MR. J. MIERS ON THE FAMILY OF TRIURIACEjE. 51 



rescence, unisexual flowers, simple perianthium, similar in both sexes, nearly cleft to its 

 base into regular segments, with a valvate aestivation and a cellular epidermis ; the male 

 flowers furnished with few stamens, which are seated opposite the segments upon a fleshy 

 disc, or more or less prominent androphorum ; very numerous distinct carpels in the female 

 flowers, having a more or less lateral style, and a single erect ovule, and offering a seed of 

 most peculiar structure. These characters do not conform with any other natural family ; 

 for which reason, when Trinris only was known, I suggested it should form the type of a 

 new order. In regard to the affinities of this group of plants, it is manifest that they 

 bear no analogy with Menispermece or Smilacece, as Mr. Gardner at first inferred ; nor can 

 they be held related to Artocarpece, where that zealous botanist, following the example 

 of Endlicher, referred Sciaphila and Hyalisma. Their structure, totally different habit, 

 simple style, erect ovule, arilliform envelope, and acotyledonous seed, distinguish them in 

 the most decided manner both from Artocarpece and Urticece. In order to arrive at their 

 real position in the natural system, we must first determine in what class to seek their 

 nearest alliance. 



The facts before shown lead to the inference, that the seed of the Triuriacece is not only 

 acotyledonous, but inembryonal, a fact not singular in the history of Phsenogamous plants. 

 But does the absence of the usual elements constituting an embryo, viz. cotyledon, radicle, 

 and plumula, imply the want of the ordinary function of the reproductive power of the 

 plant from its seed so constituted ? It appears that the presence of such elementary parts 

 is not always a necessary condition to the capacity of vegetable reproduction. According 

 to the views of modern physiologists, the embryo is but a normal condition of a leaf-bud 

 and stem, whose gradual increment is due to certain secretory deposits, regulated by fixed 

 laws of cellular expansion, thus producing a highly complicated or low degree of vascular 

 development in every pheenogamous plant, from the smallest herb to the most gigantic 

 tree of the forest. But in those plants destitute of real leaves, and composed of little more 

 than simple cellular tissue, void of green colour, and of the fibres and ducts that enter into 

 the structure of most other vegetable substances, we can hardly expect to meet with a 

 reproductive embryo organized in the form of such a normal bud ; and it is only consist- 

 ent with so simple a structure, to expect a nucleus equally simple in its nature, formed 

 merely of an aggregation of cytoblasts, which, under favourably-exciting influences, are 

 endowed with the faculty of self-development. Indeed, we have no satisfactory evidence 

 of the existence of an embryo, in the ordinary sense of this term, in the seeds of Burman- 

 niacece, &c, notwithstanding that we know they must be constantly reproduced from their 

 seeds. 



Mr. Robert Brown, in his learned memoir upon Rafflesia, in the nineteenth volume of 

 the Society's Transactions, has shown that the seeds of that genus, although albuminous, 

 possess an embryo of the most simple and reduced form ; but the Balanophorete, which 

 that most distinguished botanist holds to be quite a distinct and even distant family from 

 the Rafflesiacece, have been shown by Mr. Griffith to be truly inembryonal ; and in his 

 paper on Balanophora * he describes the structure of its nucleus, and the contents of its 

 cells, as being precisely similar, even in words that answer in every respect for all that is 



* Trans. Linn. Soc. vol. xx. pp. 98, 101 and 102. 



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