38 



STRUCTURAL BOTANY. 



the Poplar and Willow, or altogether disappears, as in the Birch. 

 Ash, and Lizard-tail (15, 16). 



106. Setae, meaning bristles in general, is a term specifically 

 used to denote the reduced perianth of the sedges. In the Bog- 

 rush (Scirpus) there is, outside the stamens, a circle of six setze, 

 representing a 6-leaved perianth (78). In the Cotton-grass 

 (Eriphorum) the setae are multiplied and persistent on the fruit, 

 becoming long and cotton-like. 



107. Perigynium is the name given to the urceolate perianth 

 of Carex, investing the ovary but 



allowing the style to issue at its sum- 

 mit. It is composed of two united 

 sepals, as indicated by the two teeth 

 at the top (79). 



108. Glumes and pales repre- 

 sent the floral envelopes, or rather 

 the involucre of the Grasses (436). 

 Their alternating arrangement clearly 

 distinguishes them from a perianth. 



109. The duration of the calyx 



i . . * i i i 78, Flower of Scirpus lacnstris, tnagiit- 



anCl COrOlla Varies Widely, and IS fled 4 , consisting of six setae, three stamens, 



" three pistils united, except the stigmas. 



marked by certain general terms. 79, Flower of carex rivuiaris $ , with g , 



. 11 its glume, 77, its bottle-shaped perigrynium, 



it IS CaaUCOUS When it lallS Off im- 2-toothed. at top, enveloping the triple 



ovary; stigmas, three. 



mediately, as the calyx of Poppy, 



corolla of -Grape; deciduous when it falls with the stamens, as 

 in most plants ; and persistent, if it remain until the fruit ripens, 

 as the calyx of Apple. If it continue to grow after flowering, it 

 is accrescent ; and if it wither without falling off, it is marescent. 



Review. 99. Primary distinctions in the forma of the perianth. 100. Four forms of 

 polypetalous-regular perianths. To which belongs Stock? Pink? Apple? Lily? 101. 

 Two forms of polypetalous-irregular describe. Explain figs. 59-61. 102. Name tha 

 Beven forms of gamopetalous-regular. To which belongs fig. 62 ? 68 ? 64 ? 65 ? etc. The 

 flowers of Elder ? Kalmia? Harebell? 103. Describe the gamopetalous-irregular foims, 

 etc. 104. What is aus ? Describe the figures 72-77. 106. Perianth of Bog-rush 107. 



out the glumes The pales. 109. Define caducous- 



78 



Deciduous Accrescent Marescent. 



