520 PHANEROGAMS. 



primary axis, since the former often grows as vigorously as the latter, or even m(jre 

 so. In Section 24 of the chapter on General Morphology (p. 148 et seq.) the principles have 

 been laid down according to which the various systems of branching may be generally 

 classified ; these will serve also in every respect for inflorescences, and form the basis 

 of the characters of the larger groups in the following classification. Of the great 

 number of separate forms of inflorescence only the more common ones, a nomen- 

 clature for which is already provided in systematic botany, \\\\\ be enumerated^ 



A. Racemose (monopodial), Centripetal, or Indefinite Inflorescences, in the 

 widest sense of the terms, result from the primary axis or rachis of the branching system 

 producing a larger or smaller number of lateral shoots in acropetal succession ; the 

 capacity for development of each lateral shoot being smaller, or at least not greater, 

 than that of the portion of the primary axis which lies above it. 



a. Spicate Inflorescences arise when the lateral axes of the first order do not branch 



and are all floral axes ; the rachis terminates with or without a flower, 

 (a) Spicate Inflorescences with elongated rachis : — 



1. The Spike: Flowers sessile; rachis slender (as in some Grasses). 



2. The Spadix : Flowers sessile; rachis thick and fleshy, usually enveloped 



in a large spathe; bracts generally undeveloped (Aroideae). 



3. The Raceme : Flowers distinctly stalked {e.g. Cruciferae, without bracts; 



Berberis, Menyanthes, Campanula, rachis terminating in a flower), 

 (/y) Spicate inflorescences with abbreviated rachis : — 



4. The Capitulum: Rachis conical or tubular, or even hollowed out like a 



cup ; flowers sessile ; bracts frequently absent (Compositae, Dipsa- 

 caceae). 



5. The Simple Umbel: Flowers stalked and springing from a very short 



rachis {e.g. the ivy). 



b. Panicled Inflorescences arise when the lateral axes of the first order again branch 



and produce axes of the second and higher orders ; every axis or only those 

 of the last order may terminate in a flower ; the capacity for development 

 usually decreases from below upw'ards both on the lateral and on the pri- 

 mary axis. 



(a) Panicled Inflorescences with elongated axes : — 



6. The true Panicle: Axes and pedicels elongated (Crambe, grape-vine). 



7. The Compound Panicle made up of Spikes : The elongated lateral axes 



bear sessile flowers ( Veratrum, Spircea Aruncus, the ' ears ' of wheat, 

 rye, &c.). 

 (/3) Panicled Inflorescences with abbreviated axes: — 



8. Compact spike-like Panicle: The very short lateral axes are arranged 



on an elongated primary rachis (the ' ears ' of barley, Alopecurus, 

 &c.). 



9. The Compound Umbel: The very short rachis bears a densely compact 



umbel of secondary (partial) umbels usually with long stalks {cf. 

 No. 5) ; if the compound umbel is surrounded by a whorl of leaves 

 this is called the In-volucre ; a similar whorl surrounding the secondary 

 umbel is an In'volucel (secondary involucre) ; one pr both may be 

 absent ; (most Umbefliferae). 



B. Cymose, Centrifugal, or Definite Inflorescences result from the primary 

 axis branching beneath the first flower in such a manner that each lateral axis itself 



* Compare the dissimilar descriptions in Ascherson's Flora of the Province Brandenburg, 

 Berlin 1864, and in Ilofmeister's Allgemeine Morphologic, § 7. 



