116 HOEPHOLOGY, OE COMPAEATIYE ANATOMY. 



Perianth of Palms. The perianth of the Palms, of Juncaceae (fig. 

 210), and other Monocotyledons is composed of scale-like, fleshy or mem- 

 branous organs, either free or confluent, approaching to the condition 

 found in the Glumiferae. 



Monochlamydeous Perianth. The perianth of the Mono- 

 chlamydeous Dicotyledons is very varied in form, texture, and 

 colour. It may be gamophyllous or polyphyllous, and then regular 

 (fig. 211) or irregular (fig. 212), and, moreover, petaloid or sepaloid. 

 It is reduced to the lowest state in the Poplar (fig. 213), where it 

 is a mere membranous cup ; and it is absent in the allied genus 

 Salicc, as also in the Ash (fig. 214), which are therefore achlamy- 

 deous. 



Fig. 212. 

 Fig. 211. 



Fig. 213. 



Fig. 211. Eegular perianth of Asarum. , 

 Fig. 212. Irregular perianth of Aristolochia Clematitis. 



Fig. 213. Flower of the Poplar: <J, from a male catkin; ?, from a female catkin; each 

 with a cup-shaped perianth. 



A gamophyllous, coloured, regular perianth exists in Thymelacese 

 (Daphne) ; the dull-coloured gamophyllous perianth of Aristolochia is 

 irregular (fig. 212). The gamophyllous sepaloid perianths of Ulmus and 

 Castanea (figs. 215, 216) &c. are regular j the polyphyllous sepaloid pe- 

 rianth of Urticaceae is also regular. In Polyyonum, the regular gamo- 

 phyllous perianth is partially petaloid, while,' in the same order, Ruinex 

 and Rheum have a double circle of unequal, wholly sepaloid organs. 



Glumaceous Perianth. The perianth of the Glumiferous Mono- 

 cotyledons requires special mention. 



In the Grasses, as already mentioned, the flowers are borne in spikelets, 

 associated in spikes, or panicles. A spikelet of the Oat, for example 

 (fig. 217), exhibits at its base a pair of green membranous bracts, the 

 glumes (a, a) more or less enclosing all the inner parts : these are regarded 

 as bracts, or spathes ; and within them are found one, two, or more 

 flowers.^ The flowers succeed one another alternately on a rachis ; and 

 each is invested by a bract resembling the glumes, called the jftowerinff 

 glume or the outer paka (figs. 217-219, b) : within this is an inner scale 



