The pathway to botany by Leopold Hartley Grindon

Author:Leopold Hartley Grindon
Language: eng
Format: epub, pdf
Published: 1872-03-25T05:00:00+00:00

perianth, the whole of which is removable without touching the ovary; the stamens standing upon the receptacle, and thus equally free and independent. The ovaries may be numerous. The petals may be either free, or combined, or wholly wanting.

2. Perigynous Exogens. Ovary as in the first

class, but the stamens adherent to the perianth. The ovaries may here again be numerous. In other cases, petals may be wanting.

3. Epigynous Exogens. Ovary ^^ inferior,^^ owing

to the adhesion to it of the calyx-tube, or to its being sunk in an urn-like receptacle, and of course, always solitary. The presence or absence of corolla immaterial. It is true that by this latter scheme we are at times constrained to be inconsistent. By reason, for example, of the different position of the ovary, the whortleberries are dissociated from the heaths, and the cucurbits from the passion-flowers, though in other respects there is intimate relationship; while the Epacris, which has epipetalous stamens, is nevertheless located among the hypogynous families; and worse still, there are among the saxifrages, both perigynous species and epigynous ones! The exceptions, however, are far less numerous than in the

scheme first described; and a larger proportion of related families are brought into proximity.

Anomalies such as we have indicated^ are a part of the very nature of things, and render it utterly impossible to construct classes, and to frame definitions, that shall be mathematically exact, and contain nothing but what they profess to. When we quit our chairs and go to Diature, we find our ingenious fences broken down—our carefully drawn lines of demarcation vague and unreal. The utmost we can hope to accomplish in classification is to associate things round certain typical and central ideas, suflB.ciently well for practical purpose; and we may deem ourselves fortunate in the degree that the exceptions to those central ideas are fewer and less embarrassing.

ENDOGENS.

Endogens comprise all plants of the grass kind, together with sedges, rushes, and the choice tribes represented in the hyacinth, the orchis, and the lily. (Fig. 103.) In hot countries, their circle is widened by the glorious palm-trees, which, with a few exceptions, also tropical, are the only arborescent members of the class. Except in green-houses, we never see endogenous trees in England; and even the captives in our conservatories, with all their green and beautiful aspiration, give but a faint idea of the dignity of Endogens as they are in the Indies. En-

dogens are resolvable into three principal sections. Those of the first section have complete and usually brilliant flowers, and are called "Petaloid^^; those of the second section have their flowers disposed upon a *^ spadix/^ with a " spathe '^ around it, and are called " Spadiceous''; those of the third are incomplete and chaflF-like, and have the bracts which constitute their flowers disposed alternately, and are termed ^^ Glumaceous/^ Endogens also include some plants of extremely low organisation, not practically referable to any of the three general sections, such as the Lemna or duck-weed j and also some plants with extremely incomplete flowers, such as the club-rush or Typha.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.