176 
PASSAGES FROM POPULAR LECTURES. 
In carrots and parsnips it is the large accumulation of 
sugar in the tap-root (about one-twelfth part) which makes 
them valuable. It has been doubted whether the hemlock 
(Conimn maculatum) is really so deadly as it was once supposed 
to be. The qualities of plants often vary with situation and 
climate. It is said that in Northern Eussia the hemlock is 
mild, and may be eaten. There is no doubt that it is poisonous 
in this country, and in more southern climates it may possibly 
be still more virulent. Celery in its wild state is poisonous also ; 
even when cultivated it is still acrid, though less dangerous 
than when growing wild, but by blanching the juicy leaf¬ 
stalks it is found that the acrid secretion is not formed. 
Those Umbelliferae which naturally inhabit central Europe 
and Britain, are mostly so much alike that, though it is easy 
to know that a plant belongs to this order, it is difficult to 
distinguish one species from another ; and this is found to be 
generally the case in any order which has very sharply defined 
characters, such as the Labiates, the Sedges, and the Grasses. 
It is easy enough to see that a certain plant is a grass, but 
what grass ? That is often a puzzling question to a young 
botanist. The species are quite distinct, but the distinctions 
are subtle and minute. The condition of such an order seems 
to be something like that of a walled city, in which the 
number of houses can only increase by crowding close together 
so that you can scarcely tell one from another. The less 
marked orders are like open towns, built with wide streets and 
gardens, and suburbs that stretch out towards one another and 
often actually meet. The buildings having plenty of room are 
easily distinguishable, wide spaces being sometimes left 
between them. 
But though these Umbelliferae are mostly so much alike, 
there are a few odd exceptions. The sea-liolly, the marsh 
pennywort, the astrantia, and the sanicle, are all quite 
abnormal, and in some distant countries these strange 
characters are so exaggerated as to make it difficult to 
recognise the species as Umbelliferae at all. Plants of this 
order are nearly all herbaceous, yet there are a few foreign 
forms which have a shrubby character. They are generally 
low-growing plants, seldom exceeding 4ft. or 5ft. high, yet 
there are a few species which run up to 12ft. or 15ft. The 
Siberian cow-parsnip, sometimes grown in gardens, has 
herbaceous stems 8ft. or 10ft. high, and umbels a foot in 
diameter. 
It is curious that while these plants exhibit in their leaves 
a variety of very beautiful forms, they should have so little to 
show in the way of blossom. Their flowers are all small and 
