THE MONOPETALOUS ORDERS. 



447 



in the tropics, mostly trees ; one of which is the gigantic Indian 

 Teak (Tectona grandis), remarkable for its very heavy and dura- 

 ble wood, which abounds in silex. The leaves of the Aloysia 

 citriodora of the gardens yield an agreeable perfume. Others 

 are bitter and aromatic. 



839. Sllbord, ? Phrymacese (Phryma) is separated on account of 

 its simple pistil, uniovulate ovary, spirally convolute cotyledons, 

 and superior radicle. 



840. Ord, Labiatffi (the Labiate or Mint Family). Herbs, or 

 somewhat shrubby plants, with quadrangular stems, and opposite 

 or sometimes whorled leaves, replete with receptacles of volatile 

 oil. Flowers in axillary or terminal cy mules (412), rarely 

 solitary. Calyx tubular, persistent, five-toothed or cleft, or bi- 

 labiate. Corolla bilabiate. Stamens inserted on the corolla, 

 four, didynarnous, or only two, one of the pairs being abortive 

 or wanting. Ovary free, deeply four-lobed ; the central style 

 proceeding from the base of the lobes. Fruit consisting of four 

 (or fewer) little nuts or achenia, included in the persistent calyx. 

 Seeds with little or no albumen. Ex. The Sage, Rosemary, 



878 874 877 878 



Lavender, Thyme, Mint, &c., are familiar representatives of this 



FIG. 872. Flower of Glechoma hederacea, or Ground Ivy. 873. Approximate anthers of one 

 pair of stamens, magnified 874. Flower of aLamium. 875. Corolla of L. amplexicaule (Dead 

 Nettle) laid open, showing the didynamous stamens, &c. 876. Calyx and corolla of Scutellaria 

 galericulata (Skull-cap). 877. Section of the enlarged calyx of the same, bringing to view the 

 deeply four-lobed ovary, raised on a short gynobase. 878. Cross-section of a magnified ache- 

 nium. 879. Vertical section of the same, showing the embryo. 881. Flower of Teucrium 

 Canadense. 832. Magnified anther of the same. 883. Stamen of the Thyme. 884. Flower of 

 Monarda. 885. Magnified anther of the same. 886. Flower of a Salvia; the calyx as well 

 as the corolla bilabiate. 880. Magnified stamen of the same, with widely separated anther- 

 cells one of which (a) is polliniferous, the other (b) imperfect. 



