204 PHILOSOPHICAL NOTES ON 



In the Zea Mays (Indian corn) the female spike of flowers is 

 enveloped in a great number of these enlarged stipules, the blade 

 of the leaf being entirely abortive or partially so, as in many 

 American varieties of Zea. The so-called bracts of the young 

 bamboo shoot, like the bracts of the maize cob, are only vaginas of 

 leaves, without the blades, or we might call them enlarged glumes 

 or bud-scales. 



The sheath at the base of the Arad leaf appears similar to that 

 of Sparganium, Fig. 63. And the flower -spathe of Calla 

 Ethiopica and others is only a repetition of the same part, with the 

 blade undeveloped. 



If we consider the sheathing petiole, or the vagina of grasses 

 as two distinct stipules (or even one stipule) adnate to the petiole, 

 the ligules, as I said, fall into their natural places, as the/ree ends 

 of the stipules, and it will not be necessary, as Le Maout and 

 Decaisne have done, to consider the ligule " as an axillary 

 stipule, situated at the separation of the blade from the sheathing 

 petiole.^'' 



I said that the vagina of grasses might have originated in 

 either one or two stipules, because in certain species of Ficus 

 we find two separate stipules and in others only one, as in 

 F. elastica. The latter may no doubt be the union of two 

 originally separate ones, or the former may be the spHtting up of 

 one originally undivided stipule. The spathe of Calla, of Anthuriinn, 

 and of other Arads may have originated in stipules such as that 

 which ensheathes the terminal bud of F. elastica. The 

 invaginating base of the leaf of many umbelliferae may be 

 considered as ha\^ng the same origin. 



Can we now follow the stipule a little further, and discover 

 how it originated in the first instance ? We have, in a way, been 

 able to see that the stipule of Potatnogeton, the ochrea of Poly- 

 gonum, the vagina of grasses, and therefore of sedges, and their 

 glumes, and the flower-spathe of Calla, Amaryllis, and others are 

 all homologous parts, but can we trace the origin of the stipule 

 further ? 



In text books, stipules are said to be appendages of leaves, but, 

 if we reverse matters, and call the leaf an aj^pendage of the 

 stipule, we may perhaps be nearer the truth. Let us endeavour 

 to make a rough survey of the different kinds of stipules. 



