THE FLOWER. 



HILUM, takes also this latter name in the ovule. In the simplest 

 form of ovule (as in Fig. 5*2, 5*0). hiluin and ohala/a are one. 

 So also in cases where the body <>!' the ovule- incnn e>. as in Fig. 

 583. But verv commonly tlic place of attaclinifiit. which becomes 

 the hiluin, is more or le.ss distant from the clialaxa ; as in Fig. ~>*\ 

 and .")*?, where the hiluin i,- lateral, but the diala/a at the larger 

 end. the two being connected l>y a short ridge : and in Fig. 588 

 the two are separated by the whole length of the ovule. 



519. The simplest and most rudimentary ovule is that with- 

 out a coat, as in Mistletoe and the whole order Loranthaeea 1 , and 

 in Santalaceae and (inetaceae. This has been called a naked 

 ovule; but long before ovules of such simplicity were known 

 this term had been appropriated to those of Gymnosperms, in 

 the sense of destitute of ovarial or pericarpial covering, i. e. to 

 uncovered ovule, not to uncovered nucleus. The ovule consist- 

 ing only of nucleus may be termed (after Alph. DeCandolle) 

 simple, or better achlamydeous. 1 



520. The tunicated or chlamydeous ovule is of three principal 

 kinds, with one or two subordinate modifications. These are 

 the orthotropous, campylotropous, and anatropous, and the modi- 

 fication called half-anatropous, or amphitropous. 2 



521. Orthotropous (Fig. 580, 582, 585), or straight ovule, is 

 the simplest but least common species, being that in which the 



585 



chalaxa is at the evident base, and the oriiice at the opposite 

 extremity, the whole ovule straight (as the first part of the name 

 denotes) and svmmetrical. Afropous, meaning not turned at 

 all, is a later and et3'mologically much better name, but it has 



1 An epidermal stratum or tegument may not be wanting to such ovules, 

 forming a sort of adherent rove-ring; but this in nature and origin is not 

 similar to the uvular coats. 



2 In Latin form. tii-tlmim/Hi. campylotropa, tnitit/-<>/><i, amphitropa, names given 

 liy Mirlid, and referring to the way in which the ovule is tunml either on 

 itself or on its support. Some English botanists incongruously write ortho- 



&C. 



FIG. 585. Orlii)tr<>iii>n.s nr AtrOpOOS OTUlO Of Baofewbeat. r.si;. 

 ovule of rliiokiv, ,l. r,S7. Vnipliitropnua OTUle of Hallow, fiss. Anntrnpnus ovule of a 

 Violet. Tlie letter /( indicates the liilum; r, the clmlaza. \vhich in 585 and 580 corre- 

 sponds to the liilum; /, the foramen or orifice; r, the rbaplie. 



