178 



ORGANOGRAPHY. 



Fig. 35: 



Fig. 358. 



Fig. 857. A portion of the stem ?•, and leaf/, of the Astragalus Onobrychig. 



s. Syuoclireate or opposite stipules Fig.u'tS. A portion of the stem r, 



&ndi l^iS f, oi Houttiajnia cordata. s. Axillary stipule. 



outer and inner margins so as to form a sheath which encircles 

 the stem above the leaf {fig. 254), as in the Rhubarb, and most 

 Polygonacerc, they form what is termed an ochrea or intrafoliace- 

 ous stipule. All the above forms of stipules occur in plants with 

 alternate leaves, in which these appendages are far more com- 

 mon than in those with opposite leaves. When the latter have 

 stipules it generally happens that these are situated in the in- 

 tervals between the petioles on each side, and are hence termed 

 interpetiolar. In such cases, one of the stipules of each leaf on 

 the two sides of the stem frequently cohere by their outer 

 margins more or less completely, so as to form but one inter- 

 petiolar stipule on each side of the stem {fig. 359), as is the case 



Fig. 359. 



Fig. aw. A portion of a branch r, with two opposite leaves //, of Cephalan- 

 thus occidental is. s. Interpetiolar stipule. 



in the Cinchonas, the Coffee, and other plants of the order to 

 which tlicy belong. 



Stipules, as we have already noticed, are not always present 

 in plants, but their ]tre.scncc or absence in any particular plant 

 is always regular, and although the api)earancc and arrange- 



