90 



J. O. HAGSTROM, CRITICAL RESEARCHES OX THE TOTAMOGETONS. 



one. The subepidermal strands of the stem are lacking in the peduncle but a one- 

 celled pseudo-hypoderma has supplied their place to stiffen the organ. 



The middle part of the stem-leaf is arranged as in the cognates with a promi- 

 nent midrib possessing only one greater air-channel at the side of the narrower la- 

 cunse. The sclerenchymatous strands are numerous and the marginal bast-bundle is 

 usually strong. The leaf-base generally tapers more slowly than the apex, that is 



acute with more or less inconspicuous cusp. 

 The side-nerves join the midrib at a distance 

 from the very point of 1 — 2 times the leaf- 

 width. In broad leaves a pair of marginal 

 side-nerves occur, which join the main lateral 

 nerves a good bit of way below the point. 

 The nodes of this species lack the oil-cells often 

 occurring in others. 



The styles and stigmas correspond with 

 those of P. pusillus and others with an incon- 

 spicuous style and a low rounded stigma ex- 

 panding över the whole top surface of the 

 style and its börder. 



The characteristics of this species are the 

 short peduncles and the few-flowered spikes. 

 The latter usually consist of two closely placed 

 verticils with two flowers in each, forming a 

 little clew. The statement on var. califoniicus 

 Mor. that it sometimes has >as many as 12 

 roundish fruits» must not be understood as if 

 the spike were to contain 12 flowers. 1 have 

 seen the Pamsh's specimens underlying the 



Fi g . 35. /-. fonoaus kak. a, a leaf of ti.e broadest Morongian description, and they have no more 



Top of a leaf, flowers in the spi fc es t han has the species in 



general. Since each flower has four mericarps, 

 12 fruits mean three flowers, or 4 flowers, 

 if we suppose someone or other of the pistils to be 

 abortive as is often or mostly the fact. Charac- 

 teristic to the species is further the crested dorsal 

 keel of the fruit. The height of the keel or crest varies considcrably within the same 

 spike (see the fig. 35, F, where the dotted lino significs the reduoed keel), Another 

 peculiarity of the species is the propensity of prolonging the stem by long branches 

 from the base of the primary spike according to the type D, Fig. 2. I have measured 

 Buoh a spike-bearing branoh of the firat rank on a specimon and its lcngth ainountcd 

 to 40 cm. It bore no less than 17 leaves from the base up to the spike. The branches 

 of the first lunk, in their tum, will bear branches of the second cl c rank. This 

 mode of branohing closely corresponds to that of P. pusillus. P. foliosus also corre- 



rnore tanering form, {. C, Transverse section of a nar- 

 rowet 8-nerved leaf, / indicatea t h<- plaoes of sometimes 

 OCCnrring stranda ('", "', $tr, as nsual), 'f . D, Trans- 

 verse section of peduncle. In the centrum four vaacular 

 bondles, lus. <l into a ronnnon bundle with a common 

 xylem eavity [x), end, endodermis, l, lacnnar system, ','' 

 K, Piatil and F, fruit, ahowing the broadest and oarrowest 



form of the keel (the dotted line), ;. (!, Transverse seet. 

 of ligule, 3 ,'"' 'O frön' fielil, /•, ridges. 



