Biology Today — January 2018

1. Hygroscopic aerial roots are able to absorb water from
   atmosphere due to the presence of
   (a) root hair (b) haustoria
   (c) velamen (d) lenticels.


2. In which of the following plants, buds are modified into
   tendrils?
   (a) Passiflora, Agave
   (b) Cucurbita, Potamogeton
   (c) Antigonon, Passiflora
   (d) Vitis, Utricularia


3. Fleshy buds that participate in perennation of aquatic plants
   are found in

(a) Potamogeton (b) Oxalis

(c) Dioscorea (d) Cardamine.

4. Read the given statements and select the incorrect one.
   (a) Phylloclades are flattened green stems of unlimited
   growth.
   (b) Climbers are weak aerial stems that are unable to
   coil around an upright support by itself.
   (c) Bulbils are swollen due to storage of food and
   function as an organ of vegetative propagation.
   (d) Thalamus is a highly condensed shoot with distinct
   nodes and internodes.

Mixed Inorescence

• Here, two or more types of inflorescence get mixed up
  to form a mixed inflorescence. It may be: panicle of
  spikelets, (e.g., Oryza sativa), corymb of capitula,
  (e.g., Ageratum conyzoides), mixed spadix, (e.g.,
  banana), thyrsus (e.g., grapevine), etc.

Special Inorescence

Hypanthodium

The receptacle (peduncle) is fleshy and forms hollow structure with an apical opening (orifice) guarded by hairy

structures. Three types of flower develop on the inner surface of the receptacle.

The female flowers are towards the base, male flowers are towards the orifice and the short styled sterile female

flowers (gall flowers) are present in between, e.g., Ficus religiosa (peepal), Ficus benghalensis (banyan),

Ficus carica (fig).

Fig.: Hypanthodium of fig

Verticillaster

A modified condensed

dichasial cyme like

inflorescence in which

two whorls of 3 to 9

flowers are borne in

dichasial cyme like

manner on either side

of a node, e.g., Ocimum

sanctum.

Fig.: Verticillaster inflorescence

of Ocimum

Cyathium

The inflorescence looks like a flower. The

bracts or the involucre become fused to form

a cup shaped structure. The inflorescence

contains pedicellate, achlamydeous,

unisexual flowers of both the types, male

and female. The cup encloses a single female

flower surrounded by a large number of

male flowers. E.g., Euphorbia pulcherrima. Fig.: Cyathium inflorescence of Euphorbia

Intercalary inflorescence - Callistemon (Bottle brush)

Longest inflorescence - Amorphophalus