Page:Popular Science Monthly Volume 27.djvu/508

 the ease in genera where the various species differ greatly in habit? I have already incidentally given cases which show that this is not so, but let us take some group—for instance, the genus Senecio, to which the common groundsel (Fig. 24) belongs, as a type well known to all of us and look at it a little more closely.

The leaves of the common groundsel I need not describe, because they are familiar to us all. This type occurs in various other species of more or less similar habit.

On the other hand, the fen Senecio(S. paludosus) and the marsh Senecio (S. palustris), which live in marshy and wet places, have long, narrow, sword-shaped leaves, like those of so many other plants which are found in such localities. The field Senecio (S. campestris, Fig. 34), which lives in meadows and pastures, has a small terminal head of flowers springing from a rosette of leaves much like those of a common daisy (Bellis perennis); a Madagascar species, as yet I believe unnamed, is even more like a daisy. Senecio junceus looks much like a rush; S. hypochcerideus, of South Africa, strikingly resembles a hypochœris, as its name denotes. A considerable number of species attain to a larger size and become woody so as to form regular bushes. S. buxifolius has very much the general look of a box, S. vagans of a privet, S. laurifolius of a laurel, ericœfolius of a heath, pinifolius of a fir, or rather a yew.

Again, some species are climbers: S. scandens and S. macroglossus have leaves like a bryony; S. araneosus and S. tamoides like a smilax or (yam) tamus; S. tropœolifolius like a tropæolum.

Among the species inhabiting hot, dry regions are some with swollen, fleshy leaves, such as S. haworthii, from the Cape of Good Hope, and S. pteroneura, from Magador. Senecio rosmarinifolius, of the Cape, is curiously like a rosemary or lavender.

Lastly, some species may almost be called small trees, such as S. populifolius, with leaves like a poplar; and S. amygdaloides, like an almond.

I might mention, if space permitted, many other species which, as their names denote, closely resemble forms belonging to other groups—such, for instance, as Senecio lobelioides, erysimoides, bupleurioides, verbascifolius, juniperinus, ilicifolius, acanthifolius, linifolius, platanifolius, graminifolius, verbenefolius, rosmarinifolius, coronopifolius, chenopodifolius, lavanderiæfolius, salicifolius, mesembryanthemoides, digitalifolius, abietinus, arbutifolius, malvæfolius, erodiifolius, halimifolius, hakeæfolius, resedæfolius, hederæfolius, acerifolius, plantigineus, castaniæfolius, spiræifolius, bryoniæfolius, primulifolius, and many