FOURTH GROUP. SEED-PLANTS. 



connected by short straight anastomoses into a lattice-like network, as in Alisma 

 Costus and Ouvirandra, in the last of which the mesophyll which is present in the 

 meshes of the young leaves is wanting in the older 1 . In a few cases only projecting 

 lateral veins proceed from the mid- rib and give rise to a delicate reticulated venation, 

 as in some Aroideae. 



FIG. 365. Floral diagram 

 ofScirpus (Cyperaceae). 



FIG. 366. Floral diagram 

 of Irideae. 



FIG. 367. Floral diagram 

 of Museae. 



FIG. 368. Floral diagram of Zingibereae. A Hedy- 

 chittni, after Le Maout and Decaisne. B Alpuria, 

 after Payer. 



FIG. 369. Floral diagram 

 of Canneae, after Payer. 



FIG. 370. Floral diagram of Alismaceae. 

 A Butomus, B Alisma. 



F'IG. 371. Floral diagram 

 of Triglochin (Juncagi- 

 neae). 



FIG. 372. Floral diagram 

 of Gymnestachys (Aroi- 

 deae), after Payer. 



The flower of the Monocotyledons usually consists of five alternating isomerous 

 whorls, an outer and an inner perianth-whorl, an outer and an inner staminal whorl, 

 and a carpellary whorl followed by a second only in the polycarpous flowers of the 

 Alismaceae and Juncagineae. The most common typical floral formula is therefore 

 Sn Pn Sin -f n Cn ( + n). The number of the staminal whorls is increased in the 

 Hydrocharideae only and in a few other cases ; where, as in Butomus, there is an 

 increase in the typical number of the stamens, this takes place without multiplication 

 of the whorls. The number of the members in a whorl is two only in some isolated 

 cases scattered through very different families, as 82 P 2 Si 2 + 2 2 in Maianihemum 

 and some Enantioblastae ; it is sometimes four or even five in Paris quadrifolia and 

 some Orontiaceae. The usual number of parts in a whorl is three and consequently 

 the typical formula is 3 P% St% + 3 3 ( + 3). 



Observed in specimens in the Botanic Gardens at Strassburg. 



