HYDRANGEA. UMBELLIFEROUS TRIBE. 449 



warm weather. When the floral envelopes are over-developed 

 by cultivation, the flowers become barren, and the plant must 

 be propagated by cuttings. They grow in closely-set clusters ; 

 and a little examination of one of these will often disclose many 

 curious irregularities, produced by the partial union of two or 

 more flowers, arising from the want of room for their full deve- 

 lopment. The regular number of the large coloured leaflets is 

 four ; but not unfrequently we find a flower possessing five, six, 

 seven, eight, or even more ; and the additional ones are easily 

 shown to be derived from other flowers, which are partially 

 fused or melted down, as it were, into the first. The Hydrangeas 

 are likewise remarkable for the varieties of colour to which the 

 same species, or even the same individual, is subject, according 

 to the soil in which it grows. Their natural and most common 

 colour is red ; in a poor soil, however, they become of a dingy 

 green ; but when grown in richer mould, especially in peat- 

 earth, and watered with an alkaline solution, or manured with 

 wood-ashes, they assume a rich blue tint, and their clusters 

 increase in size and present a very handsome appearance. 



617. We next come to an order of great extent and import- 

 ance ; and one that is marked by an evident peculiarity, which 

 enables us to distinguish very readily, in almost every instance, 

 the plants that belong to it. This is the order UMBELLIFERJE, 

 the Umbelliferous tribe, so named from the peculiar arrangement 

 of the flowers upon the stem, which pervades the whole group. 

 If we look at a plant of any common species, such as the 

 Parsley or Hemlock, we observe that the flower-stem divides at 

 the top into a number of short slender rays, which all proceed 

 from one point, just as do the stretchers of the umbrella. If the 

 flowers were borne on these, the whole set would be considered 

 as forming a simple umbel, such as we find in the Geranium and 

 many other plants. But in the Umbellifera?, we commonly find 

 that each stalk of the umbel subdivides again, bearing a second 

 set of rays that carry the flowers at their extremities, which 

 itself constitutes an umbel. The whole system is then termed 

 a compound umbel; and it is this which is characteristic of 

 the order. It may be further noticed, that the stems are 



