

XXXVI OUTLINES OF ELEMENTARY BOTANY. 



it is to be found isolated, or almost isolated, in places where the two parents are abun 

 dant ; if there are two or three, they will generally be dissimilar from each other, one 

 partaking more of one parent, another of the other ; it seldom ripens good seed ; it will 

 never be found where one of the parents grows alone. 



Where two supposed species grow together, intermixed with numerous intermediate* 

 hearing good seed, and passing more or less gradually from the one to the other, it 

 may generally be concluded that the whole are mere varieties of one species. The be- 

 ginner, however, must be very cautious not to set down a specimen as intermediate 

 between two species, because it appears to be so in some, even the most striking cha- 

 racters, such as stature and foliage. Extreme varieties of one species are connected 

 together by transitions in all their characters, but these transitions are not all observ- 

 able in the same specimens. The observation of a single intermediate is therefore of 

 little value, unless it be one link in a long series of intermediate forms, and, when met 

 with, should lead to the search for the other connecting links. 



(2.) Accidental aberrations from the ordinary type, that is, those of which the cause 

 is unknown. 



These require the more attention, as they may sometimes lead the beginner far astray 

 in his search for the genus, whilst the aberrations above mentioned, as reducible more 

 or less to general laws, affect chiefly the distinction of species. 



Almost all species witli coloured flowers are liable to occur occasionally with them 

 all white. 



Many may be found even in a wild state with double flowers, that is, with a multi- 

 plication of petals. 



Plants which have usually conspicuous petals will occasionally appear without any 

 at all, either to the flowers produced at particular seasons, or to all the flowers of in- 

 dividual plants, or the petals may be reduced to narrow slips. 



Flowers usually very irregular, may, on certain individuals, lose more or less of their 

 irregularity, or appear in some very different shape. Spurs, for instance, may disap- 

 pear, or be produced on all instead of one only of the petals. 



One part may be occasionally added to, or subtracted from, the usual number of 

 parts in each floral whorl, more especially in regular polypetaloua flowers. 



Plants usually monoecious or dioecious may become occasionally hermaphrodite, or 

 hermaphrodite plants may produce occasionally unisexual flowers by the abortion of 

 the stamens or of the pistils. 



Leaves cut or divided where they are usually entire, variegated or spotted where 

 they are usually of one colour, or the reverse, must also be classed amongst those ac- 

 cidental aberrations which the botanist must always be on his guard against mistaking 

 for specific distinctions. 



