

GENEBAL HABIT-LEAVES. 



In those species that appear to be amuml * k^ «~o. • 



hmn-rP 1.11. i„.-^ J*~ „ G , annual the root ^ woody, the rootlets bein^ 



3 



all fibrous (P. bete, lyrata\ or some of tW ♦ 7 T . y ' 6 r00tlet8 bei 



z z • \ "1 h these towar( is the point beino- tuberous (P 



corymbosa, zeylanica), the main root in this latter ™ u • lUD ™>us (^ 



mm* t.K« J,;^ _. v * "\ ™ S iatter ^ 0U P being premorse 



either 



carnosu . 



perenn 



species the rhizome may be woodv with fiw. f. 1 . 8 ^ remorse - m , 



with fibrous and tuberous roZ^Zl^/T ' ( '" T^ "***' **'^ 



tuberous rootlets only (P. ^ Sfclt^ **" 



fleshy-cactoid-and may either be with™.* ~Jn ! / ».?, me M thlck aild 



pycnantha). The rhizome may be erect or horizontal, and ,u — :. \' T™ [ h 



erect is often branched 



it 

 le 



downwards (P. Daltom, alasckanica), but rarely upwards (P. Wallickii); when 

 2 often branches in the direction of growth (P. tf„,^, ^ /^p 

 erect rhizome is usually underground or has only the crown projecting .bote e 

 surface; ^ honzonta is generally slender and creeps along the surfacef only L 

 being cactoid P. Clark*, Prazmana, irichoglossa), and then deeply buried. Thick fleshv 

 rhizomes usually, woody rootstocks rarely, have a crown of membranous scales K 

 when the rhizome is erect are crowded and sheath the base of the stem ; when it i! 

 horizontal hey are separated by internodes. They vary from large ovate </>. pycn(llliha 



doluhorrhza), or long lanceolate (P. schizorrhyncha, lachnoglossa), to exceedingly minute 

 (P. irichoglossa). Flagella occasionally arise from their axils (P. Kingii), and in the 

 species with cactoid underground rootstocks the flagella pass directly to the surface of 

 the soil, giving off immediately below it collars of fibrous rootlets and being continued 

 above into relatively thick stems. And unless specimens are available in which 

 the connection of these flagella with their rootstock remains intact, these specus 

 ~\ trichoglossa, Clarkei, Prainiana) may readily be mistaken for plants of annual habit 

 A small but distinct group of nearly allied forms (P. Regeliana, Artsclaeri, acaulis) 



is stemless; elsewhere in the genus there is a distinct stem— sometimes very short 

 (P. bella, lyrata, nepalensis, P r zeiv alskii) , but ordinarily more or less elongated, and in two 

 Indian species (P. excelsa, dolicliorrhiza), at times exceeding a metre in height— hollow 

 and round, usually smooth, though occasionally grooved (P. Clarkei), or 2— 4-gonous th 

 angles rarely being almost winged (P. rex). The thickness varies from that of a crow- 

 quill (P. tenuicaulis) to that of the little finger (P. excelsa). The stem is usually simple • 

 when branched the branches, like the leaves, may be alternate (P. carnosa), opposit* 

 (P. flexuosa), or whorled (P. pectinata). The branches may be fastigiate (P. Collet Hi) or 

 spreading (P. tenuirostris), and simple or, rarely, branched a second time (P. gracilis). 

 Branching at the base (P alaschanica, confertiflora, cheilanthifolia, Boy lei) is not unusual, 



but; branching higher up is exceptional as regards Indian species, though occasionally 

 such branching may occur owing to injury to the upper part of the stem in species not 

 normally characterised by a branching habit. 



The stem and branches may be glabrous, but are more often variously hirsute or 

 pilose; not infrequently where the leaves are verticillate the stem is 2 — 5-fariously hairy 

 the lines of hairs being determined by the number of leaves in a whorl. 



At the base of the stem there is a circle of radical leaves ; these usually disappear 

 when the root or rootstock is woody and the rootlets are fibrous, but persist where the 

 rootlets are tuberous or the rhizome is cactoid. And in those species where the root 

 are sometimes fibrous, sometimes tuberous, the radical leaves correspondingly sometimes 

 are evanescent and sometimes persist. At the same time a few annual species have a 

 rosette of radical leaves (P. bella), while some species with thickened rhizomes may lose 



<• 



y 



Ann. Roy. Bot. Gard. Calcutta, Vol. Ill 



