ANGIOSPERMS. 



409 



the whole system appears to be composed of bifurcations, especially when 

 the older flowers have fallen off, as in many Sileneae, some Euphorbias, 

 the Labiatae, etc. The dichasium easily passes into the sympodial development 

 in the first or succeeding generations of lateral axes (Fig. 336). 

 b. Cymose itiflorescentes with a false axis [sympodial ififioresccnces). Only one 

 similar axis is developed on each axis terminating in a flower, and this is 

 repeated during several generations of axes. The basal portions of the 

 successive generations of axes may lie more or less in a straight line and may 

 become thicker than the flower-stalk (above the branching) ; in this way a 

 pseudaxis or sympodiujn is formed, which curves first to one side then to the 

 other or is straight, and the flowers appear to arise on it as lateral axes ; 

 if the sympodium is clearly developed, it simulates a spike or raceme, but may 

 be readily distinguished from it where there are bracts, because these are 

 apparently opposite to the flowers ; but they are often liable to displacement, 

 as in Sedum. 



13. Uiiiparoiis helicoid cyine or bostryx. This is a sympodial inflorescence, in 

 which the median line of each successive axis which builds up the system inclines 

 away from that of the preceding one towards the same side, i.e. each new floral 

 axis stands always right or always left of the median plane of the preceding 

 axis (Fig. -^y] C, D) ; as, for example, in the primary rays of the inflorescence 

 of Hemerocallis fitlva .and H. Jlava, and in the partial inflorescences of 

 Hypericum perforatum which are themselves arranged in a panicle 

 (Hofmeister). 



14. Uniparous scorpioid cyme or cicinnus. This is produced when the consecutive 

 branches of the system arise alternately right and left of the median line of 

 the preceding one, as in Drosera, Scilla bifolia, Tradescantia (Hofmeister). 

 Of this kind also is the inflorescence of Echeveria, where the fully developed 

 cicinnus has a false axis on which the flowers are opposite to the leaves. 

 "While the summit of the. relatively primary axis is converted into a flower, 

 a lateral axis is formed in the axil of its subfloral leaf; this developes and 

 forms a new leaf at right angles to the former one and ends in a flower, while 

 a lateral axis appears in the axil of its leaf and continues the development ; 

 the leaf formed on this last axis is in the same position as the first (Kraus). 



It follows from what has been already said, that not only different forms of one of 

 these divisions, but also forms from the two divisions {A and B) may make their 

 appearance in an inflorescence composed of several generations of shoots, and produce 

 mixed inflorescences ; a panicle in its last ramifications may form a dichasium, as in 

 many Sileneae, a dichasial inflorescence may bear capitula [Silp/iiuiu), the dichasium 

 may in its first lateral branches or in those of a higher order pass into a bostrj'x or 

 cicinnus, as in the Caryophylleae, Malvaceae, Solanaceae, Lineae, Cytiafichuin, Gagea, 

 Hemerocallis, etc. In general the form of the branching in the inflorescence is different 

 from that of the vegetative stem ; not unfrequently it passes suddenly from one to the 

 other, but the two may be connected by intermediate forms of branching. 



The older terminology has several other names of inflorescences, as cluster, corymb, 

 etc., but they only indicate the habit or external shape of the system, and must be 

 referred in a scientific description to one of the forms enumerated above or to some 

 combination of them. 



Even the inflorescences of the Boragineae which were formerly described as cicinnal 

 are, at least in all the forms in which the history of development has been investi- 

 gated, dorsiventral racemes. Two rows of flowers spring from the dorsal surface of 

 the flowering axis which is rolled up in a circinate manner at its extremity, and a row of 

 leaves is developed on each of the lateral faces and so placed that there is a leaf beneath 

 each flower, an arrangement that is found in other dorsiventral inflorescences also, such 

 as Klugia notottiana, Apofwgeton distachyon, Urtica canadensis. The Urticaceae 



