430 MORPHOLOGY. 



above, that even before the rudiment of the embryo exists, after 

 the complete formation of the seed-bud a new structure proceeds 

 from the funiculus, very similar to the coats of the seed-bud. But 

 the production of such a structure is much more frequent after the 

 formation of the embryo has begun. It is very various, according 

 as it advances farther or is early arrested in its development (as in 

 most LeguminoscB) ; according as the structure envelopes the whole 

 seed as a continuous coat (in Nymphaa, Passiflora, Taxus), or 

 presents itself in separate lobes and strips, here and there connected 

 together (in Myristica (?) ) ; or, lastly, consists merely of long hairs, 

 which envelop the seed (in Salix) : very various, according as this 

 organ is merely membranous, or dry and fibrous (Nymph&a. Salix) ; 

 fleshy and juicy ( Taxus) ; or, lastly, becomes broken up into iso- 

 lated juicy cells, which surround the seed (Arum., Mamillaria). In 

 this last transformation the conducting tissue and a portion of the 

 inner surface of the cavity of the germen usually take part. The 

 former structures, which all have the same origin, namely, are 

 additional developments of the funiculus, have been partly deno- 

 minated by the name aril (arillus) ; the latter, where the isolated 

 juicy cells no longer betray their origin, as pulp (pulpa). Par- 

 ticular forms, e. g. in Salix, are described as a coma. 



The heterogeneous things which are usually collected under the name 

 arillus pass belief, except with those who know that Botany has 

 hitherto established its definitions almost solely on superficial impressions 

 and external resemblances, or at best on comparisons which, from the 

 want of sure foundations, are valueless. In Zoology the comparative 

 method had still an import, since one organism understood as completely 

 as possible, according to its course of development, the human, could be 

 taken as a basis ; yet the tracing of development has even asserted its 

 right here, and the most recent researches have proved to what mistaken 

 directions and complications mere comparisons may lead in the absence 

 of developmental history. In Botany, on the other hand, when we do 

 not yet understand the structure and development of a single plant com- 

 pletely, such a comparative method is an empty exercise of the wit. 

 There can be no doubt that every contest is childish in which no critical 

 tribunal, no principle for the decision, exists ; that a scientific investi- 

 gation is wholly vain if a principle of truth have not been previously 

 discovered. Botany possesses nothing of the kind. Link (Elem. Phil. 

 Bot. ed. 2. vol. ii. p. 265.) says : " At the place where the funiculus 

 enters the seed a variously-shaped part often occurs, which has origin- 

 ated from the thickened and expanded funiculus, but is invested with 

 an epidermal layer, of which the funiculus is destitute : this is called 

 an aril. It is globular (Euphorbia), a cup with an entire margin (Ana- 

 gallis\ a four-toothed cup (Polygala), a lacerated cup (Myristica)" 

 Mirbel had already shown that the gland in Euphorbia is totally different 

 from an aril, and does not arise from the funiculus at all ; in Anagallis 

 there exists nothing bearing the most distant resemblance to an aril ; in 

 Polygala there is only a rather loose epidermis to the seed : and all these 

 are thrown together by Link. Any one who calls the elastic epidermis 

 of the seed of Oxalis an arillus is just as much and just as little jus- 

 tified as he who chooses to call it epidermis, or even pulp. The strife is 



