172 SYSTEMATIC BOTANY. 



noted, and then those of the pistil as follows number of the constituent 

 carpels, their isolation or cohesion and arrangement, their adhesion and rela- 

 tive position, form, cavities, partitions, and mode of placentation. The styles 

 require to be noted with reference to their position, number, size (relative 

 and absolute), form, surface, colour, &c. Similar remarks apply to the 

 stigma. The ovules differ in their position, mode of attachment, number, 

 form, &c. The fruit follows the same rules as the pistil ; but, in addition, 

 the texture, mode of dehiscence, and number of seeds must be noted. 



Seeds are described much in the same way as ovules, taking- care not 

 to overlook any of the peculiarities presented by the coverings of the seed 

 in the way of hairs, scales, arils, and the like : the interior of the seed also 

 requires special attention, to see whether or not it be albuminous or exalbu- 

 minous ; if the former, the nature and quantity of the albumen should be 

 noted ; and in any case, where possible, the form, position, direction, size of 

 the embryo and its parts, the nature and number of the cotyledons, &c. 

 should be accurately ascertained. 



The student is recommended to take any plant he meets with, and 

 endeavour to draw up a description of it with reference to the foregoing 

 scheme. By comparing- the description of one plant with that of another 

 he will familiarize himself with the main points of difference between one 

 plant or one organ and another, and will learn to apply the appropriate 

 term to each modification. 



The subjoined description of the common white Dead-Nettie (Lamium 

 album) is given as an illustration of a tolerably complete description of 

 the external peculiarities of a plant ; it may serve as a model to the 

 student in drawing up similar descriptions. It is, however, advisable that 

 he do not attempt too much at once. A bad or careless description is 

 almost worse than none at all ; hence the beginner is recommended to 

 make himself pretty thoroughly acquainted with the peculiarities of such 

 organs as are most easily studied before passing on to organs such as 

 ovules, &c., which require some considerable practice before their structure 

 and characteristic features can be ascertained. 



Lamium album. A rather coarse hairy perenmal,with a shortly creeping 

 stock, from the joints of which, especially on the lower surface, proceed at 

 intervals numerous slender, fibrous, brownish roots. Stems 1-2 feet high, 

 herbaceous, decumbent or ascending, fistular, four-sided. Leaves exsti- 

 pulate, opposite, stalked, the upper ones nearly sessile, hairy, membra- 

 nous, ovate-acute or acuminate, cordate, coarsely and irregularly toothed, 

 unicostate, arch- veined, 2-3 inches long, 1-2 inches broad. Petiole less 

 than half the length of the blade, channelled on the upper surface, rounded 

 beneath. Flowers pure white, sessile, in axillary cymose whorls (verti- 

 cillasters) of 6-10 or more. Calyx campanulate, of o sepals, united below 

 into a tube traversed by 10 ribs ; limb divided above into five nearly equal, 

 spreading, linear, ciliated segments, of which the uppermost stands slightly 

 apart from the others. Corolla white, tubular, bilabiate, twice the length 

 of the calyx ; tube curved, ventricose, as long as or longer than the calyx, 

 scabrous inside, with a ring of hairs near the base ; upper lip erect, concave, 

 notched, hairy on the outer surface ; lower lip spreading, 3-lobed, the 

 middle lobe broad and 2-lobed, the two lateral ones small and pointed. 

 Stamens 4, didynamous, epipetalous ; filaments downy, springing from the 

 upper part of the tube of the corolla, partially concealed within the upper 



