseudo-stipules are not uncommon, 

 especially in genera with compound leaves, such as Cohaea and Vicia, in 

 which the lowest pair of leaflets may develop so close to the leaf base that 

 they simulate stipules and may even envelop the stem. Pisum is apparently 

 the reverse case, where true stipules become enlarged until they appear to 

 be the lowermost pair of leaflets. 



Pseudo-stipules may arise in a variety of ways other than by modification 

 of basal leaflets. They may, as in Cestrum for example, be the paired basal 

 leaves of an axillary shoot. In the simple leaves of Vibuiniim opiilus, the leaf 



